WO2014063843A1

WO2014063843A1 - Sensor element with a photonic crystal arrangement

Info

Publication number: WO2014063843A1
Application number: PCT/EP2013/064822
Authority: WO
Inventors: Matthias Stich; Sabine Trupp; Anna HEZINGER; Jennifer Schmidt; Gerhard Mohr
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2012-10-26
Filing date: 2013-07-12
Publication date: 2014-05-01

Abstract

A surgical stocking has a stocking material and a sensor element mounted on or in the stocking material. The sensor element has a measurement area (a measurement surface) and a photonic crystal arrangement with an optical property, wherein the optical property of the photonic crystal arrangement can be changed by the action of a physical measured variable on the photonic crystal arrangement within the measurement area, and therefore the change in the optical property can be detected if it occurs when acted on by the physical measured variable.

Description

Sensor element with a photonic crystal arrangement

description

Embodiments of the present invention relate to a sensor element having a photonic crystal arrangement for sensing an analyte, a sensor element having a photonic crystal arrangement for sensing a physical eigenshaft, and the use of a photonic crystal arrangement as a sensor element. Further exemplary embodiments relate to a method for producing and setting a sensor element and to a system having such a sensor element. Preferred embodiments relate to compression stockings or medical thrombosis prophylaxis stockings.

In many everyday and scientific applications, simple sensor elements, e.g. in the form of a measuring strip, for use. Examples include pH measuring strips, blood glucose measuring strips or strain gauge strips. A sensor element of a pH measurement strip has, for example, dyes which discolor depending on the pH, so that the measurement result can be read optically directly. Another group of these knife strips, which also includes some blood glucose measuring strips or strain gauge strips, refers to sensor elements that can only be evaluated with a separate sensor system. Such sensors are in contradiction to the concept of measuring strips, which is based on simple handling, cost-effective production and specific adaptation to the measuring task.

Object of the present invention is therefore to provide a sensor element, which on the one hand is inexpensive to manufacture and easy to use, has high accuracy and is very well matched to the respective sensor applications and the particular application with special focus on medical applications.

The object is achieved by a medical stocking according to claim 1, a medical bandage according to claim 13 and 15, a sensor element according to claim 29, 30 and 31 and by a method for manufacturing according to claims 25 and 26.

Embodiments of the present invention provide a sensor element having a photonic crystal arrangement and a plurality of receptor sites integrated into the photonic crystal array. The photonic crystal arrangement has due to their Structure one or more optical properties. The receptor sites are designed for the selective interaction with analytes, wherein the optical property, eg coloration, absorption, reflection or fluorescence, of the photonic crystal arrangement based on the analytes attached to the receptor sites and / or based on direct chemical and / or or physical interaction of the analytes with the receptor site are changeable. Thus, therefore, sensor elements or generally an optical sensor without chromophoric systems in the true sense, ie without dyes and pigments created. Sensor elements based on photonic crystals represent a completely new kind of optical sensors.

Further embodiments provide a sensor element with a measuring range and a photonic crystal arrangement, which has optical properties. The optical properties are within the measurement range by the action of a physical measurand, such as a laser beam. a temperature, a current, a charge or a magnetic field strength, changeable.

Embodiments of the present invention are based on the recognition that a photonic crystal arrangement, which is formed for example from an array of particles, by certain process steps, such as by the choice of the starting particles, introduction of receptor sites or by introducing defects on a respective Measurement application can be adjusted. In this case, in particular the reaction to a measured variable, for example to a concentration of analytes or to a mechanical force acting on the photonic crystal arrangement, is set. The evaluation of a measurement with such a sensor element takes place optically on the basis of the optical property which arises as a result of the measured variable, that is to say for example based on the coloring. In this case, the optical properties of the photonic crystal arrangement are formed, in particular, via the different (alternating) refractive indices present in the optical crystal arrangement, these changing as a result of the measured variable to be measured. The alternating refractive indices are formed by arranging particles with a first refractive index next to one another, while the intermediate heights arising in the arrangement due to the geometry of the particles have a second, different refractive index (η ^ η). The change of the optical property or of the respective refractive index results, for example, in a color change or another optical reaction, which is preferably readable by the human eye, that is to say lies in the visible range. Fields of application of such sensor elements are manifold and extend from chemical or biological test strips via complex chemical or biological detectors to strain gauges or also sensors for physical measured variables. According to further Ausführangsbeispielen so the optical properties of the photonic crystal arrangement on the introduced particles, on the introduced defects or by means of an envelope or Polymcrumhüllung be adjusted so that the measuring range is adapted to the measured variable to be detected and / or the desired optical properties. Conversely, this means that an adaptation to the respective sensor application is possible via the said mechanisms.

According to embodiments, the above-mentioned receptor sites are designed to allow analytes to couple selectively based on a protein-protein interaction. By occupying the receptor sites with analytes, the optical properties of the photonic crystal arrangement are influenced. Furthermore, the optical properties can also be changed by a direct, either chemical or physical, interaction between analytes and certain regions of the photonic crystal arrangement, which are also referred to as receptor sites. By means of such interactions, it is advantageously possible to detect previously not detectable analytes.

According to further embodiments, the photonic crystal arrangement may be formed on a rigid or flexible substrate, such as a substrate. a glass substrate or polymer substrate or textile substrate are applied. As a result, for example, applications such as a medical bandage with a sensor element mentioned above can be realized, e.g. by means of its color indicates whether it is too tight or if there are impurities. Furthermore, strain gauges can be realized, which react to a tensile force, for example, with a change in color.

According to a further embodiment, the present invention provides a manufacturing method of the above-mentioned sensor element, according to which particle defined refractive index, defined size and / or shape are arranged to a photonic crystal arrangement and according to which the receptor sites are introduced and / or the measuring range is set.

Another method relates to the adjustment of the measurement functionality of the sensor element comprising the step of introducing the defects and / or the particles defined refractive index, size and / or shape to at least two alternating or multiple refractive indices within the optical properties photonic crystal arrangement adapt. This method advantageously enables the use of a photonic crystal arrangement as a sensor element Adaptation of the same to the respective measurement application and in particular the coordination between the measurand and the optical response.

The above-described sensors or strain gauges based on photonic crystals can be used, for example, in medical compression stockings or medical thrombosis prophylaxis stockings. Further embodiments provide a medical stocking with a medical stocking material and a sensor element attached to the medical stocking material, wherein the sensor element has a (area) measurement area (or a measurement area), and a photonic crystal arrangement with an optical property, wherein the optical property the photonic crystal arrangement can be changed within the measuring range by the action of a physical measured quantity on the photonic crystal arrangement, so that the change in the optical property can be detected if the change in the optical property occurs when the physical measured variable acts.

In the following, further findings and inventive conclusions of the inventors are also made taking into account the object underlying the present invention. The inventors have recognized that a sensor element having a photonic crystal arrangement is possible for detecting and quantifying certain physical quantities and parameters, i. planar optical sensors can be realized. Thus, it is possible in particular to realize a system for displaying expansion, tensile or shear forces with the aid of color changes or changes in fluorescence. For example, such a system may be referred to as an optical strain gauge.

The need for such gauges is very high, especially for everyday applications. An important example is the control of the fit of medical compression stockings or medical thrombosis prophylaxis stockings (V1TPS). These stockings can fully unfold their correct medical effect only in ideal fit. If they are too loose, the effect is lost. However, if they are too tight, negative effects for the patient can occur. So far there is no method or procedure to display the fit quickly and reliably. However, it is extremely important, especially for untrained personnel and individuals, to determine the correct size and ideal fit of stockings. These are an object of everyday use, so it is of great relevance to grasp the Anpressdruek these knits at defined positions on the leg. Since the application of these stockings is often performed by laymen, the result of the measurement should be best in the form of an optical Signals provide information about the correct stocking size and the associated medically correct pressure of the knit on the leg.

Thus, systems for surface optical detection of strain forces can be realized. The application to medical compression stockings and / or medical thrombosis prophylaxis stockings is thus possible.

Embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. 1 shows an exemplary representation of a sensor element with a photonic crystal arrangement and integrated receptor sites for the selective interaction with analytes according to an exemplary embodiment; a schematic representation of a sensor element with a photonic crystal arrangement and a measuring range for the detection of a physical measured variable according to another embodiment; an exemplary representation of a Thromboseprophylaxestrumpfes with an incorporated sensor element according to a preferred embodiment; a schematic diagram illustrating the method of manufacturing the sensor element of Figures 1 and 2 and the method for adjusting the measurement functionality of the sensor element according to embodiments. and a chemical (colloidal) production process of photonic crystals, such as those used in the embodiment of FIG. 3, and their application as strain gauges according to another embodiment.

It should be noted that identical or equivalent elements are provided with the same reference numerals, so that the description of which is interchangeable or can be applied to each other. Before embodiments of the present invention will be explained in more detail beforehand with reference to the accompanying figures, photonic crystals and the knowledge associated with these, which have led to this invention, will be discussed in general. Under photonic crystals are understood in principle periodic structures of different refractive indices. These influence the refraction, scattering, reflection and / or interference of light (eg visible light, infrared light) which transilluminates or traverses the photonic crystal. In this way, there is the transmission or remission of colored light, although in the system no dye, pigment or the like is present. The color of the transmitted or reflected light may be controlled by the nature and arrangement of the periodic structures in the photonic crystal array. Photonic crystal arrangements, which are typically in a solid state of aggregation, are different from interference and diffraction gratings in that they are both one-dimensional (see photonic crystal fiber), two-dimensional and three-dimensional (see reverse opals, reverse side opal) can. The optical properties of the photonic crystal arrangements can be influenced or adjusted during the manufacturing process, for example.

There are different methods on the basis of which photonic crystal arrangements can be produced with different starting materials. One possibility is to introduce fine holes of defined size into an optically transparent material by means of drilling. Further manufacturing processes originate from semiconductor technology (eg lithography, nanoimprinting or hot embossing printing) and include, for example, steps such as structuring by means of mask technologies or etching. Another production method is based on the direct formation of the crystal structure. Here, organic or inorganic nanoparticles and / or microparticles are directly arranged and / or immobilized, so that the photonic crystal arrangement is formed. As such, photonic crystal assembly fabrication techniques have become more diversified and simpler in recent years, allowing for cost considerations to use such photonic crystal arrays for non-reusable applications, such as sensor elements, as the hurdle of adapting the photonic crystal array to the respective ones Sensor application can be taken. 1 shows a sensor element 10 with a photonic crystal arrangement 12 which has a multiplicity of particles 12a to 12f arranged in accordance with a crystal structure. The particles 12a to 12f may, for example, have a sphere tonn and metals, polymers, minerals, crystals, natural products, fabric, paper, textile, glass, crystalline and / or amorphous substances. Due to their shape, the arrangement of the particles 12a to 12f in the crystal arrangement 12 is designed such that intermediate spaces filled with air, for example, are formed between them. With such an arrangement of the particles 12a to 12f with a first refractive index ni together with the intermediate spaces which have a second refractive index n ₂ (or nmi _t ), the refractive indices ni and n ₂ alternate periodically, which leads to a one, two or three dimensional grid structure is formed. Thus, the particles 12a to 12f together with the gaps define the optical properties of the photonic crystal array 12 on the one hand on the respective refractive indices nj / n ₂ and on the other hand on the spatial extent of the particles 12a to 12f and gaps that influence the lattice constant of the photonic crystal array 12th Has.

The repetition of the different refractive indices ni and n ₂ and the dimension of the particles 12a to 12f or interspaces (see period length) determine the wavelength range of the electromagnetic radiation to which the crystals interact to an increased degree, since the alternating refractive indices ni and n ₂ the photonic crystals interact with electromagnetic waves in a manner similar to the periodic potentials in semiconductor crystals with electrons. As a result of the wavelength dependence, photonic band structures can arise that have "forbidden" energies, so that electromagnetic waves of specific wavelengths can not propagate or be filtered within the crystal arrangement 12. Consequently, the colors become reflection or transmission via these mechanisms In addition to the regions 12a to 12f or the intermediate regions of different refractive indices n / n ₂ and different expansion, the relative permeability or dielectric constant ε of the photonic lattice arrangement 12 also contributes to determining the optical properties This means that the optical properties (color, fluorescence, phosphorescence, chemiluminescence, luminescence or luminescence intensity or transmission, reflection scattering, emission) by the nature and condition of the materials used or by the arrangement of the crystal structure, ie caused by the (highly) ordered periodic arrangement of regions of different refractive indices nj and n ₂ , and do not depend on the chemistry of dyes.

Receptor sites 14 are integrated in the crystal arrangement 12, wherein these can be arranged, for example, between the particles 1 2d to 1 2f or can be deposited on or incorporated in the particles 12d to 12f. The receptor sites 14 are designed to selectively interact with an analyte 16 (eg, liquids, gases, ions, metabolites, natural products, biomolecules, proteins, bacteria, viruses, RNA and / or DNA). There- For example, the receptor site 14 may be a receptor molecule. Ligands, complexing agents, indicators, nanoparticles or microparticles (eg inorganic, organic, polymer particles, metallic micro- or nanoparticles of silver, gold, cobalt etc., quantum dots, semiconductors, upconverting particles, inorganic or organic pigments, core Sheath systems of organic and / or inorganic components), each of these receptor types 14 interacting with different analytes 16.

The receptor sites 14 are designed in such a way that, on contact with a substance 16 to be detected, the refractive index ni of the respective particles 12a to 12f and / or the dimension thereof and thus the lattice constant changes, which results in an analyte-dependent change in the optical property (eg absorption, Change in color, fluorescence or phosphorescence) results. Alternatively, the receptor sites 14 may be configured such that upon an addition of an analyte 16, a change in the refractive index n ₂ and / or the dimension of the interstices occurs. Regardless of the exact mechanism of action, the medium in which the light propagates changes so that the light refracts differently upon the presence or accumulation of the analyte 16, for example, as if the light in a region of equal refractive index is a further distance would go through. According to one embodiment, in the presence of the analyte 16, such as an amine, the optical properties may change as the previously approximately equal refractive indices nj and n ₂ shift (ie, for example, none ₎ due to the analyte interaction Change of the refractive index n _1, but magnification of the refractive index n ₂ ), so that frequency ranges of the light are selectively transmitted or reflected by the crystal arrangement 12 (see filter). As a result, for example, the coloration of the sensor element 10 changes. Thus, with these very simple sensor elements 10 analytes 16 can be detected and quantified. Application examples here are the detection of borderline relevant analytes, in which case the sensor element reacts, for example, with a color change (eg green to red when exceeding the respective limit value or in the presence of certain analytes or parameters).

An example of detection of amines is the trifluoroacetyl group-amine interaction. Receptors 14, which cause a visible change in the control surface for reactive oxygen species, can be, for example, redox systems, frequently using metal-ligand complexes and the recognition reaction then taking place at the metal center. Metal-ligand complexes are also used for the fluorescent detection of oxygen. Fluorescein sulfonate groups are selective receptor groups for hydrogen peroxide, maleic imide are selective receptor groups for thiols, tricyanovinyl groups are selective receptor groups for primary and secondary amines, pyry1-functional are selective receptor groups for primary amines, hydrazine functions are selective receptor groups for aldehydes and etone, amino groups are selective receptor groups for aldehydes and ketones. Boronic acid functions are selective receptor groups for diols, 1, 2-diaminobenzene groups are selective receptor groups for nitrogen oxides, aldehyde functions are selective receptor groups for amino acids. In addition, other recognition mechanisms such as antigen-antibody interactions, DNA-DNA or DNA-RNA interactions, antibody-protein interactions, enzyme-substrate interactions as well as recognition mechanisms via molecularly imprinted polymers (MIP, molecular imprinted polymers) in the photonic crystal can be implemented.

As already mentioned above, a direct interaction can also be a change in the optical property of the photonic crystal arrangement 12, as will be explained below with reference to a further exemplary embodiment. This results in a direct interaction between the analyte 16 and a region of the photonic crystal arrangement 12, which is referred to as receptor site 14. The photonic crystals can be designed to change their properties upon contact with certain substances. For example, the polymer particles present in the crystal may swell in the presence of certain solvents. In doing so, they change their volume (and thus their size and density) which, as explained above, can cause a change in their color due to the change of the lattice constant. It does not matter whether the substance to be detected is liquid or gaseous. Such systems can be used eg for monitoring the water quality (detection of small amounts of organic solvents in groundwater) or for quality assurance of fuels (detection of water in organic liquids such as gasoline). Further examples of such direct-acting interactions are the so-called dipole-dipole interaction or else the magnetic interaction which, for example, results in a change in the crystal structure due to the presence of a magnetic field in certain particles 12a to 12f. In this context, the so-called quenching interaction is mentioned, in which certain substances (so-called quenchers) quench the fluorescence or phosphorescence of dyes. With these two forms of receptor sites 14, both gaseous and liquid analytes 16, such as, for example, oxygen, reactive oxygen species (including hydrogen peroxide and ozone), CO, SO, SO. CO, acids, alkalis, amines, carboxylic acids, aldehydes, ketones, ions in general, saccharides, alcohols, diols, thiols, nitrogen oxides, Proteins, metabolites, aromatics, heterocycles, organophosphorus compounds and amino acids. The interaction with the (modified) photonic crystal arrangement 12 can be reversible (sensor for continuous measurements) as well as irreversible.

The sensor element 10 may have an optional substrate 19 according to further embodiments. This optional substrate 19 can be, for example, a rigid substrate, in the form of a metal substrate, glass substrate or polymer substrate, or else realized as a flexible substrate in the form of a textile substrate, polymer substrate or paper substrate.

FIG. 2 shows another sensor element 10 'with a photonic crystal arrangement 12, which likewise has a plurality of particles 12a to 12f and intermediate spaces formed therebetween with different refractive indices ni and n ₂ . Furthermore, the sensor element 10 'has a defined measuring range. Within this measurement range, the photonic crystal array 12 of the sensor element 10 'or at least a portion of the photonic crystal array 12 responds to a physical measurement such as temperature, current, external force (gravity, tensile force under pressure) or magnetic field by means of a change the optical properties. In this measuring range (eg from 0 - 500 ° C, 50 - 2000 mbar or 3 - 800 ppm) a change of the optical property is made so that it can not only be detected but also quantified. For this purpose, therefore, a specific optical property (eg a respective hue) is assigned to a respective measured value. The underlying principle basically corresponds to the principle described in FIG. 1, wherein here the changes in the optical property are based on the fact that a (mechanical) displacement of the lattice structure takes place as a result of an external influence acting on the crystal arrangement 12. This shift, for example, alters the spatial extent or dimension of the particles 12a to 12f and / or the interspaces. The external influence can be supplied, for example, directly by an external force (with a one-dimensional or multi-dimensional force) or by a force acting by means of a magnetic field or also by the brown M o 1 ek u 1 a rbe w at at an acting temperature. Furthermore, an electric current, which also results in a change in the macromolecular structure, is a possible cause for a change in the lattice structure 12, so that it can consequently also be optically detected. Analogous to the above example from FIG. 1, a previous adjustment of the optical property and in particular of the measuring range by means of a stellmeehanismen. which are explained in detail with respect to FIG. 4. In the following, two exemplary examples for the measurement of physical quantities are discussed.

In the first example, the detection of a magnetic field acting on the sensor element 10 'or, to be precise, a magnetic flux as a measured variable is assumed. This magnetic flux acts on the crystal assembly 12 such that a change in optical property, e.g. in the form of self-adjusting reflection, is observable. For example, in the particles 12a to 12f, which are magnetic (or generally designed to react to a magnetic field), a magnetic flux causes a change in the grating structure. Specifically, for example, the presence of a magnetic field with a field strength of 1 Weber [Wb] can result in an increase of the refractive index by 10% ni or in a reduction of the lattice constant by 10%, so that the refraction characteristic changes depending on the wavelength. As a result, in the case of the sensor element 10 ', the wavelength range of the refraction occurring can shift so that they now lie in the visible range (under the action of the magnetic field).

The detection of a further measured variable carried out by way of example below will be explained with reference to a specific application. In this application are textiles which are provided by means of the above-described sensor element 10 'with a measuring functionality. The photonic crystal 12, which reacts due to a mechanical stress (displacement of the lattice structure) with a change in the optical properties, is in this case integrated into the textile fabric forming the optional substrate 19. In this case, it is possible to immobilize the crystals of the crystal assembly 12 in or on the fabric 19 (or yarn), or to produce the crystals themselves as a thin thread. In this way, the material (compare particles 12a to 12f) can be introduced into various textile products, whereby, for example, dressing materials, thrombosis stockings or the like with sensory properties can be produced. These textiles are then able to indicate too tight a fit or too tight winding of the fabric by a color change or generally by a change in the optical property. Especially with wound dressings the perfect fit is of great importance for the healing of the patient. Through associations with photonic crystals as a sensory unit could be immediately recognized by anyone by the color, whether the dressing was applied too loose or too tight. In this case, it is not absolutely necessary for the entire textile to be provided with photonic crystals. It is sufficient to provide certain areas with the sensory function (eg a woven thread or an incorporated sensory "patch"). FIG. 3 shows a thrombosis stocking or compression stocking 100 with a measurement functionality, as described in FIGS. 1 and 2. For this purpose, the thrombosis stocking 100 has, for example, a flexible stocking material 102, such as, for example, an elastane. which is entangled in a fabric. Here, the structure and the material is such that a support function can be realized. To realize the measurement functionality thrombosis stocking further comprises a sensor element 104, which basically corresponds to the sensor elements 10, 10 '. The sensor element 104 may, for example, comprise its own flexible substrate (not shown) and be sewn or glued onto the sock material 102. In other words, this means that such a measuring strip 104 is applied, for example, to the surface of the compression stocking 100 in the form of a sticker, a sewn-on strip or similar systems. According to further embodiments, it would also be possible for the fabric of the stocking material 102 to at least partially comprise a yarn in which the sensor element 104 or the photonic crystal is directly integrated. In this respect, therefore, the sensor element 104 may be woven into the sock material 102.

Analogous to the above explanations, the sensor element 104 has the photonic crystal arrangement which has predetermined optical properties (eg coloring), wherein the optical properties can be changed by the action of a physical measurand, such as a mechanical stress (eg color change). In other words, this means that an optical strain gauge is integrated into medical compression stockings or medical thrombosis prophylaxis stockings (MTPS) and in particular serves to control and monitor the correct fit of the same. The background to this is that, as described above, the photonic crystals can be used as a sensory system for detecting and quantifying tensile forces when the photonic crystal arrangement is immobilized in an elastic material (polymer, fiber, tissue or the like) is. It does not matter whether it is micro- or nanoparticles of any kind or defined defects (holes) in the material. By applying a mechanical stress such as compressive, shear or tensile forces, the distances between the particles or holes and, where appropriate, their spatial extent / orientation change. As a result, the regions or dimensions of different refractive indices also change, which leads to changes in the optical properties of the material (compare process D in FIG. If, for example, one wants to detect the applied expansion forces, one can set the measuring range by selecting the particle size and elasticity of the matrix material, or determine the force at which the system has a color change. The force to be applied to the color change can be adjusted by the size or the material of the particles / holes used or by the elasticity of the fixing material. The test strip may be sutured, entangled, glued, ironed or applied to the surface of the sock by any other conceivable method. It is also possible. To provide threads or yarns with a photonic crystal arrangement, which are then implemented directly in the manufacturing process of the fabric / knit fabric, so that the fabric / knit intrinsically has functionalities (display unit or control unit) of the optical strain measurement. In summary, this means that such stretch test strips are integrated into the textiles described above (but also other textiles) as a control element in order to measure the contact pressure at defined points of the leg. The result of this measurement can be done optically via one or more color changes. The correct fit of the stockings can thus be visualized by indicating too low and too high pressure of the textiles on the leg due to different colors of the strain gauge.

In general, for such applications 100, all of the described optical sensor systems or test strips 104, 10, 10 '(which do not contain any (luminescent) dyes, indicators, pigments or the like (except systems based on liquid crystals) may be used, so according to further embodiments In addition, sensor elements which react to the presence of analytes may also be integrated into the stocking 100.

A possible production of the crystal arrangements 12 for the sensor elements 10 and 10 'shown in FIGS. 1 and 2 will be explained below with reference to FIG. 4, with particular attention being paid to the setting of the optical properties and the measuring range.

FIG. 4 shows in a representation (a) the production and the adaptation steps carried out during production. In this case, micro- and / or nanoparticles 12x are arranged in a step A such that the photonic lattice arrangement 12, which has at least a first refractive index ni, arises. The particles 12x have a defined size or a defined diameter, from which, for a given refractive index ni of the material, the wavelength of the electromagnetic wave is dependent, in which an interaction between the photonic crystal arrangement 12 and the electrochemical magnetic wave is formed. In this step A, the modified particles 12x are brought into a highly ordered structure, such as in the form of a hexagonal closest packing (three-dimensional case). By arranging arise between the particles 12x cavities, which are filled for example with a gas such as air, and thus has a refractive index n ₂ (= n _air ). The crystal arrangement 12 produced by means of this step A is already in this state an optically active material, ie, it is designed to interact with electromagnetic waves, since regions of different refractive indices nj and n ₂ , here n _air , repeat periodically. In this chemical preparation (step A), for example, inorganic, organic, metallic or polymeric particles (eg silica, polystyrene, polyvinyl chloride, cobalt, silver or gold particles and inorganic and / or organic pigments, "upconverting" nanoparticles, It should also be pointed out that a chemical connection by means of so-called core-sheath systems made of organic and / or inorganic components is also possible.This photonic crystal arrangement produced in this way can either be used directly for the respective measuring task (FIG. 1) or detection of a physical measured variable from FIG. 2) (see step D) or first be changed so that the optical properties are matched to the respective measuring functionality, which will be explained in more detail below.

Step B shows the sheathing of the photonic crystal arrangement 12 with a transparent shell 22, for example a polymer shell, which has a further refractive index n ₃ , whereby the optical properties of the sensor element to be adjusted are changed. The end product of the production step B thus has altered optical properties compared with the end product of the production step A, since a different material (in comparison to gas or air, namely the cladding 22 with the refractive index n ₃ (= n _po i _yme r φ The photonic lattice arrangement 12 with the cladding 22 can be further modified, for example, by selectively removing the particles 12x used and thus generating periodic voids 24. This selective integration of defects 24 takes place in the production step C. The final product of the production step C in turn has altered optical properties, since the vacancies 24 have a further refractive index n ₄ , which differs from the refractive index ni of the removed particles or in particular a changed ratio between the refractive indices n ₄ to n ₃ in comparison to n ₃ comes to ni The defects 24 are also the chemical, physical and sensory properties of the photonic Crystal arrangement, because the vacancies 24 generated within the sheath 22 typically improve the permeability and the response for (gaseous) analytes. The sensor element 10 or 10 'produced by means of the production steps A and the optional production steps B and / or C can be adapted to the respective measuring task in a further step D, as illustrated in the illustration (b). In this case, starting from the adapted crystal lattice arrangement 12 (that is to say either starting from the end product of the production step A or the end product of the production step B or from the end product of the production step C), the crystal lattice arrangement 12 is modified such that the sensor element 10 for the detection of analytes (FIG. see Fig. 1) or the sensor element 10 'for the detection of a physical measured variable (see Fig. 2) is generated. In step D, therefore, in a first case, the (chemical or physical) receptor sites 14 or recognition units (with other recognition mechanisms) are implemented in the crystal arrangement 12 or in the particles 12x. This can then result in a change in the refractive index ni to m 'of the particles or ru to Ώ4 of the vacancies 24. Furthermore, in step D, the sensory system can also be formed into a direct interaction, for example by selecting or modifying the materials used for the photonic crystal arrangement 12.

The manufacturing step D can be used in a second case to adjust the measuring range. Here, a kind of calibration of the sensor element 10 'takes place, so that respective optical properties (eg a multiplicity of different color shades) of the crystal arrangement 12 correspond to respective physical properties within the measurement range, which extends from a minimum value of the measurement value to be detected up to a maximum value thereof , be assigned. The measuring range can be documented in the form of a scale, which creates an association between an expression of the optical property and the respective measured value.

Even though the arranging or chemical arranging of the particles 12x is assumed in the above-described production methods, the above-described photonic crystal arrangements 12 (cf step A) can also be used with other production methods, such as, for example, with methods from the semiconductor industry or with a production method which is assumed by a solid material and the voids and thus the structure are introduced by means of a fine drill as holes in the solid material produced. Referring to FIG. 1, it should be noted that the particles 12a to 12f need not necessarily have the same material, so that different particles with different (optical) properties may also be arranged in the crystal lattice arrangement 1 2. Thus, the crystal lattice assembly 12 would have more than two different (alternating) refractive indices.

With reference to FIGS. 1 and 2, it should be noted that the sensor element 10 or 10 'may have the optional sheath 22 or polymer sheath, so that the resulting interspaces may be filled with a different material, as in FIG. 4 is explained in more detail. This cladding 22 has a further refractive index n ₃ and thus contributes to the determination of the optical properties of the sensor element 10 or 10 '. Referring to FIGS. 1 and 2, it should be noted that according to further Ausführangss- examples, the photonic crystal lattice assembly 12 may also have defects, so not introduced or selectively removed particles with a further refractive index. These imperfections can be particularly well introduced into the grid assembly 12, if it is fixed with a sheath 22 (see above).

According to further embodiments, the Kri stall arrangement 12 of Fig. 1 and 2 between the particles have gaps which is filled for example with a gas or air and thus has a further refractive index ncas / air. According to a further exemplary embodiment, these intermediate spaces can be filled with a casing 22, for example a polymer casing, as explained in greater detail with reference to FIG. 4. This cladding 22 has a further refractive index n ₃ and thus contributes to the determination of the optical properties of the sensor element 10 or 10 '. In general terms, this means that the crystal arrangement 12 alternatively comprises a multiplicity of repeating units, which are preferably arranged periodically.

According to a further embodiment, a combination of the sensor element 10 and 10 'would be conceivable in which both analyte 16 and a possibly associated with this analyte 16 physical property is detectable. Referring to Fig. 4, this means that in the fabrication step D, the crystal assembly 12 is provided with both the receptor sites 14 and a predefined measurement area. As already shown above, the sensor elements 10 and 10 'produced by means of the photonic crystal arrangement 12 can be used in a variety of ways and are distinguished, in particular, by their simplicity and the associated cost-effective production. In particular, the production steps illustrated in FIG. 4 can be integrated into many already existing production processes, resulting in many fields of application for the sensor elements 10 or 10 'or the probes 10 or 10' produced in this way. Exemplary further processing methods are roll-to-roll processes, screen printing, inkjet printing, spray-dip spincoating, injection molding, lithography, etching, hot stamping, anodizing and nanoimprinting.

Due to this integrability in different production methods or the applicability of the photonic crystal arrangement 12 to different substrates 19, the sensor element 10 or 10 'can be divided into different products, such as e.g. Semiconductor products, electronic components, are integrated. As already explained above, different substrates 19, such as e.g. a glass substrate, tissue substrate, textile substrate or plastic substrate, can be used so that customized sensors or test strips (chemical test strips or strain gauges) can be produced. Therefore, further embodiments of the present invention relate to a test strip with a photonic crystal arrangement, which forms a change in the optical properties depending on an attached analyte or an acting physical quantity.

Another embodiment relates to a measuring system comprising a sensor element 10 or 10 'and a read-out device. The read-out device is designed to detect the optical properties or the change in the optical properties and, in particular, a correlation between the change in the optical property (eg the degree of color change) and the measured variable of the physical parameter to be measured or the concentration (content, Amount and / or strength) of the analyte. By choosing the materials of the photonic crystal arrangement 12, the measuring range, the sensitivity and the range of the color change can be adjusted continuously. In addition, selectivity can be induced via the choice of the recognition unit and the materials used (eg the polymer for fixing) and thus cross sensitivities are minimized. Further embodiments relate to the use of a photonic crystal arrangement 12 as a sensor element. The areas of application extend from science and technology, medicine, biology as well as all everyday and everyday objects, in which optical sensors, test strips, recognition units or the like are used and / or integrated or analytes or physical parameters and parameters are displayed and / or quantified.

A possible production of the crystal arrangements 12 shown in FIGS. 1 and 2 for the sensor elements 10 and 10 'or, in particular, of the medical stocking shown in FIG. 3 is explained below, with particular reference to the setting of the optical system Characteristics and the measuring range. 5, the production and functionality of a sensor element 10 with a photonic crystal arrangement 12, which has a multiplicity of particles 12a to 12f arranged corresponding to a crystal structure, is illustrated, wherein this sensor element 10 is represented, for example, as an "optical strain gauge". It should be noted that the above statements regarding FIGS. 1-4 are equally applicable to the following explanations and exemplary embodiments.

The optical strain gauge consists of colloidal photonic crystals immobilized in a suitable material. Due to their structure, photonic crystals have exceptional and remarkable optical properties. Due to the highly ordered periodic arrangement of regions of lower and higher refractive indices (or relative permittivity or dielectric constant ε), photonic crystals interact with electromagnetic waves in a manner similar to the periodic potentials in semiconductor crystals with electrons. The period length and the repetitions of the different refractive indices determine the wavelength range of the electromagnetic radiation with which the crystals interact more intensively. Repeated wavelength-dependent refraction of light at the regions of different refractive indices produces the color in the reflection or transmission of the photonic crystals. In this way, photonic band structures arise, which may have areas of forbidden energies, so that electromagnetic waves of specific wavelength can not propagate within the crystal.

Since the interaction of photonic crystals with light of different wavelengths depends on the corresponding refractive indices of the repetitive units or on their dimensions, the optical properties of the crystals can be adjusted or changed via this. We propose that the structure of photonic crystals should be such that, as the geometrical extent of the system changes, the spatial dimension of one or more repetitive units within the crystal changes, resulting in an analyte-dependent (in this case, strain) change of the optical Properties (eg absorption, color, fluorescence, phosphorescence, etc.) come. It does not matter with which method the photonic crystals were produced. In the following, the principle of sensor technology with photonic crystals will be exemplified by the chemical production with the aid of micro- and nanoparticles (see Fig. 5, "Chemical (colloidal) method of preparation of photonic crystals and their application as strain gauges, n = refractive index").

The application proposed here is not limited thereto. The underlying principles apply to all systems consisting of or containing photonic crystals, regardless of the materials used (metals, polymers, minerals, crystals, natural products, fabrics, paper, textiles, glass, crystalline or amorphous substances, etc .). Nanoparticles or microparticles are used in the chemical preparation process for colloidal photonic crystals (Species 1, FIG. 5). These may be inorganic, organic, metallic or polymeric particles (eg silica, polystyrene, polyvinyl chloride, cobalt, silver or gold particles, inorganic and organic pigments, so-called "upconverting nano particles", quantum dots, Semiconductors, to name just a few) and core / shell systems made of organic and / or inorganic components.The later optical properties of the photonic crystal can be adjusted by the refractive index of the material.For a given refractive index, the diameter of the particles, with The optionally modified particles are brought into a highly ordered structure (process A, FIG. 5), such as the hexagonal closest packing (see Species 2, FIG.

From this step, the material is optically active, ie it interacts with electromagnetic waves in the manner described above, since regions of different refractive indices (as in this case n _par , i _k ei and n air) repeat periodically. The resulting material can then be fixed in its structure by polymers (process B, FIG. 5). This may result in new optical properties (see Species 3, Fig. 5), since under certain circumstances, the ratios of the refractive indices change (np _art i _kd and np ₀ i _yme nAir). These photonic crystals fixed in their structure can be further modified, for example by selectively removing the particles used from the material (process C, FIG. 5) and thus generating periodic vacancies or gaps in the crystal (species 4, FIG. 5). , This may also result in new optical properties of the crystal, if the ratios of the refractive indices change as a result of the process. The diverse production methods of photonic crystals enable integration into existing manufacturing processes and allow their use in all areas of technology and applications. The functioning of photonic crystals is completely independent of the production method (chemically with particles or physically with methods of the semiconductor industry, etc.) and can thus be adapted as an instrument of optical sensor technology to the requirements of the respective application and the related processing and production methods , Exemplary manufacturing or. Processing methods include roll-to-roll, screen printing, inkjet printing, spray, dip and spin coating, injection molding, lithography, etching, hot stamping, anodizing and nanoimprinting, to name but a few.

An effect of the concept described here lies in the simplicity, diversity and in the clear signal effect. By means of photonic crystals it is possible to operate optical sensors without chromophore systems in the proper sense (i.e., without dyes, pigments). In this way, one has access to physical parameters such as compressive and tensile forces that can not yet be detected with optical sensors or test strips. The optical properties of the photonic crystals are adjustable by the nature and nature of the materials used and are not dependent on the chemistry of dyes. In addition, the desired measuring range can also be set by the nature of the crystals. The implementation of photonic crystals for the detection of tensile forces and strains impresses with simplicity and the optical signal effect. The exceeding or falling below of limit values can thus be displayed directly via a color change (for example from green to red). The choice of materials allows stepless adjustment of the measuring ranges, the sensitivity and the range of the color change. Due to the versatility of the manufacturing methods and the materials that can be used, photonic crystals can be integrated into almost every process and the associated products. As a result, measurement strips based on photonic crystals can be tailored to the needs of the application.

According to embodiments, optical strain gauges can thus be realized, which can indicate the prevailing forces and moments by color change. The above principle / concept of photonic crystals is also applicable to other materials or manufacturing methods.

Claims

claims

A medical stocking (100) comprising: a sock material (102); and a sensor element (10, 10 ', 104) attached to or in the sock material (102), wherein the sensor element (10, 10', 104) has a measurement area and a photonic crystal array (12) with an optical property, wherein the optical Property of the photonic crystal assembly (12) is changed by the action of a physical quantity on the photonic crystal assembly (12) within the measuring range, so that the change in the optical property is detectable when the change of the optical property occurs when the physical measured variable.

The medical stocking (100) of claim 1, wherein the medical stocking is a medical compression stocking or a medical thrombosis prophylaxis stocking.

The medical stocking (100) according to claim 1 or 2, wherein the sensor element (10, 10 ', 104) is attached to the surface of the sock material (102) in the form of a sticker or a sewn-on strip as a measurement strip or in the sock material (102 ) is entangled.

The medical stocking (100) of any one of claims 1 to 3, wherein the garment material (102) comprises threads or yarns having a photonic crystal arrangement such that the garment material (102) intrinsically comprises the sensor element and its optical strain measurement functionality.

5. Medical stocking (100) according to one of claims 1 to 4, wherein the physical measurement variable to be detected within the measurement range comprises a mechanical force acting in the tensile direction, pressure direction, as bending moment or as torsional moment.

The medical stocking (100) of any one of claims 1 to 5, wherein the optical properties are based on at least two alternating or multiple indices of refraction (ni, n ₂ , n ₃ , ri ₄ , num) within the photonic crystal array (12). A medical stocking (100) according to any one of claims 1 to 6, wherein the optical properties belong to the group comprising interference, refraction, diffraction, scattering, reflection, absorption, coloring, fluorescence, phosphorescence, bioluminescence, chemiluminescence and / or different refractive indices ( ni, n ₂ , n ₃ , ri 4, nma) in the photonic crystal arrangement (12).

The medical stocking (100) of any one of claims 1 to 7, wherein the optical properties are modifiable to cause a change in coloration, change in absorbance, fluorescence, phosphorescence, bioluminescence, or chemiluminescence.

The medical stocking (100) according to any one of claims 1 to 8, wherein the optical properties are due to introduced defects (24), introduced particles (12a, 12b, 12c, 12d, 12e, 12f, 12x) or by a biased crystal structure of the photonic crystal arrangement (12) are adjustable.

The medical stocking (100) of any one of claims 1 to 9, wherein a crystal structure of the photonic crystal array (12) is adjustable by a cladding (22) of the photonic crystal array (12).

The medical stocking (100) of claim 10, wherein the sheath (22) has a polymer structure configured to fix the crystal structure.

The medical stocking (100) of any one of claims 1 to 1 1, wherein the photonic crystal assembly (12) is disposed on a flexible substrate (19) on the sock material (102).

Medical bandage with a medical substrate (19); and a sensor element (10, 10 ') applied to the medical substrate (19), comprising: a photonic crystal array (12) having one or more optical properties due to its structure; and a plurality of receptor sites (14) integrated into the photonic crystal array (12) for selective interaction with analytes (16), wherein the optical properties of the photonic crystal array (12) are changeable based on the analytes (16) attached to the receptor sites (14) and / or based on direct chemical and / or physical interaction of the analytes (16) with the receptor sites (14).

The medical bandage of claim 13, wherein the receptor sites (14) are configured to selectively couple analytes (16) based on an interaction involving a protein-protein interaction in the form of an antibody-protein interaction, an antibody-antigen interaction , a DNA-RNA interaction, a DNA-DNA interaction, an RNA-RNA interaction, a DNA-protein interaction, an RNA-protein interaction or an enzyme-substrate interaction.

15. Medical bandage with a medical substrate (19); and a sensor element (10, 10 ') applied to the medical substrate (19), comprising: a measuring area; and a photonic crystal array (12) having an optical property, wherein the optical properties of the photonic crystal array (12) are changeable by applying a physical quantity to the photonic crystal array (12) within the measurement area such that the change in the optical property is detectable if the change in the optical property occurs when the physical quantity is affected.

16. The medical bandage according to claim 15, wherein the physical measurement quantity to be detected within the measurement range is a temperature, a current, a charge, a voltage, a magnetic field strength or a mechanical force which acts in the tensile direction, pressure direction, as bending moment or as torsional moment. includes.

17. Medical bandage according to one of claims 13 to 16, wherein the optical

Properties based on at least two alternating or multiple refractive indices (ni, n ₂ , n ₃ , n ₄ , n ^) within the photonic crystal arrangement (12). A medical bandage according to any one of claims 13 to 17, wherein the optical properties belong to the group, the interference, refraction, diffraction, scattering, reflection. Absorption, coloring, fluorescence, phosphorescence, bioluminescence, chemiluminescence and / or different refractive indices (ni, n ₂ , n ₃ , ri4, n _Lu ft) in the photonic crystal arrangement (12).

A medical bandage according to any one of claims 13 to 18, wherein the optical properties are modifiable to cause a change in coloration, a change in absorbance, fluorescence, phosphorescence, bioluminescence or chemiluminescence.

A medical bandage according to any one of claims 13 to 19, wherein the optical properties are adjustable by introduced defects (24), introduced particles (12a, 12b, 12c, 12d, 12e, 12f, 12x) or by a prestressed crystal structure of the photonic crystal assembly (12) are.

A medical bandage according to any one of claims 13 to 20, wherein a crystal structure of the photonic crystal array (12) is adjustable by a cladding (22) of the photonic crystal array (12).

The medical bandage of claim 21, wherein the sheath (22) has a polymer structure configured to fix the crystal structure.

A medical bandage according to any one of claims 13 to 22, wherein the photonic crystal array (12) is disposed on a rigid substrate (19) or a flexible substrate (19).

The medical bandage according to claim 23, wherein the rigid substrate (19) is a metallic carrier, a glass substrate or a polymer substrate or wherein the flexible substrate (19) is a paper substrate, textile substrate, polymer substrate or a film substrate.

25. A method for manufacturing a medical stocking (100) according to any one of claims 1 to 12, comprising the step: Applying or weaving the sensor element (10, 10 ', 104) into the sock material (102).

26. A method for manufacturing a medical bandage according to any one of claims 1 3 to 24, comprising the step:

Applying or weaving the sensor element (10, 10 ') into the dressing material.

27. The method according to claim 25 or 26, wherein the method comprises the following steps of producing the sensor element (10, 10 ', 104):

Arranging particles (12a, 12b, 12c, 12d, 12e, 12f, 12x) of a defined size so that a photonic crystal arrangement (12) is formed; and

Integrating receptor sites (14) for selectively interacting with analytes (16) in the photonic crystal array (12); or

Setting a measuring range in the photonic crystal arrangement (12).

28. The method of claim 25, wherein the method comprises the following steps of setting a measurement functionality of the sensor element (10, 10 ', 104):

Introducing defects (24) and / or particles (12a, 12b, 12c, 12d, 12e, 12f, 12x) into the photonic crystal array (12) to adjust at least two alternating or multiple indices of refraction (n _1? N ₂ , n ₃ , n ₄ , n air) within the photonic crystal array (12) by a crystal structure strained by the voids (24) or the particles (12a, 12b, 12c, 12d, 12e, 12f, 12x); and or

Biasing the crystal structure of the photonic crystal array (12) to adjust at least two alternating or multiple indices of refraction (ni, n ₂ , n ₃ , n ₄ , n air) within the photonic crystal array (12) by mechanical displacement of the crystal structure to adjust the optical property ,

29. Sensor element (10, 10 ', 104), having the following features: a measuring range; and a photonic crystal arrangement (12) having one or more optical properties, wherein the optical properties of the photonic crystal array (12) by changing a physical quantity on the photonic crystal array (12) are variable within the measuring range, so that the change of the optical property detectable is when the change in the optical property occurs when the physical measured variable acts, and wherein the physical measured variable to be detected within the measuring range comprises a temperature, an electrical current, an electrical charge, an electrical voltage or a magnetic field strength.

30 sensor element (10, 10 ', 104), comprising: a photonic crystal arrangement (12), which have one or more optical properties due to their structure; and a plurality of receptor sites (14) integrated into the photonic crystal array (12) for selectively interacting with analytes (16), the optical properties of the photonic crystal array (12) being based on the analytes (16) and receptor sites (14) / or are variable based on direct chemical and / or physical interaction of the analytes (16) with the receptor sites (14), and wherein a crystal structure of the photonic crystal array (12) is adjustable by a cladding (22) of the photonic crystal array (12), wherein the sheath (22) has a polymer structure configured to fix the crystal structure.

31. Sensor element (10, 10 ', 104), having the following features: a measuring range; and a photonic crystal arrangement (12) having an optical property, the optical properties of the photonic crystal arrangement (12) being variable by the action of a physical quantity on the photonic crystal arrangement (12) within the measuring range, so that the change in the optical property can be detected if the change in the optical property occurs when the physical measured variable acts, wherein a crystal structure of the photonic crystal array (12) is adjustable by a cladding (22) of the photonic crystal array (12), the cladding (22) having a polymer structure configured to fix the crystal structure.