WO2017151901A1

WO2017151901A1 - Medical surfaces indicating sterilization or disinfection, and methods of making and using the same

Info

Publication number: WO2017151901A1
Application number: PCT/US2017/020422
Authority: WO
Inventors: Todd J. HARRIS; Edward T. CASTELLANA
Original assignee: Instructive Color, Llc
Priority date: 2016-03-04
Filing date: 2017-03-02
Publication date: 2017-09-08

Abstract

Embodiments of the present invention provide medical surfaces indicating sterilization or disinfection, and methods of making and using the same. Under one aspect, a method for sterilizing or disinfecting a medical surface includes providing a medical surface comprising a photonic crystal. The method also can include, responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, Bragg diffracting light of a first wavelength by the photonic crystal. The method also can include applying the sterilizing or disinfecting liquid to the photonic crystal. The method also can include, responsive to applying the sterilizing or disinfecting liquid, Bragg diffracting light of a second wavelength by the photonic crystal, the first wavelength being distinguishable from the second wavelength. The method also can include, based on the Bragg diffraction of the light of the second wavelength, determining that the medical surface is respectively sterilized or disinfected by the sterilizing or disinfecting liquid.

Description

MEDICAL SURFACES INDICATING STERILIZATION OR DISINFECTION, AND METHODS OF MAKING AND USING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.

62/303,824, filed on March 4, 2016, the entire contents of which are incorporated by reference herein.

FIELD

[0002] This application relates to sterilization or disinfection of medical surfaces.

BACKGROUND

[0003] Medical surfaces can be sterilized or disinfected in a variety of suitable ways known in the art. For example, certain medical devices are made of metal, and thus suitably can be autoclaved to sufficiently high temperatures to satisfactorily kill microbial life and spores, and thus to sterilize their surfaces, without damage. However, autoclaving can be unsuitable for sterilizing or disinfecting some medical surfaces, such as polymer-based medical surfaces that would be damaged at sufficiently high temperatures to satisfactorily kill microbial life, or such as surfaces that are relatively immovable, such as a floor, wall, counter, or door of a health care facility. Medical surfaces for which autoclaving is unsuitable, but for which sterilization or disinfection nonetheless is desired, potentially can be sterilized or disinfected using a sterilizing or disinfecting liquid or gas. For guidelines published by the Center for Disease Control (CDC) regarding protocols for disinfecting and sterilizing different medical surfaces that may be present in a medical facility, see Rutala et al., "Guideline for Disinfection and Sterilization in Health care Facilities, 2008," the entire contents of which are incorporated by reference herein.

SUMMARY

[0004] Embodiments of the present invention provide medical surfaces indicating

sterilization or disinfection, and methods of making and using the same. Under one aspect, a method for sterilizing or disinfecting a medical surface includes providing a medical surface including a photonic crystal. The method also can include, responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, Bragg diffracting light of a first wavelength by the photonic crystal. The method also can include applying the sterilizing or disinfecting liquid to the photonic crystal. The method also can include, responsive to applying the sterilizing or disinfecting liquid, Bragg diffracting light of a second wavelength by the photonic crystal, the first wavelength being distinguishable from the second wavelength. The method also can include, based on the Bragg diffraction of the light of the second wavelength, determining that the medical surface is respectively sterilized or disinfected by the sterilizing or disinfecting liquid.

[0005] Some embodiments further include removing the sterilizing or disinfecting liquid from the photonic crystal; and responsive to the removing of the sterilizing or disinfecting liquid, again Bragg diffracting light of the first wavelength by the photonic crystal. Some embodiments further include, based on the Bragg diffraction of light of the first wavelength again, determining that the medical surface is ready for use.

[0006] In some embodiments, the photonic crystal is embedded within the medical surface.

[0007] In some embodiments, the photonic crystal is adhered to the medical surface.

[0008] In some embodiments, the photonic crystal is self-assembled onto the medical surface.

[0009] In some embodiments, the photonic crystal is painted onto the medical surface.

[0010] In some embodiments, the photonic crystal is welded to the medical surface.

[0011] In some embodiments, the medical surface includes a first polymer, and the photonic crystal includes a second polymer. In some embodiments, the first polymer is different than the second polymer.

[0012] In some embodiments, a surface of the photonic crystal is functionalized to enhance wetting of the photonic crystal by the sterilizing or disinfecting liquid. In some embodiments, the functionalization enhances wetting of the photonic crystal by the sterilizing or disinfecting liquid selectively relative to at least one other liquid. [0013] In some embodiments, the medical surface defines at least a portion of a medical device. In some embodiments, the medical device includes an intravascular device. In some embodiments, the medical device includes a connector.

[0014] In some embodiments, the medical surface defines at least a portion of a tray. In some embodiments, the medical surface defines at least a portion of a medical drape. In some embodiments, the medical surface defines at least a portion of a floor, wall, counter, or door of a health care facility.

[0015] In some embodiments, the sterilizing or disinfecting liquid includes ethanol. [0016] In some embodiments, the photonic crystal includes an opal.

[0017] In some embodiments, the photonic crystal includes a substantially periodic array of pillars surrounded by air.

[0018] In some embodiments, the first and second wavelengths are visible to the human eye.

[0019] Under another aspect, a medical surface includes a photonic crystal disposed on or embedded within the medical surface. The photonic crystal Bragg diffracts light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid. The photonic crystal Bragg diffracts light of a second wavelength responsive to applying the sterilizing or disinfecting liquid, the first wavelength being distinguishable from the second wavelength. The medical surface is respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid.

[0020] Under another aspect, a sticker includes a photonic crystal disposed on or embedded within a surface of a polymer. The photonic crystal Bragg diffracts light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid. The photonic crystal Bragg diffracts light of a second wavelength responsive to applying the sterilizing or disinfecting liquid, the first wavelength being distinguishable from the second wavelength. The sticker is respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid. The sticker further includes an adhesive disposed on the polymer, the adhesive configured to adhere the polymer to an article. [0021] Under another aspect, a wall, floor, counter, or door includes a photonic crystal disposed on or embedded within the wall, floor, counter, or door. The photonic crystal Bragg diffracts light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid. The photonic crystal Bragg diffracts light of a second wavelength responsive to applying the sterilizing or disinfecting liquid, the first wavelength being distinguishable from the second wavelength. The wall, floor, counter, or door is respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid.

BRIEF DESCRIPTION OF DRAWINGS

[0022] FIGS. 1 A-1F illustrate cross-sections of exemplary medical surfaces indicating sterilization or disinfection, according to some embodiments of the present invention.

[0023] FIG. 2A illustrates an exemplary spectrum of wavelengths that can be Bragg diffracted by a medical surface prior to sterilization or disinfection, according to some embodiments of the present invention.

[0024] FIG. 2B illustrates an exemplary spectrum of wavelengths that can be Bragg diffracted by a medical surface responsive to application of a sterilizing or disinfecting liquid, according to some embodiments of the present invention.

[0025] FIG. 2C illustrates an exemplary spectrum of wavelengths that can be Bragg diffracted by a medical surface after evaporation of a sterilizing or disinfecting liquid, according to some embodiments of the present invention.

[0026] FIG. 3 illustrates steps in an exemplary method for sterilizing or disinfecting a medical surface, according to some embodiments of the present invention.

[0027] FIG. 4 illustrates steps in an exemplary method for making a medical surface indicating sterilization or disinfection, according to some embodiments of the present invention.

[0028] FIGS. 5A-5E are photographic images of an exemplary medical surface indicating sterilization or disinfection, according to one non-limiting embodiment of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present invention provide medical surfaces indicating sterilization or disinfection, and methods of making and using the same.

[0030] More specifically, the present medical surfaces suitably can be used to provide an optically detectable indication that a sterilizing or disinfecting liquid has been applied to that surface, and that the surface therefore is sterilized or disinfected. The present medical surfaces also suitably can be used to provide an optically detectable indication that the sterilizing or disinfecting liquid has evaporated, and that the surface therefore is ready for use, in addition to being sterilized or disinfected. For example, as described in greater detail herein, the medical surface can include a photonic crystal. Responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, the photonic crystal can Bragg diffract light of a first wavelength. Responsive to application of the sterilizing or disinfecting liquid, the photonic crystal can Bragg diffract light of a second wavelength. The first wavelength can be distinguishable from the second wavelength. Accordingly, based on the Bragg diffraction of the light of the second wavelength, it can be determined that the medical surface is sterilized or disinfected. Such color-changing indication potentially can meaningfully improve health care professional and consumer compliance with sterilization and disinfection protocols, and thus potentially can improve outcomes of patients.

[0031] First, some terms used herein will be briefly explained. Then, some exemplary medical surfaces, and some exemplary methods of making and using medical surfaces, will be described.

Exemplary Terms

[0032] As used herein, the term "heath care facility" is intended to mean an environment in which animals, such as humans, are treated by a health care professional. Health care facilities can include, but are not limited to, hospitals, emergency rooms, and clinics, and potentially also can include homes or places of business in which animals, such as humans, are treated by a health care professional. [0033] As used herein, the term "medical surface" is intended to mean an outer portion of an article that can be used in a health care facility, and that potentially can directly or indirectly transmit microbial life from that medical surface to an animal, such as a human. Examples of articles that can include medical surfaces include, but are not limited to, medical devices, trays, medical drapes, and floors, walls, counters, and doors of a health care facility.

[0034] As used herein, the term "medical device" is intended to mean an article that is brought into direct contact with the skin, flesh, or bodily fluid of an animal, such as a human, or that is brought into direct contact with a fluid that is brought into direct contact with the skin, flesh, or bodily fluid of an animal, and that potentially can directly transmit microbial life to that animal.

[0035] As used herein, the terms "sterilized," "sterilization", and the like are intended to mean that all forms of microbial life on a surface have been destroyed. As used herein, the terms "disinfected," "disinfection," and the like are intended to mean that many or all pathogenic microorganisms, except bacterial spores, on a surface have been destroyed. Note that a surface that is sterilized necessarily is disinfected, whereas a surface that is disinfected is not sterilized, because disinfection is, by definition, not sporicidal. However, note that some health

professionals and the technical and commercial literature sometimes use the terms "disinfection" and "sterilization" interchangeably or can refer to articles as being "partially sterile."

[0036] As used herein, the suffixes "cide" and "cidal" are intended to denote killing action. For example, a germicide is an agent that can kill microorganisms, particularly pathogenic organisms ("germs"). The term "germicide" includes both antiseptics, which are applied to living tissue and skin, and disinfectants, which are applied only to inanimate objects. Virucides, fungicides, bactericides, sporicides, and tuberculocides can kill the type of microorganism identified by the prefix. For example, a bactericide is an agent that kills bacteria.

[0037] As used herein, the term "sterilizing liquid" is intended to mean a condensed-phase fluid that sterilizes a surface to which the condensed-phase fluid is applied. The term "sterilizing liquid" is intended to exclude a relatively thin layer of fluid that can condense upon a surface from a gaseous phase. [0038] As used herein, the term "disinfecting liquid" is intended to mean a condensed-phase fluid that disinfects a surface to which the condensed-phase fluid is applied. The term

"disinfecting liquid" is intended to exclude a relatively thin layer of fluid that can condense upon a surface from a gaseous phase.

[0039] Note that there can be different degrees of disinfection. For example, a "high level disinfectant" refers to killing all microorganisms except for bacterial spores, whereas a "low- level disinfectant" refers to killing most vegetative bacteria, some fungi, and some viruses in a practical period of time, e.g., in less than 10 minutes. An "intermediate-level disinfectant" can be cidal for mycobacteria, vegetative bacteria, most viruses, and most fungi, but does not necessarily kill bacterial spores. Different germicides can differ markedly from one another, primarily in their antimicrobial spectrum and rapidity of action. In some circumstances, a liquid can be a disinfecting liquid of desired degree based on being applied for a sufficient amount of time to disinfect a surface to that desired degree, and can be a sterilizing liquid based on being applied for a sufficient amount of time to sterilize a surface. As one nonlimiting example, a liquid such as 2% glutaraldehyde can be a low-level disinfectant based upon being applied for ten minutes or less, can be a high-level disinfectant based upon being applied for twenty minutes, or can be a sterilant based upon being applied for 3-12 hours.

[0040] Alcohol is one example of a sterilizing or disinfecting liquid. As used herein, and as is consistent with the term's use in the healthcare setting, "alcohol" typically refers to two water- soluble chemical compounds, ethyl alcohol (ethanol) and isopropyl alcohol, that have germicidal characteristics. These alcohols are rapidly bactericidal, rather than bacteriostatic, against vegetative forms of bacteria; they also are tuberculocidal, fungicidal, and virucidal, but may not necessarily destroy bacterial spores. The cidal activity of these alcohols can drop sharply when diluted below 50% concentration. Exemplary bactericidal concentrations of these alcohols is 60%-90% solutions in water (volume/volume).

[0041] As used herein, the term "ready for use" is intended to mean that a sterilizing or disinfecting liquid has been applied to a medical surface and subsequently has been removed, e.g., has evaporated, so as to inhibit direct or indirect contact between the sterilizing or disinfecting liquid and an animal, such as a human. [0042] As used herein, the term "photonic crystal" is intended to mean a lattice that is periodic in two dimensions or in three dimensions so as to cause Bragg diffraction, e.g., constructive scattering, of light of one or more wavelengths. Note that a photonic crystal can be, but need not necessarily be, defined within a crystalline material. For example, a photonic crystal can be defined within an amorphous material, polycrystalline material, polymer, or the like.

Exemplary Medical Surfaces

[0043] In some embodiments, a medical surface is modified so as to include a photonic crystal that provides a detectable indication of whether a sterilizing or disinfecting fluid has been applied to the medical surface, and thus whether the medical surface has been sterilized or disinfected. More specifically, the photonic crystal can include a periodic two-dimensional or three-dimensional array of solid state material that is characterized by a first refractive index, and that defines sidewalls separated from one another by gaps. When exposed to air in the absence of a sterilizing or disinfecting liquid, the gaps can be filled with air, which has a second refractive index. Based on the periodicity of the solid state material and the first and second refractive indices, the photonic crystal can Bragg diffract light of a first wavelength. Based on application of a sterilizing or disinfecting liquid to the photonic crystal, that liquid - which has a third refractive index that is significantly higher than the second refractive index - can flow into the gaps. Based on the periodicity of the solid state material and the first and third refractive indices, the photonic crystal can Bragg diffract light of a second wavelength that is

distinguishable from the first wavelength. In one embodiment, based on the Bragg diffraction of the light of the second wavelength, it can be determined that the medical surface is sterilized or disinfected, e.g., because the photonic crystal of the medical surface is sufficiently contacted with the sterilizing or disinfecting liquid as to fill the gaps. In another embodiment, removal of the liquid (e.g., via evaporation) allows air to once again fill the gaps in the photonic crystal, thereby switching the Bragg diffraction of the light back to the first wavelength, it can be determined that the medical surface is sterilized or disinfected and ready for use, e.g., because the photonic crystal of the medical surface was sufficiently contacted with the sterilizing or disinfecting liquid for a sufficient amount of time and such liquid also has been removed. [0044] It should be appreciated that a medical surface can be modified in any suitable number of ways so as to include a photonic crystal. For example, FIGS. 1 A-1F illustrate cross- sections of exemplary medical surfaces indicating sterilization or disinfection, according to some embodiments of the present invention. Other embodiments suitably can be used.

[0045] In the exemplary embodiment illustrated in FIG. 1 A, article 100 includes medical surface 110 upon which photonic crystal 120 is disposed. Photonic crystal 120 can Bragg diffract light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, and can Bragg diffract light of a second wavelength responsive to applying the sterilizing or disinfecting liquid. The first wavelength can be distinguishable from the second wavelength. The medical surface can be sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid.

[0046] Article 100 can include any suitable article that can be used in a health care facility, including, but not limited to, a medical device, a tray, a medical drape, or a floor, wall, counter, or door of a health care facility. Additionally, article 100 can include any suitable material or combination of materials, which can be, but need not necessarily be, the same as a material or combination of materials from which photonic crystal 120 is formed. For example, article 100 can include one or more materials selected from a metal, polymer, plastic, glass, semiconductor, dry wall, wood, ceramic, tile, fabric, or composite. As such, medical surface 110 of article 100, which can define at least a portion of an outer surface of article 100, can include one or more of such materials.

[0047] Photonic crystal 120 can include any suitable combination and arrangement of materials so as to define a periodic structure that can Bragg diffract light of a first wavelength. For example, in the embodiment illustrated in FIG. 1 A, photonic crystal 120 includes a periodic, two-dimensional, laterally arranged array of solid state material 121 that is characterized by a first refractive index, and that defines sidewalls 122 separated from one another by gaps 123. When exposed to air in the absence of a sterilizing or disinfecting liquid, gaps 123 can be filled with air, which has a second refractive index. Based on the periodicity of solid state material 121 and the first and second refractive indices, photonic crystal 120 can Bragg diffract light of a first wavelength. For example, FIG. 2A illustrates an exemplary spectrum of wavelengths that can be Bragg diffracted by a medical surface prior to sterilization or disinfection, according to some embodiments of the present invention. Spectrum 210 of diffracted wavelengths can be centered at a first wavelength λι, can have any suitable spectral shape, such as Gaussian or Lorentzian, and can have a bandwidth that can be characterized using any suitable metric, such as full-width-at-half-maximum (FWHM). In one nonlimiting, illustrative embodiment, first wavelength λ] is visible to the naked human eye. Alternatively, first wavelength λ j can be invisible to the naked human eye but can be detected using a suitable detector, such as a photomultiplier, photodiode, CCD, or photovoltaic.

[0048] Additionally, or alternatively, photonic crystal 120 can include a periodic, three- dimensional, laterally and vertically arranged array of solid state material 121 that is

characterized by a first refractive index, and that defines sidewalls 122 that are not only separated from one another by gaps 123 but that also themselves include gaps 124, 124', or 124" defined therein, such as respectively illustrated in FIGS. 1D-1F. For example, in the exemplary embodiment illustrated in FIG. ID, sidewall 122 can define a periodically curved profile (e.g., a generally sinusoidal profile) that defines periodic gaps 124 arranged vertically within solid state material 121, along sidewall 122. As another example, in the exemplary embodiment illustrated in FIG. IE, sidewall 122' can define a periodically rectangular profile that defines periodic gaps 124' arranged vertically within solid state material 121 ', along sidewall 122' . As another example, in the exemplary embodiment illustrated in FIG. IF, sidewall 122 can define a periodically triangular profile that defines periodic gaps 124" arranged vertically within solid state material 121", along sidewall 122". Any suitable vertically periodically arranged shapes can be used. When exposed to air in the absence of a sterilizing or disinfecting liquid, gaps 123 and gaps 124, 124', or 124" can be filled with air, which has a second refractive index. Based on the periodicity of solid state material 121, 121 ', or 121", the periodicity of gaps 124, 124', or 124" and the first and second refractive indices, photonic crystal 120 can Bragg diffract light of a first wavelength, and optionally can Bragg diffract light of multiple wavelengths. For example, the periodicity of gaps 123 can Bragg diffract light of a first wavelength, and the periodicity of gaps 124, 124', or 124" can Bragg diffract light of a wavelength that is different from the first wavelength, e.g., a fourth wavelength. Additionally, note that vertically periodic sidewalls 122, 122', 122" illustrated in FIGS. 1D-1F optionally can be used independently of a horizontally periodic array such as illustrated in FIGS. 1A-1C. That is, in certain embodiments, the vertical periodicity of sidewalls 122, 122', 122" such as illustrated in FIGS. 1D-1F suitably can Bragg diffract light of a first wavelength when filled with air.

[0049] One skilled in the art readily would be able to co-select the dimensions and periodicity of gaps 123, 124, 124', or 124" and a composition of solid state material 121 so as to Bragg diffract light of a first wavelength in the absence of a sterilizing or disinfecting liquid. In nonlimiting examples, horizontal gaps 124 or vertical gaps 124, 124', or 124" independently can have a dimension of about 1 nm to about 500 nm, or about 1 nm to about 200 nm, or about 1 nm to about 50 nm, or about 5 nm to about 50 nm, or about 10 nm to 30 nm; and can have a periodicity of about lnm to about 50,000 nm, or about 1 nm to about 5,000 nm, or about 1 nm to about 500 nm, or about 1 nm to about 200 nm, or about 1 nm to about 50 nm, or about 5 nm to about 50 nm, or about 10 nm to 30 nm. Periodic gaps may be formed primarily in a horizontal dimension, vertical dimension, or both. The porosity (percent of space void of solid state material) may range from 1 to 99%, but more specifically about 10%-80%, or about 30-75%. The thickness of solid state material between gaps/pores may range from 1 nm to about 50,000 nm, or about 1 nm to about 5,000 nm, or about 1 nm to about 500 nm, or about 1 nm to about 200 nm, or about 1 nm to about 50 nm, or about 5 nm to about 50 nm, or about 10 nm to 30 nm. The thickness of the pore layer (vertical depth) may range from greater than 1 micron, but more specifically from about 1 micron to 1000 microns, or about 1 micron to 500 microns, or about 1 micron to 200 microns, or about 1 micron to about 100 microns, or about 10 microns to about 100 microns, or about 30 microns to 70 microns. The index of refraction for air is about 1, while exemplary solid state materials have indexes of refraction that exceed 1, and more specifically can range from about greater than 1, or about 1.5 to 4, or about 1.5 to 3. The index of refraction of sterilizing or disinfecting liquids also can exceed 1 so as to change the wavelength at which a solid material Bragg diffracts light in the presence of a sterilizing or disinfecting liquid.

Exemplary solid state materials are described elsewhere herein.

[0050] Additionally, based on application of a sterilizing or disinfecting liquid to photonic crystal 120, that liquid - which has a third refractive index that is significantly higher than the second refractive index - can flow into, and optionally can substantially fill, gaps 123 or vertical gaps 124, 124', or 124", or both. Based on the periodicity of solid state material 121 (e.g., as defined by the respective periodicities of horizontal gaps 123 or vertical gaps 124, 124', or 124") and the first and third refractive indices, photonic crystal 120 can Bragg diffract light of a second wavelength that is distinguishable from the first wavelength, and optionally can Bragg diffract light of multiple wavelengths based on application of a sterilizing or disinfecting liquid to photonic crystal 120. For example, the periodicity of gaps 123 can Bragg diffract light of a second wavelength, and the periodicity of gaps 124, 124', or 124" can Bragg diffract light of a wavelength that is different from the second wavelength, e.g., a fifth wavelength.

[0051] For example, FIG. 2B illustrates an exemplary spectrum of wavelengths that can be Bragg diffracted by a medical surface responsive to application of a sterilizing or disinfecting liquid, according to some embodiments of the present invention. Spectrum 220 of diffracted wavelengths can be centered at a second wavelength λ₂, can have any suitable spectral shape, such as Gaussian or Lorentzian, and can have a bandwidth that can be characterized using any suitable metric, such as full-width-at-half-maximum (FWFDVI). In one nonlimiting, illustrative embodiment, second wavelength λ₂ is visible to the naked human eye. Alternatively, second wavelength λ₂ can be invisible to the naked human eye but can be detected using a suitable detector such as mentioned above. Regardless of the particular detection scheme, whether human eye or device, first wavelength λι is distinguishable from second wavelength λ₂, thus facilitating a determination that the sterilizing or disinfecting liquid has flowed into horizontal gaps 123 or vertical gaps 124, 124', or 124" and that therefore medical surface 110 is respectively sterilized or disinfected. As one nonlimiting, purely illustrative example, first wavelength λι is in the green portion of the visible spectrum, and second wavelength λ₂ is in the red portion of the visible spectrum, thus facilitating ready determination that medical device 110 is respectively sterilized or disinfected. Additionally, note that first spectrum 210 and second spectrum 220 can, but need not necessarily have the same spectral shapes as one another, and can, but need not necessarily, have the same bandwidths as one another.

[0052] One skilled in the art readily would be able to co-select the dimensions and periodicity of gaps 124 and a composition of solid state material 121 so as to Bragg diffract light of a second wavelength in the presence of a sterilizing or disinfecting liquid. In nonlimiting examples, horizontal gaps 123 or vertical gaps 124, 124', or 124" can have a dimension of about 1 nm to about 500 nm, or about 1 nm to about 200 nm, or about 1 nm to about 50 nm, or about 5 nm to about 50 nm, or about 10 nm to 30 nm; and can have a periodicity of about 1 nm to about 50,000 nm, or about 1 nm to about 5,000 nm, or about 1 nm to about 500 nm, or about 1 nm to about 200 nm, or about 1 nm to about 50 nm, or about 5 nm to about 50 nm, or about 10 nm to 30 nm. Periodic gaps may be formed primarily in a horizontal dimension, vertical dimension, or both. The porosity (percent of space void of solid state material) may range from 1 to 99%, but more specifically about 10%-80%, or about 30-75%. The thickness of the solid state material between gaps/pores may range from 1 nm to about 50,000 nm, or about 1 nm to about 5,000 nm, or about 1 nm to about 500 nm, or about 1 nm to about 200 nm, or about 1 nm to about 50 nm, or about 5 nm to about 50 nm, or about 10 nm to 30 nm. The thickness of the pore layer (vertical depth) may range from greater than 1 micron, but more specifically from about 1 micron to 1000 microns, or about 1 micron to 500 microns, or about 1 micron to 200 microns, or about 1 micron to about 100 microns, or about 10 microns to about 100 microns, or about 30 microns to 70 microns. The index of refraction for air is about 1, while exemplary solid state materials have indexes of refraction that exceed 1, and more specifically can range from about greater than 1, or about 1.5 to 4, or about 1.5 to 3. The index of refraction of sterilizing or disinfecting fluids also can be greater than 1 so as to change the wavelength at which a solid material Bragg diffracts light in the presence of a sterilizing or disinfecting liquid. Exemplary solid state materials, and exemplary sterilizing or disinfecting liquids, are described elsewhere herein.

[0053] Additionally, the sterilizing or disinfecting liquid can be removed, e.g., can evaporate, from photonic crystal 120, thus again filling gaps 123, 124, 124', or 124" with air, which has a second refractive index. Based on the vertical or horizontal periodicity of solid state material 121 (e.g., as defined by the horizontal periodicity of gaps 123 or the vertical periodicity of gaps 124, 124', 124") and the first and second refractive indices, photonic crystal 120 again can Bragg diffract light of the first wavelength, and optionally can Bragg diffract light of multiple wavelengths based on removal of the sterilizing or disinfecting liquid from photonic crystal 120. For example, the periodicity of gaps 123 again can Bragg diffract light of a first wavelength, and the periodicity of gaps 124, 124', or 124" again can Bragg diffract light of a wavelength that is different from the first wavelength, e.g., the fourth wavelength. For example, FIG. 2C illustrates an exemplary spectrum of wavelengths that can be Bragg diffracted by a medical surface after removal of a sterilizing or disinfecting liquid, according to some embodiments of the present invention. Spectrum 210 of diffracted wavelengths again can be centered at a first wavelength λ], and can have the same spectral shape and bandwidth as before the sterilizing or disinfecting liquid was applied. Based on the Bragg diffraction of light of the first wavelength again, it can be determined that medical surface 110 is ready for use.

[0054] Note that photonic crystal 120 can include any suitable material or combination of materials configured to cause Bragg diffraction of different, and distinguishable, wavelengths based on respective exposure of photonic crystal 120 to air or to application of a sterilizing or disinfecting liquid. For example, a wide variety of different types of photonic crystals are known in the art, including but not limited to those described below with reference to FIG. 4.

Additionally, photonic crystal 120 suitably can be disposed on medical surface 110 using any suitable technique. As a few nonlimiting examples, photonic crystal 120 can be self-assembled onto medical surface 110; can be painted onto medical surface 110; or can be welded to medical surface 110. In one illustrative, nonlimiting embodiment, medical surface 110 includes a first polymer, and photonic crystal 120 includes a second polymer that can be the same as, or different from, the first polymer. In another illustrative, nonlimiting embodiment, photonic crystal 120 includes an opal. In yet another, nonlimiting embodiment, photonic crystal 120 includes a substantially periodic array of pillars surrounded by air.

[0055] Alternatively, a photonic crystal can be embedded within a medical surface. For example, in the exemplary embodiment illustrated in FIG. IB, article 100' includes medical surface 110' within which photonic crystal 120' is embedded. In a manner analogous to that described above with reference to FIGS. 1 A and 2A-2C, photonic crystal 120' can Bragg diffract light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, and can Bragg diffract light of a second wavelength responsive to applying the sterilizing or disinfecting liquid. The first wavelength can be distinguishable from the second wavelength. Medical surface 110' can be respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid. Additionally, photonic crystal 120' again can Bragg diffract light of the first wavelength after removal, e.g., evaporation, of the sterilizing or disinfecting liquid, indicating that medical surface 110' is ready for use. Photonic crystal 120' can additionally, or alternatively, define vertically periodic gaps such as gaps 124, 124', or 124" described above with reference to FIGS. 1D-1F. [0056] Photonic crystal 120' can include any suitable material or combination of materials configured to cause Bragg diffraction of different, and distinguishable, wavelengths based on respective exposure of photonic crystal 120' to air or to application of a sterilizing or disinfecting liquid. For example, methods for defining photonic crystals within another material are known in the art, including but not limited to those described below with reference to FIG. 4.

Additionally, photonic crystal 120' suitably can be embedded within medical surface 110' using any suitable technique. In one nonlimiting embodiment, photonic crystal 120' is formed of the same material as is medical surface 110', and is of unitary construction with medical surface 110' . In another, nonlimiting embodiment, photonic crystal 120' includes a substantially periodic array of pillars surrounded by air. Optionally, each of the pillars defines a vertical periodicity in a manner such as described above with reference to FIGS. 1D-1F.

[0057] As yet another example, a photonic crystal can be adhered to a medical surface. For example, in the exemplary embodiment illustrated in FIG. 1C, article 100" includes medical surface 110" to which material 125 is adhered via suitable adhesive (not specifically illustrated). Photonic crystal 120" can be disposed on, or embedded within, material 125. In a manner analogous to that described above with reference to FIGS. 1 A and 2A-2C, photonic crystal 120" can Bragg diffract light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, and can Bragg diffract light of a second wavelength responsive to applying the sterilizing or disinfecting liquid. The first wavelength can be distinguishable from the second wavelength. Medical surface 110" can be respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid. Additionally, photonic crystal 120" again can Bragg diffract light of the first wavelength after removal, e.g., evaporation, of the sterilizing or disinfecting liquid, indicating that surface 110" is ready for use. Photonic crystal 120' can additionally, or alternatively, define vertically periodic gaps such as gaps 124, 124', or 124" described above with reference to FIGS. 1D-1F.

[0058] Photonic crystal 120" can include any suitable material or combination of materials configured to cause Bragg diffraction of different, and distinguishable, wavelengths based on respective exposure of photonic crystal 120" to air or to application of a sterilizing or disinfecting liquid. For example, methods for disposing photonic crystals on another material, or embedding photonic crystals within another material, are known in the art, including but not limited to those described below with reference to FIG. 4. An adhesive can be applied to such a material so as to define a sticker 125, 120" that suitably can be applied to medical surface 110". Optionally, sticker 125, 120" can be periodically replaced. In one nonlimiting embodiment, material 125 on which photonic crystal 120" is disposed or in which photonic crystal 120" is embedded includes a polymer. In one illustrative, nonlimiting embodiment, medical surface 110" includes a first polymer, and photonic crystal 120" includes a second polymer that can be the same as, or different from, the first polymer. In another illustrative, nonlimiting

embodiment, photonic crystal 120" includes an opal. In yet another, nonlimiting embodiment, photonic crystal 120" includes a substantially periodic array of pillars surrounded by air.

Optionally, each of the pillars defines a vertical periodicity in a manner such as described above with reference to FIGS. ID- IF.

[0059] As noted elsewhere herein, photonic crystals 120, 120', 120" and respective medical surfaces 110, 110', 110" can include any suitable material or combination of two-dimensionally or three-dimensionally periodic materials. For example, in some embodiments, one or both of photonic crystals 120, 120', 120" and medical surfaces 110, 110', 110" independently can include a relatively optically dark or optically opaque polymer or other material, a relatively optically light or optically transparent polymer or other material, or an optically colorful polymer or other material. For example, the photonic crystal can include an optically transparent polymer or other optically transparent material and the medical surface can include an optically light polymer or other optically light material. Or, for example, the photonic crystal can include an optically transparent polymer or other optically transparent material and the medical surface can include an optically dark polymer or other optically dark material. Or, for example, the photonic crystal can include an optically transparent polymer or other optically transparent material, and the medical surface can include an optically colorful polymer or other optically colorful material. In one nonlimiting example, the photonic crystal can have a different refraction gradient than does the medical surface.

[0060] Some nonlimiting examples of polymers, e.g., thermally moldable polymers, and other moldable materials that one or both of photonic crystals 120, 120', 120" and medical surfaces 1 10, 110', 110" independently can include, or independently can consist essentially of, are listed in Table 1. Such materials are anticipated to be compatible with porous silicon templating and nanoimpnnt lithography techniques such as described in greater detail herein and in certain of the references cited herein, or otherwise known in the art.

Table 1

Acetal Copolymer, Natural (Celcon M90 CF2001) Resin

Acetal Homopolymer, Black (Delrin 500P

BK602) Resin

Acetal Homopolymer, Natural (Delrin 5 OOP

NCOIO) Resin

Acrylic (PMMA), Clear (Plexiglas V052-100) Resin

Engineered Thermoplastic Polyurethane

(ETPU), Natural (Isoplast 202EZ) Resin

High Density Polyethylene (HDPE), Natural

(Unipol DMDA 8007) Resin

HDPE, Natural (Marlex 9006 HID) Resin

Liquid Crystal Polymer (LCP), Black 30%

Glass Fiber (Vectra E130ID-2 VD3005 Black

Al) Resin

Low Density Polyethylene (LDPE), Fern

Green 3% (UN66070) (Dow LDPE 722) Resin

LDPE, Natural (Dow LDPE 722) Resin

LLDPE, Natural (Dowlex 2517) Resin

Nylon 6, Natural 15% Glass Fiber (Zytel

73G15L NCOIO) Resin

Nylon 6/12, Black 33% Glass Fiber (Zytel

77G33L BK031) Resin

Nylon 66, Black (RTP 200 200 UV) Resin

Nylon 66, Black (Zytel 101L BKB009) Resin

Nylon 66, Black (Hylon Select NIOOOEHL) Resin

Nylon 66, Natural (Zytel 103 HSL NCOIO) Resin

Nylon 66, Black 13% Glass Fiber (Zytel

70G13 HS1L BK031) Resin Nylon 66, Black 13% Glass Fiber (Hylon Select N1013HL) Resin

Nylon 66, Natural 13% Glass Fiber (Zytel

70G13 HS1L NC010) Resin

Nylon 66, Black 14% Glass Fiber (Zytel

8018HS BKB085) Resin

Nylon 66, Natural 14% Glass Fiber (Zytel

80G14AHS NCOIO) Resin

Nylon 66, Black 20% Glass Fiber (RTP 200

203 FR) Resin

Nylon 66, Black 33% Glass Fiber (Zytel

70G33 HS1L BK031) Resin

Nylon 66, Black 33% Glass Fiber (Vydyne

R533H) Resin

Nylon 66, Black 33% Glass Fiber (Hylon

Select N1033HL) Resin

Nylon 66, Natural 33% Glass Fiber (Zytel

70G33 HSIL NCOIO) Resin

Nylon 66, Black 40% Mineral Reinforced

(Minion 10B40 BK061) Resin

Nylon 66, Black Impact Modifier, Rubber

(Zytel ST-801 BK010) Resin

Nylon 66, Natural Impact Modifier, Rubber

(Zytel ST-801 NCOIO) Resin

Polybutylene Terephthalate (PBT), Black

(Valox 357-BK1066) Resin

PBT, Black (Crastin S600F20 BK851 (same as S610)) Resin

PBT, Black (Valox 364-BK1066) Resin

PBT, Natural (Valox 357-1001) Resin PBT, Black 30% Glass Fiber (Valox 420SEO- BK1066-BG) Resin

PBT, Natural 30% Glass Fiber (Valox 420

SEO 1001 Nat) Resin

Polycarbonate (PC), Black (Lexan 940-701) Resin

PC, Black (Makrolon 2405-901510) Resin

PC, Black (Hylex P1025L) Resin

PC, Blue Tint (Makrolon RX2530-451118) Resin

PC, Clear (Makrolon 2407-550115) Resin

PC, Clear (Makrolon 2458-550115) Resin

PC, Infrared (Lexan 121 S-80362) Resin

PC, Smoke (RTP 300 399X71833 S-94450) Resin

PC, Natural 10% Glass Fiber (RTP 300 301) Resin

PC, Natural 20% Glass Fiber (Lexan 3412R- 131) Resin

PC/PBT, Black (Xenoy 6620-BK1066) Resin

Polyethylene Terephthalate (PET), Black 30%

Glass Fiber (Rynite 530-BK503) Resin

PET, Black 35% Glass Mica Low Warp

(Rynite 935 BK505) Resin

Poly(Ethylene Terephthalate)-Glycol PETG,

Clear (Eastar 6763) Resin

Polypropylene (PP), Natural (RTP Anti-static

Permastat 100) Resin

PP Homopolymer, Black (Maxxam FR PP

301BLK1284-11 S) Resin

PP Homopolymer, Natural (Prof ax 6323) Resin

PP Homopolymer, Natural (Profax 6523) Resin

PP Random Copolymer, Natural (FHR PP

P5M6K-048) Resin Polyphthalamide (PPA), Natural 35% Glass Fiber (Zytel HTN 51G35HSL NCOIO) Resin

Polyphenyl Ether (PPE)/Polystyrene (PS),

Black (Noryl 731-701) Resin

Poly (p-Phenylene Sulfide) (PPS), Black 40%

Glass Fiber (Ryton R-4-02) Resin

PPS, Natural 40% Glass Fiber (Ryton R-4) Resin

PS (General Purpose Polystyrene) (GPPS),

Clear (Styron 666D) Resin

PS (High Impact Polystyrene) (HIPS), Dove

Grey 3% (UN7378) (Styron 498) Resin

PS (HIPS), Natural (Styron 498) Resin

Polysulfone (PSU), Natural (Udel P-3703 NT

11) Resin

Styrene-Butadiene (SB), Clear (K-Resin

KR01K CPC BDS CL) Resin

Thermoplastic Elastomer (TPE), Black

(Santoprene 111-35) Resin

TPE, Black (Santoprene 111-45) Resin

TPE, Black (Santoprene 101-64) Resin

TPE, Natural (Santoprene 211-45) Resin

TPE, Natural (Santoprene 251-70W232) Resin

TPE, Natural (Santoprene 201-64) Resin

Thermoplastic Polyurethane (TPU)-Polyester, Natural (Texin 245) Resin

TPU-Poly ether, Natural (Texin 983-000000) Resin

Thermoplastic Vulcanizate (TPV), Black

(Santoprene 101-87) Resin

TPV, Black (Santoprene 101-55) Resin

TPV, Black (Santoprene 101-73) Resin Poly ether Ether Ketone (PEEK), Natural

(Victrex 450G) High-Temp Resin

PEEK, Natural 30% Glass Fiber (Vestakeep

4000 GF30) High-Temp Resin

Polyethyenimine (PEI), Black (Ultem 1000- 7101) High-Temp Resin

PEI, Natural (Ultem 1000-1000) High-Temp Resin

PEI, Black 30% Glass Fiber (Ultem 2300 - 7301) High-Temp Resin

PEI, Natural 30% Glass Fiber (Ultem 2300 - 1000) High-Temp Resin

Magnesium, Grey (Magnesium AZ-91) Thixo

Metal Injection Molding (MFM) Stainless Steel

(Catamold 17-4 PH K) MFM

MIM Stainless Steel (Catamold 316L K) MFM

Silicone, Clear (Elastosil 3003/50 A/B) Liquid Silicone Rubber (LSR)

Silicone, Clear (Elastosil 3003/30 A/B) LSR

Silicone, Clear (Elastosil 3003/70 A/B) LSR

[0061] Photonic crystals 120, 120', 120" suitably can indicate sterilization or disinfection of medical surfaces 110, 110', 110", respectively," responsive to application of any suitable respective sterilizing or disinfecting liquid.

[0062] Some nonlimiting examples of sterilizing or disinfecting liquids that potentially can be suitable for use with photonic crystals 120, 120', 120" and medical surfaces 110, 110', 110" include liquids including glutaraldehyde, e.g., at least 2.4% glutaraldehyde; liquids including a mixture of glutaraldehyde and phenol or phenate, e.g., at least 0.95% glutaraldehyde and at least 1.64%) phenol/phenate; liquids including hydrogen peroxide, e.g., at least 7.5% stabilized hydrogen peroxide; liquids including a mixture of hydrogen peroxide and peracetic acid, e.g., at least 7.35%) hydrogen peroxide with at least 0.23% peracetic acid, or at least 0.08%> peracetic acid with at least 1.0% hydrogen peroxide; liquids including peracetic acid, e.g., at least 0.2% peracetic acid; liquids including ethanol, e.g., at least 30% ethanol (for disinfection) or at least 70% ethanol (for sterilization); liquids including isopropanol, e.g., at least 20% isopropanol (for disinfection) or at least 90% isopropanol (for sterilization); liquids including at least 0.55% ortho-phthalaldehyde; liquids including bleach, e.g., at least 5.25% household bleach, e.g., 5.25%-6.15%; commercially available phenolic germicidal detergent solution; commercially available iodophor germicidal detergent solution; commercially available quaternary ammonium germicidal detergent solution; Milton sterilizing fluid (aqueous 1% sodium hypochlorite and 16.5%) sodium chloride, diluted to about 1 :80 for sterilization; commercially available from Milton BabyCare, Newmarket, United Kingdom); superoxidized water, such as described in Rutala et al., "New Disinfection and Sterilization Methods," Emerging Infectious Diseases 7(2): 348-353 (2001), the entire contents of which are incorporated by reference herein; water with dissolved ozone, such as described in THEROZONE® product sheet, TherOzone USA, Inc., Santa Monica, California, 2 pages (2012), the entire contents of which are incorporated by reference herein; liquids including performic acid; liquids including ortho-phthalaldehyde, such as described in Rutala et al., "New Disinfection and Sterilization Methods," Emerging Infectious Diseases 7(2): 348-353 (2001), e.g., at least 0.21% ortho- phthalaldehyde; and liquids including peracetic acid. For further details and examples of sterilizing or disinfecting liquids, see Rutala et al., "Guideline for Disinfection and Sterilization in Health care Facilities, 2008," and Rutala et al., "New Disinfection and Sterilization Methods," Emerging Infectious Diseases 7(2): 348-353 (2001). Any other suitable sterilizing or disinfecting liquid can be used.

[0063] Factors that can affect the efficacy of both disinfection and sterilization include prior cleaning of the object; organic and inorganic load present; type and level of microbial contamination; concentration of and exposure time to the germicide; physical nature of the object (e.g., crevices, hinges, and lumens); presence of biofilms; temperature and pH of the disinfection or sterilization process; and in some cases, relative humidity of the sterilization process.

"Cleaning" refers to the removal of visible soil (e.g., organic and inorganic material) from a surface and can be accomplished manually or mechanically using water with detergents or enzymatic products. Thorough cleaning is particularly useful before high-level disinfection and sterilization because inorganic and organic materials that remain on a surface can interfere with the effectiveness of these processes. "Decontamination" removes pathogenic microorganisms from surfaces so they are safe to handle, use, or discard. [0064] Additionally, at least the sidewalls of photonic crystals 120, 120', 120" optionally can be functionalized so as to enhance wetting of the sterilizing or disinfecting liquid into the horizontal gaps between the sidewalls or the vertical gaps defined by the sidewalls. By

"functionalized" it is meant that one or more chemical moieties are coupled to a surface, such as a sidewall of a photonic crystal. Methods of selecting chemical moieties so as to enhance wetting of a desired liquid, and methods of coupling such chemical moieties to a desired surface, are well known. As one example, a variety of different moieties that suitably can be attached to respective polymer surfaces, or other modifications of polymer surfaces, are described in Penn et al., "Chemical Modification of Polymer Surfaces: A Review," Polymers for Advanced

Technologies, 5: 809-817 (1994), the entire contents of which are incorporated by reference herein. As another example, poly(methylmethacrylate) Zeonor 1060R and Zeonex E48R have been identified as promising candidates for which surface modification, such as described in Diaz-Quijada et al., "Surface modification of thermoplastics - towards the plastic biochip for high throughput screening devices," Lab Chip, 7: 856-862 (2007), the entire contents of which are incorporated by reference herein.

[0065] In one illustrative embodiment, the functionalization enhances wetting of the photonic crystal by the sterilizing or disinfecting liquid selectively relative to at least one other liquid, e.g., as described in Hansson et al., "Hydrophobic pore array surfaces: Wetting and interaction forces in water/ethanol mixtures," Journal of Colloid and Interface Science 396: 278-286 (April 15, 2013), the entire contents of which are incorporated by reference herein. It is anticipated that by controlling the surface chemistry (e.g., hydrophobicity, hydrophilicity, or charge), the pore density, and the periodicity of the photonic crystal, one can effectively control the wettability of the photonic crystal's void space (e.g., pores) for a variety of fluid compositions to which it can be exposed. As one example, based upon the sidewalls defining the pores being relatively hydrophobic, it would be expected that air can preferentially penetrate the pores relative to water. Likewise, based upon the sidewalls defining the pores being relatively hydrophilic, it would be expected that water can preferentially penetrate the pores relative to air. By employing appropriate surface chemistries so as to tailor the level of hydrophobicity, hydrophilicity, charge, or the like, it is anticipated that the photonic crystal can be chemically modified in a way that would allow specific sterilizing or disinfecting fluids to be distinguished from one another, e.g., so as to distinguish water from 70% ethanol/water or so as to distinguish water from a surfactant based disinfectant.

[0066] Exemplary materials that can be disposed on the sidewalls of the photonic crystal 120, 120', or 120" so as to functionalize the sidewalls are provided below in Table 2, and other exemplary moieties that can be disposed on the sidewalls of the photonic crystal 120, 120', or 120" so as to functionalize the sidewalls are provided below in Table 3.

Table 2

Environmentally Surface molecule that changes by PH sensitive bond, light sensitive polymer its environment (e.g. acid) sensitive bond, heat

sensitive bond, enzyme sensitive bond, hydrolytic bond

Hydrogel Polymer with high hydrophilicity Synthetic 2-hydroxyethyl and water "ordering" capacity metacrylate (HEMA)-based, polyethylene glycol (PEG)- based, PLGA, PEG- di aery late; Natural ionic gels, alginate, gelatin, hyaluronic acids, fibrin

Metal Thin metal coating to achieve Gold, silver, nickel, copper, improved resonance and/or platinum, titanium, functionalization capacity chromium, palladium

Semiconductors Semiconductor layer or core that Silicon and galadium

enhance Plasmon resonance

Polymer containing a Fluorophore cross linked to a Fluorescein, rhodamine, fluorescent marker polymer coat or directly to the Cy5, Cy5.5, Cy7, Alexa surface of the particle dyes, Bodipy dyes

Matrix Matrix coating that increases Silica, polyvinyl

solubility of nanoparticles and/or pyrrolidone, polysulfone, reduces "stickiness" to biological polyacrylamide,

structures polyethylene glycol,

polystyrene cellulose, pplyquaterniums, lipids, surfactants, carbopol

Table 3

Class of Moiety Properties Examples of Moieties

Polar moieties Neutral charge but increases Hydroxyl groups,

hydrophilicity in water isothiocyanates

Non-polar moieties Increases hydrophobicity and or Hydrocarbons, myristoylated improves solubility compounds, silanes,

isothiocyanates

Charged moieties Functional surface modifications Amines, carboxylic acids, that change the zeta potential, hydroxyl s

isoelectric point, or pKa, and

impact adsorption / binding to

complementary charge

compounds

Ionic moieties Surface groups that have a single Ammonium salts, chloride ion salts

Basic moieties Groups that donate a hydrogen Amides, hydroxides, metal ions oxides, fluoride

structure on the target

[0067] Methods of functionalizing the sidewalls of photonic crystal 120, 120', or 120" can follow widely established surface chemistry procedures, including but not limited to:

salinization, layer-by-layer deposition, chemical vapor deposition, plasma enhanced chemical vapor deposition, reactive ion etching, plasma cleaning, chemical etching (acid, base, liquid, or vapor), epoxide chemistry, polymerization chemistry, click chemistry, or other conjugation or bioconjugation techniques known in the art.

[0068] In yet another nonlimiting embodiment, photonic crystal 120, 120', or 120" is functionalized so as to include a photoactive material, such as a chromophore or a plasmonic nanoparticle. A chromophore is able to selectively absorb a chosen wavelength of light, thereby enhancing effectiveness of radiation, such as laser light.

Exemplary Methods for Sterilizing or Disinfecting Medical Surfaces

[0069] Medical surfaces that include photonic crystals suitably can be sterilized or disinfected, and suitably can indicate such sterilization or disinfection, using any suitable method. FIG. 3 illustrates steps in an exemplary method for sterilizing or disinfecting a medical surface, according to some embodiments of the present invention. However, it should be appreciated that the present medical surfaces suitably can be used with other sterilization or disinfection methods.

[0070] Method 300 illustrated in FIG. 3 includes providing a medical surface including a photonic crystal (310). For example, as described above with reference to FIGS. 1A-1C, an article (e.g., article 100, 100', or 100") can include a respective medical surface (e.g., medical surface 110, 110', or 110"). A photonic crystal (e.g., photonic crystal 120, 120', or 120") can be disposed on or embedded within the respective medical surface. For example, the photonic crystal can be adhered to, self-assembled onto, painted onto, or welded to the medical surface, e.g., using methods such as described below with reference to FIG. 4. Optionally, at least the sidewalls of the photonic crystal can be functionalized so as to enhance wetting of a sterilizing or disinfecting liquid. In one illustrative embodiment, the functionalization enhances wetting of the photonic crystal by the sterilizing or disinfecting liquid selectively relative to at least one other liquid. Methods of functionalizing the surface of the photonic crystal (e.g., photonic crystal 120, 120', or 120") can follow widely established surface chemistry procedures, including but not limited to: salinization, layer-by-layer deposition, chemical vapor deposition, plasma enhanced chemical vapor deposition, reactive ion etching, plasma cleaning, chemical etching (acid, base, liquid, or vapor), epoxide chemistry, polymerization chemistry, click chemistry, or other conjugation or bioconjugation techniques known in the art. The surfaces of the photonic crystal, e.g., the sidewalls of the photonic crystal, can be fully functionalized, partial

functionalized, or non-functionalized.

[0071] Method 300 illustrated in FIG. 3 also includes, responsive to exposure to air in the absence of a sterilizing or disinfecting fluid, Bragg diffracting light of a first wavelength by the photonic crystal (320). For example, as described above with reference to FIGS. 1 A-IC, a solid- state material defining photonic crystals 120, 120', or 120" can have a first refractive index, and air within horizontal gaps 123 or vertical gaps 124, 124', 124" defined by sidewalls of such solid-state material can have a second refractive index. Accordingly, photonic crystals 120, 120', or 120" can Bragg diffract a spectrum of wavelengths that includes a first wavelength, e.g., spectrum 210 including first wavelength λι such as described above with reference to FIG. 2 A, based upon the first refractive index, the second refractive index, and the periodicity of the photonic crystal. [0072] Method 300 illustrated in FIG. 3 also includes applying a sterilizing or disinfecting liquid to the photonic crystal (330). As described above with reference to FIGS. 1 A-1C, the sterilizing or disinfecting liquid can flow into the horizontal or vertical gaps defined by the sidewalls of photonic crystals 120, 120', or 120". In embodiments in which the sidewalls of the photonic crystal are functionalized, such functionalization can enhance wetting, and thus flow, of the sterilizing or disinfecting liquid into the horizontal or vertical gaps. Exemplary sterilizing or disinfecting liquids are provided elsewhere herein or otherwise are known in the art.

[0073] Method 300 illustrated in FIG. 3 also includes, responsive to application of the sterilizing or disinfecting liquid, Bragg diffracting light of a second wavelength by the photonic crystal, the first wavelength being distinguishable from the second wavelength (340). For example, as described above with reference to FIGS. 1 A-1C, a solid-state material defining photonic crystals 120, 120', or 120" can have a first refractive index, and the sterilizing or disinfecting liquid that flows into the horizontal or vertical gaps defined by the sidewalls of such solid-state material can have a third refractive index. Accordingly, photonic crystals 120, 120', or 120" can Bragg diffract a spectrum of wavelengths that includes a second wavelength, e.g., spectrum 220 including second wavelength λ₂ such as described above with reference to FIG. 2B, based upon the first refractive index, the third refractive index, and the periodicity of the photonic crystal.

[0074] Method 300 also includes, based on the Bragg diffraction of the light of the second wavelength, determining that the medical surface is sterilized or disinfected (350). For example, the second wavelength can be distinguished from the first wavelength, e.g., using the human eye or a suitable detector. Based on such distinction, it can be determined that the sterilizing or disinfecting liquid has flowed into the horizontal or vertical gaps defined by the sidewalls of the photonic crystal, and that the medical surface therefore has been sterilized or disinfected.

[0075] Optionally, method 300 also can include evaporating the sterilizing or disinfecting liquid from the photonic crystal, and responsive to removal, e.g., evaporating, of the sterilizing or disinfecting liquid, again Bragg diffracting light of the first wavelength by the photonic crystal. For example, as described above with reference to FIGS. 1 A-1C, such removal, e.g.,

evaporation, can cause air to again fill the horizontal or vertical gaps defined by sidewalls of the solid-state material of photonic crystal 120, 120', or 120", and therefore the photonic crystal can Bragg diffract a spectrum of wavelengths that includes a first wavelength, e.g., spectrum 210 including first wavelength λι such as described above with reference to FIG. 2C, based upon the first refractive index, the second refractive index, and the periodicity of the photonic crystal. Based on the Bragg diffraction of the light of the first wavelength again, it can be determined that the medical surface is ready for use.

[0076] Note that method 300 is compatible with any suitable medical surface that includes a photonic crystal. In one illustrative, nonlimiting embodiment, the medical surface includes a first polymer, and the photonic crystal includes a second polymer that can be the same as, or different from, the first polymer. In another illustrative, nonlimiting embodiment, the photonic crystal includes an opal. In yet another, nonlimiting embodiment, the photonic crystal includes a substantially periodic array of pillars surrounded by air. Other exemplary embodiments are described elsewhere herein, e.g., below with reference to FIG. 4. Additionally, method 300 is compatible with any suitable medical surface that defines at least a portion of an article, such as a medical device, a tray, a medical drape, or a floor, wall, counter, or door of a health care facility. Other suitable medical surfaces and articles readily may be envisioned.

Exemplary Methods for Making Medical Surfaces Indicating Sterilization or Disinfection

[0077] Medical surfaces that indicate sterilization or disinfection can be formed using any suitable method. For example, FIG. 4 illustrates steps in an exemplary method for making a medical surface indicating sterilization or disinfection, according to some embodiments of the present invention. It should be appreciated that other methods of making medical surfaces that indicate sterilization or disinfection readily can be used.

[0078] Method 400 illustrated in FIG. 4 includes providing a medical surface (410).

Illustratively, the medical surface can define at least a portion of an article, such as a medical device, a tray, a medical drape, or a floor, wall, counter, or door of a health care facility. Other suitable medical surfaces and articles readily may be envisioned. [0079] Method 400 illustrated in FIG. 4 also includes coupling a photonic crystal to the medical surface (410). For example, the photonic crystal can be disposed on or embedded within the medical surface using any suitable method.

[0080] In some embodiments, the photonic crystal can be formed using a method analogous to that described in U.S. Patent No. 7,713,778 to Li, the entire contents of which are incorporated by reference herein. According to Li, a silicon substrate is provided; a porous silicon template is created from the silicon substrate, wherein the template is created to have a predetermined configuration; a predetermined material is deposited on the porous silicon template; and the porous silicon template is removed from the deposited material to leave a freestanding nanostructure. It is anticipated that methods such as described in Li suitably can be adapted so as to bring a medical surface or a sticker into contact with a porous silicon template, in a manner analogous to depositing a predetermined material on a porous silicon template as is disclosed in Li, and to remove the porous silicon template from the medical surface or sticker to leave a freestanding nanostructure, in a manner analogous to removing the porous silicon template from the deposited material as is disclosed in Li. In embodiments in which the nanostructure is disposed on or defined in a sticker, the sticker can be applied to any suitable medical surface.

[0081] In other embodiments, the photonic crystal can be formed using a method analogous to that described in U.S. Patent No. 8,206,780 to Li, the entire contents of which are incorporated by reference herein. According to Li, a porous photonic material layer is prepared; a soluble polymer is patterned on the porous photonic material layer, leaving dividing portions of the material layer untreated; the polymer is infused into the material layer; and the dividing portions of the material are removed to obtain the photonic particles. In one embodiment, the photonic particles can be attached to the surface of a medical device or the outer surface of an adhesive sticker. For metallic surfaces, this can be achieved by use of adhesives, resins, or chemical coupling. For polymer surfaces, this can be achieved by use of adhesives, resins, chemical coupling, or by embedding the photonic particles in a host material by first thermally softening the host material followed by forcing the photonic particles into the material via applied pressure in a manner analogous to that described in U.S. Patent No. 8,206,780. For the production of adhesive stickers, the photonic particles can be directly attached or embedded in a thin polymer film with an adhesive backing. [0082] For further details on other exemplary methods of forming porous silicon templates, see the following references, the entire contents of each of which are incorporated by reference herein: Benecke et al., "MEMS Applications of Porous Silicon," Proc. SPIE 4592, Device and

Process Technologies for MEMS and Microelectronics II, 76 (November 21, 2001);

doi: 10.1117/12.449009; and Sailor, Porous Silicon in Practice: Preparation, Characterization and

Applications, First Edition, Chapter 1, pages 1-42, Wiley- VCH Verlag GmbH & Co. KGaA

(2012).

[0083] Note that porous silicon templates formed using methods such as described in U.S. Patent No. 7,713,778 to Li, U.S. Patent No. 8,206,780 to Li, Benecke, and Sailor suitably can include sidewalls that are periodically horizontally arranged such as described above with reference to FIGS. 1 A-1C, and that also define periodically vertically arranged features such as described above with reference to FIGS. 1D-1F.

[0084] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in U.S. Patent Publication No. 2010/0120116 to Kaplan, the entire contents of which are incorporated by reference herein. According to Kaplan, a method of manufacturing a nanopatterned biopolymer optical device includes providing a biopolymer; processing the biopolymer to yield a biopolymer matrix solution; providing a substrate with a nanopatterned surface; casting the biopolymer matrix solution on the nanopatterned surface of the substrate; and drying the biopolymer matrix solution to form a solidified biopolymer film on the substrate, where the solidified biopolymer film is formed with a surface having a nanopattern thereon. Through proper control over feature size, periodicity, and surface chemistry of the casted nanopatterned biopolymer surfaces that exhibit Bragg diffraction of distinguishable wavelengths (e.g., such as described above with references to FIGS. 2A-2C) prior to, during, and after removal of a sterilizing or disinfecting liquid can be directly printed onto the surfaces of medical devices or adhesive stickers.

[0085] In still other embodiments, the photonic crystal can be formed using any suitable method described in Fenzyl et al., "Photonic Crystals for Chemical Sensing and Biosensing," Angewandte Chemie International Edition, 53 :2-21 (2014), the entire contents of which are incorporated by reference herein, as well as references cited therein. For example, according to Fenzyl, photonic crystals that are periodic in one dimension are known as Bragg reflectors or Bragg stacks, which reflect one specific wavelength and usually have a smooth surface like a mirror, and typically are produced by techniques such as layer-by-layer deposition, multiple spin coating, or photolithography. According to Fenzyl, photonic crystals that are periodic in two dimensions are primarily produced by complex top-down methods such as photolithography and etching techniques such as described in Ge et al, Angewandte Chemie International Edition, 123 : 1530-1561 (2011) and Angewandte Chemie International Edition, 50: 1492-1522 (2011), the entire contents of both of which are incorporated by reference herein. According to Fenzyl, the form, order, size, and defects of the nanostructures can be varied to manipulate their properties. According to Fenzyl, other researchers have studied two-dimensional arrays on a hydrogel support/matrix for use in sensing, and that such studies include vertical spreading of two- dimensional array Debye ring diffraction for protein recognition, the simulation of the Langevin dynamics of three-dimensional colloidal crystal vacancies and phase transitions, the fabrication of large-area two-dimensional colloidal crystals, and the enhancement of the reflectivity of the monolayer diffraction in a two-dimensional dielectric particle array. According to Fenzyl, three- dimensional photonic crystals display periodicity in three dimensions, and include opals and inverse opals. Also according to Fenzyl, there are several top-down as well as several chemical bottom-up methods to produce three-dimensional photonic crystals, including self-assembly of nanoscopic, monodisperse spheres into a photonic crystal host, where the spheres typically include silica, zinc oxide, titanium dioxide, or organic polymers such as polystyrene or poly(methyl methacrylate) (PMMA). Also according to Fenzyl, common methods for assembly that lead to a three-dimensional arrangement utilize particle properties such as electrostatic repulsion or magnetism as well as inertial forces and capillary interactions. In some

embodiments, medical surfaces or stickers can be modified to have photonic crystals by performing layer-by-layer deposition or spin coatings in the presence of masks or application of self-assembling nanoscopic, monodisperse spheres onto the surface. Alternatively,

photolithography or etching can be used to pattern photonic crystals directly on the medical surfaces or sticker or a coating that has been placed thereon. In yet other embodiments, stickers or medical surfaces can be molded into a photonic crystal by applying heat or pressure on a photonic crystal mold (e.g., a porous silicon mold) or injecting a pre-polymer mixture into a photonic crystal mold, or combinations of both. [0086] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in Lee et al., "Scalable Nanopillar Arrays with Layer-by-Layer Patterned Overt and Covert Images," Advanced Materials, 26: 6119-6124 (2014), the entire contents of which are incorporated by reference herein. According to Lee, nanopillars were initially produced on silicon wafers by standard photolithography followed by dry etching; the resulting nanopillars were thermally oxidized and etched so as to reduce their diameters.

According to Lee, polymer including polyurethane acrylate and NOA63 adhesive as 7:3 (v/v) was casted over the nanopillars and then removed. This technique potentially can facilitate the transfer of photonic crystals in the form of nanopillar arrays onto a variety of substrates, including fabric, paper, and metals via intermolecular bonds. Optionally, by locally altering the surface chemistry and thus the wettability of the sidewalls of the nanopillar array photonic crystal, the photonic crystal can be tailored to allow selective signaling via a distinguishable shift in the Bragg diffraction triggered by an index of refraction change when the sterilizing or disinfecting liquid replaces air within the crystal. As this process allows printing onto a wide range of different surface types, it is anticipated to be usable so as to produce photonic crystals directly onto the surfaces of articles as well as being translated directly into an adhesive sticker embodiment. Additionally, Lee et al. also demonstrates that the nanopillar array photonic crystal maintains its structure, flexibility, and wettability even after rubbing with various materials, including a finger, a brush, and fabrics. As such, it is anticipated that applying methods such as described in Lee to the present medical surfaces or stickers can provide a relatively robust photonic crystal that can undergo multiple applications of a sterilizing or disinfecting liquid, e.g., via a gloved hand, swab, or fabric wipe.

[0087] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in Boldov et al., "Optical Sensors Based on Opal Film and Silica Nanoparticles Modified with a Functional Dye," Advances in Chemical Sensors, pages 29-46 (2012), Prof. Wen Wang (Ed.), ISBN: 978-953-307-792-5, InTech, available from:

www.intechopen.com/books/advances-in-chemical-sensors/optical-sensors-based-on-opal-film- and-silica-nanoparticles-modified-with-a-functonal-dye, the entire contents of which are incorporated by reference herein. According to Boldov, photonic crystal films were grown by the movable meniscus method from a suspension of monodisperse spherical particles of Si0₂ on glass prisms. Additionally, according to Boldov, monolayer opal films, which had a domain structure, were deposited by the method of short-term immersion of a prism into a suspension. It is anticipated that methods such as described in Boldov suitably can be modified so as to grow photonic crystal films onto a medical surface or sticker, e.g., the movable meniscus method or by short-term immersion of a medical surface or sticker into a suspension.

[0088] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in Pernice et al., "Opals infiltrated with a stimuli-responsive hydrogel for ethanol vapor sensing," Optics Materials Express, 3(11): 1820-1833 (2013), the entire contents of which are incorporated by reference herein. According to Pernice, a number of different techniques have been developed to obtain self-assembled structures, such as

sedimentation, cell confinement, vertical deposition, Langmuir-Blodgett, shear induced, motor drawing, air-water interface, spin-coating, and wedge cell. Pernice discloses fabricating infiltrated opals using a two step process, in which a crystalline colloidal array was obtained through self-assembly of monodisperse polystyrene nanoparticles to form a face centered cubic lattice that subsequently was infiltrated with ethanol-responsive hydrogel precursors that were then crosslinked via UV photo-polymerization. According to Pernice, the hydrogel included three monomers: 2-hydroxyethyl methacrylate, acrylic acid, and poly-ethylene glycol.

[0089] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in Lan et al., "Nanoimprint Lithography," Lithography, pages 457- 494 (2010), Michael Wang (Ed.), ISBN: 978-953-307-064-3, InTech, available from:

www.intechopen.com/books/lithography/nanoimprint-lithography, the entire contents of which are incorporated by reference herein. According to Lan, nanoimprint lithography includes two fundamental types, hot embossing lithography and UV-based nanoimprint lithography, as well as many different variations such as roll imprint process, laser-assisted direct imprint, reverse imprint lithography, substrate conformal imprint lithography, and ultrasonic nanoimprint lithography. According to Lan, nanoimprint lithography is based on the principle of

mechanically modifying a thin polymer film using a template containing a micro/nanopattern, in a thermo-mechanical or UV curing process. It is anticipated that a medical surface or sticker analogously suitably can be mechanically modified using a template containing a

micro/nanopattern, in a thermo-mechanical or UV curing process such as described in Lan. Other exemplary methods of performing nanoimprint lithography that are potentially suitable for such a use are disclosed in the following references, the entire contents of each of which are incorporated by reference herein: Francone, "Materials and anti-adhesive issues in UV-NIL," Materials, Institut National Polytechnique de Grenoble - INPG, 2010, English <tel-0066073>, 140 pages; Kooy et al., "A review of roll-to-roll nanoimprint lithography," Nanoscale Research Letters, 9:320, pages 1-13 (2014); and Smith et al., "Repurposing Blu-ray movie disks as quasi- random nanoimprinting templates for photon management," Nature Communications, 5:5517, pages 1-5 (2014).

[0090] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in Leung et al., "Light Management with Nanostructures for

Optoelectronic Devices," Journal of Physical Chemistry Letters, 5: 1479-1495 (2014), the entire contents of which are incorporated by reference herein. According to Leung, many different types of nanostructures such as nanowires, nanopillars, nanopencils, nanocones, nanoshells, nanodomes, and the like have been developed. It is anticipated that such nanostructures suitably can be adapted for use as a template for use in nanoimprint lithography. Other nanostructures that are potentially suitable for such a use are disclosed in the following references, the entire contents of each of which are incorporated by reference herein: Brongersma et al., "Light management for photovoltaics using high-index nanostructures," Nature Materials, 13 : 451-460 (2014); and Si et al., "Fabrication and characterization of well-aligned plasmonic nanopillars with ultrasmall separations," Nanoscale Research Letters, 9:299, pages 1-7 (2014).

[0091] In still other embodiments, the photonic crystal can be formed using a method analogous to that described in Ryckman et al., "Direct Imprinting of Porous Substrates: A Rapid and Low-Cost Approach for Patterning Porous Nanomaterials," Nano Letters, 11(5): 1857-1862 (2011), the entire contents of which are incorporated by reference herein. According to

Ryckman, the process utilizes reusable stamps with micro- and nanoscale features that are applied directly to a porous material to selectively compress or crush the porous network, and the stamp pattern is transferred to the porous material with high fidelity, vertical resolution below 5 nm, and lateral resolution below 100 nm. It is anticipated that such methods suitably can be adapted for use in applying reusable stamps to a medical surface or to a sticker to be applied to a medical surface so as to define a photonic crystal. [0092] For still other exemplary methods of making photonic crystals for which it is anticipated that the method suitably can be adapted for use with the present medical surfaces or stickers for use with the present medical surfaces, see the following references, the following contents of each of which are incorporated by reference herein:

[0093] Gu et al., "Bio-Inspired Vapor-Responsive Colloidal Photonic Crystal Patterns by Inkjet Printing," ACS Nano, Article ASAP, DOI: 10.1021/nn504659p (2014).

[0094] D. R. Huanca, W. J. Salcedo, Porous silicon photonic crystal for refractometer sensor, Iber Sensor, 2008, pp. 312-315.

[0095] Marthelot et al., "Self-Replicating Cracks: A Collaborative Fracture Mode in Thin Films," Physical Review Letters, 113 : 085502, pages 1-5 (2014); for example, controlled reproducible cracking of thin films can be an alternative way to produce an indicator surface. For example, the cracks potentially can act as the air gaps in the periodic arrays and when filled with a fluid result in an visible shift in what the appearance of the surface.

EXAMPLES

[0096] In a first non-limiting example, a photonic crystal was embedded in an outer surface of a commercially purchased, polycarbonate, needle-free connector (MPIOOO-C, CareFusion, San Diego, California) using the following protocol.

[0097] A porous silicon template was obtained that included a photonic crystal with thickness of 30-70 microns, pore size of 5-50 nm, wall thickness of lOnm, porosity of about 35- 70%, using methods such as described in U.S. Patent No. 7,713,778 to Li, U.S. Patent No.

8,206,780 to Li, Benecke, and Sailor.

[0098] The porous silicon (PSi) template was heated to a temperature in the range of 200 °C to 300 °C. More specifically, the porous silicon template was heated to 200 °C, and the male Luer-lok tip of the needle free connector was placed in contact with the PSi template for approximately 20 seconds, until the polycarbonate was observed to melt and to mold into the pores of the template. There was no weight or pressure applied, although weight or pressure optionally can be applied. After approximately 20 seconds, the PSi and needle-free connector were removed from the hot plate and allowed to cool. Upon cooling, the needle-free connector was removed from the PSi template together with the section of PSi template that it was in contact with.

[0099] FIGS. 5A-5E are photographic images of an exemplary medical surface indicating sterilization or disinfection, according to one non-limiting embodiment of the present invention. More specifically, FIGS. 5A-5E are photographic images of the needle-free connector produced using the above-described protocol at different stages of disinfection or sterilization. For example, FIG. 5A is a photographic image of the needle-free connector approximately 5 seconds to sterilization. It may be seen in FIG. 5 A that the tip of the needle-free connector appeared green, which can be interpreted as indicating that a photonic crystal that Bragg diffracts green light was formed by the foregoing steps.

[00100] The needle-connector tip then was swabbed with a 40% isopropyl alcohol wipe, as shown in FIG. 5B. FIG. 5C is a photographic image of the needle-free connector approximately three seconds after it was swabbed with the wipe. As can be seen in FIG. 5C, the tip of the needle-free connector then appeared to be dark red, which can be interpreted as indicating that the liquid from the wipe flowed into the photonic crystal and changed the refractive index of the gaps within the photonic crystal. FIG. 5D is a photographic image of the needle-free connector approximately five seconds after it was swabbed with the wipe. As can be seen in FIG. 5D, the tip of the needle-free connector then appeared to be primarily orange, which can be interpreted as indicating that some of the liquid evaporated relatively quickly from the tip (e.g., from the upper surface of the photonic crystal). As the liquid evaporated, the tip was observed to gradually change back to green. For example, FIG. 5E is a photographic image of the needle-free connector approximately one minute and fifty seconds after it was swabbed with the wipe. As can be seen in FIG. 5E, the tip of the needle free connector appeared to be partially green and partially orange, which can be interpreted as indicating that an additional amount of the liquid had evaporated from the tip (e.g., from relatively deep within gaps within the photonic crystal at the tip).

[00101] In a second non-limiting example, it is anticipated that a photonic crystal can be embedded in an outer surface of a commercially purchased, polycarbonate, needle-free connector (MP1000-C, CareFusion, San Diego, California), or any other polymer surface using the following protocol.

[00102] A porous silicon template is obtained that includes a photonic crystal. Illustratively, the template can be obtained as described above for the first example. Exemplary gap sizes and periodicities are provided elsewhere herein.

[00103] The porous silicon template can be heated to a temperature in a suitable range to melt the polymer surface, e.g., in the range of 200 °C to 300 °C for a polycarbonate surface. The polymer surface, e.g., a male or female Luer-lok tip of a needle-free connector, can be pressed onto the heated porous silicon template until the polymer, e.g., polycarbonate, is observed to melt and to mold into the pores of the template.

[00104] Other techniques suitably can be used to mold a polymer to a PSi template. As one example, a polymer can be injection molded against the PSi template. For this process, a mold can be produced that allows the liquid polymer to come into contact with the PSi template. The resulting molded part could be a complete part or part of an assembly. Part or all of the PSi template optionally can be etched away from the surface. Alternatively, part or all of the PSi can be left on the piece, e.g., as described above in the first example.

[00105] In another technique, the polymer can be softened without melting it by bringing it into contact with a heated PSi template. The parameters can vary based on the polymer and the PSi. Illustratively, the production parameters can correspond to the particular combination of polymer and PSi template. For example, for techniques based on injection molding, production parameters can be selected based on the material(s), the grade of material(s), the size of the mold, and the size of the part that is being molded. The parameters can vary based on the pore size and periodicity in the PSi template. Exemplary parameters for injection molding include, but are not limited to:

[00106] Temperature: Molding temps range from -360 F (e.g., for materials like Santoprene or polypropylene) up to 700 F (e.g., for materials such as LCP or PEEK). Other temperatures suitably can be selected based on the particular material (e.g., polymer) being molded). [00107] Pressure: There are two stages to the injection molding process. The first stage injects the material into the mold and typically uses pressures from 500-1800 psi. The second stage is the holding stage and the pressure range is typically around 300-1200 psi. Other pressures suitably can be used for the first and second stages.

[00108] Time: Cycle time can be selected based on the material and part design, e.g., can be anywhere from 10 seconds up to 3 minutes, or any other suitable period of time.

[00109] Speed: The speed at which the mold is filled suitably can be selected, and can be measured as a percentage and, illustratively, ranges from 5% - 95%.

[00110] In embodiments where pressure is applied, the pressure can be removed and the piece can be allowed to cool to room temperature.

[00111] Optionally, the porous silicon template then can be dissolved from the polymer surface using methods such as described in U.S. Patent No. 8,206,780 and U.S. Patent No.

7,713,778. For example, the porous silicon template can be selectively chemically dissolved. As one example, the template can be selectively removed by oxidative dissolution using a basic solution, e.g., aqueous KOH or NaOH (e.g., 1M), tetramethylammonium hydroxide, or an aqueous solution of ethylene diamine and pyrocatechol.

[00112] The resulting photonic crystal embedded within the polymer surface, e.g., at the tip of the needle-free connector, can Bragg diffract a first wavelength based upon the refractive index of the polymer surface, the refractive index of air, and the periodicity of the photonic crystal.

[00113] A sterilizing or disinfecting liquid can be applied to the polymer surface. For example, the polymer surface, e.g., needle-connector tip, then can be swabbed with a 40% isopropyl alcohol wipe. The appearance of the polymer surface, e.g., the tip of the needle-free connector, can be anticipated to change (e.g., to diffract a second wavelength distinguishable from the first wavelength) so as to indicate that the sterilizing or disinfecting liquid flows into the photonic crystal and changes the refractive index of the gaps within the photonic crystal. As the liquid is removed, e.g., evaporated, the surface can be anticipated to again Bragg diffract the first wavelength. [00114] In a third non-limiting example, it is anticipated that a photonic crystal can be embedded in a polymer surface using the following protocol.

[00115] A porous silicon template is obtained that includes a photonic crystal, e.g., as described elsewhere herein.

[00116] The porous silicon template can be heated to a temperature in a suitable range to melt the polymer, e.g., in the range of 200 °C to 300 °C for polycarbonate. The polymer is heated to a temperature in a suitable range to melt the polymer, e.g., in the range of 200 °C to 300 °C for po carbonate' and then is poured onto the heated porous silicon template and a suitable pressure applied, e.g., using a metal shim.

[00117] The piece can be allowed to cool to room temperature.

[00118] Optionally, the porous silicon template then can be dissolved from the polymer surface using methods such as described in U.S. Patent No. 8,206,780 and U.S. Patent No.

[00119] The resulting photonic crystal embedded within the polymer surface can Bragg diffract a first wavelength based upon the refractive index of the polymer surface, the refractive index of air, and the periodicity of the photonic crystal.

[00120] A sterilizing or disinfecting liquid can be applied to the polymer surface. For example, the polymer surface then can be swabbed with a 40% isopropyl alcohol wipe. The appearance of the polymer surface can be anticipated to change (e.g., to diffract a second wavelength distinguishable from the first wavelength) so as to indicate that the liquid flows into the photonic crystal and changes the refractive index of the gaps within the photonic crystal. As the liquid is removed, e.g., evaporated, the surface can be anticipated to again Bragg diffract the first wavelength. Alternative Embodiments

[00121] While various illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the invention. The appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of the invention.

Claims

WHAT IS CLAIMED:

1. A method for sterilizing or disinfecting a medical surface, the method comprising:

providing a medical surface comprising a photonic crystal;

responsive to exposure to air in the absence of a sterilizing or disinfecting liquid, Bragg diffracting light of a first wavelength by the photonic crystal;

applying the sterilizing or disinfecting liquid to the photonic crystal;

responsive to applying the sterilizing or disinfecting liquid, Bragg diffracting light of a second wavelength by the photonic crystal, the first wavelength being distinguishable from the second wavelength;

based on the Bragg diffraction of the light of the second wavelength, determining that the medical surface is respectively sterilized or disinfected by the sterilizing or disinfecting liquid.

2. The method of claim 1, further comprising:

removing the sterilizing or disinfecting liquid from the photonic crystal; and

responsive to the removing of the sterilizing or disinfecting liquid, again Bragg diffracting light of the first wavelength by the photonic crystal.

3. The method of claim 2, further comprising, based on the Bragg diffraction of light of the first wavelength again, determining that the medical surface is ready for use.

4. The method of claim 1, wherein the photonic crystal is embedded within the medical surface.

5. The method of claim 1, wherein the photonic crystal is adhered to the medical surface.

6. The method of claim 1, wherein the photonic crystal is self-assembled onto the medical surface.

7. The method of claim 1, wherein the photonic crystal is painted onto the medical surface.

8. The method of claim 1, wherein the photonic crystal is welded to the medical surface.

9. The method of claim 1, wherein the medical surface comprises a first polymer, and wherein the photonic crystal comprises a second polymer.

10. The method of claim 9, wherein the first polymer is different than the second polymer.

11. The method of claim 1, wherein a surface of the photonic crystal is functionalized to enhance wetting of the photonic crystal by the sterilizing or disinfecting liquid.

12. The method of claim 10, wherein the functionalization enhances wetting of the photonic crystal by the sterilizing or disinfecting liquid selectively relative to at least one other liquid.

13. The method of claim 1, wherein the medical surface defines at least a portion of a medical device.

14. The method of claim 13, wherein the medical device includes an intravascular device.

15. The method of claim 13, wherein the medical device includes a connector.

16. The method of claim 1, wherein the medical surface defines at least a portion of a tray.

17. The method of claim 1, wherein the medical surface defines at least a portion of a medical drape.

18. The method of claim 1, wherein the medical surface defines at least a portion of a floor, wall, counter, or door of a health care facility.

19. The method of claim 1, wherein the sterilizing or disinfecting liquid comprises ethanol.

20. The method of claim 1, wherein the photonic crystal comprises an opal.

21. The method of claim 1, wherein the photonic crystal comprises a substantially periodic array of pillars surrounded by air.

22. The method of claim 1, wherein the first and second wavelengths are visible to the human eye.

23. A medical surface comprising:

a photonic crystal disposed on or embedded within the medical surface,

the photonic crystal Bragg diffracting light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid,

the photonic crystal Bragg diffracting light of a second wavelength responsive to applying the sterilizing or disinfecting liquid, the first wavelength being distinguishable from the second wavelength,

the medical surface being respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid.

24. A sticker comprising:

a photonic crystal disposed on or embedded within a surface of a polymer,

the sticker being respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid; and

an adhesive disposed on the polymer, the adhesive configured to adhere the polymer to an article.

25. A wall, floor, counter, or door comprising:

a photonic crystal disposed on or embedded within the wall, floor, counter, or door, the photonic crystal Bragg diffracting light of a first wavelength responsive to exposure to air in the absence of a sterilizing or disinfecting liquid,

the wall, floor, counter, or door being respectively sterilized or disinfected responsive to the applying of the sterilizing or disinfecting liquid.