KR101921315B1 - Fluorescent silk nanofibers sensor for detecting a noxious substance - Google Patents

Abstract

The present invention relates to a fluorescent silk nanofiber in which an optically active organic dye is doped in a silk nanofiber, and is characterized in that it is environmentally friendly and physically removed after a specific time by a doped organic dye with high sensitivity and visibility, And a disposable membrane for mass transfer or the like can be provided.

Description

[0001] The present invention relates to a fluorescent silk nanofiber sensor for detecting harmful substances,

The present invention relates to a fluorescent silk nanofiber sensor for the detection of harmful substances. More specifically, the present invention relates to silk nanofiber-based fluorescent silk nanofibers having properties that are environmentally friendly, have high sensitivity and visibility, and are physically removed at prescribed times, and a manufacturing method and use thereof.

Here, background art relating to the present disclosure is provided, and they are not necessarily meant to be known arts.

One-dimensional polymer nanofibers and their networks are characterized by high surface-to-volume ratios, porosity and permeability that are important in sensing, tissue engineering, drug delivery, protective clothing and filtration devices. do.

The electrospinning method used to produce nanofibers using polymers provides low cost, high manufacturing efficiency, as well as stiffness, strength, fiber diameter, And porosity can be controlled.

(Cellulosic, chitin, chitosan, etc.), proteins (such as silk, cotton, etc.) due to the sustainability, eco-friendly and renewability due to inherent characteristics such as biodiversity and biodegradability of polymer nanofibers , Collagen, gelatin, etc.) and DNA polymers.

In the fields of biology and biomedicine, nano-optics plays a notable role in imaging, sensing and therapy. Thus, by incorporating optical functionality into biopolymer nanofibers, it is possible to combine all the advantageous properties of nanofibers and biopolymer nanofibers.

On the other hand, there are various types of chemical sensors used in the industry for the detection of chemical or biological substances. These sensors can be fabricated using various materials and materials. For example, when a sensor is fabricated using a metal or metal compound, it must be removed after use, and it will not be removed for a long period of time and will adversely affect the environment.

In addition, optical sensing devices are also being manufactured for use in various analytical and commercial applications. Such optical sensing devices are also manufactured using materials that are not biodegradable, such as glass, fused silica, and plastics, and thus have a bad influence on the environment .

Silk has been widely used as a garment material due to its excellent strength and gloss. In recent years, efforts have been made to apply such silk as a clothing material, as well as to apply it as a high-value-added functional food and biotechnology material . BACKGROUND ART [0002] Silk has been actively studied worldwide for medical materials such as tissue scaffolds, artificial skin, and artificial ectoderm based on excellent properties of biocompatibility, blood compatibility, cell attachment and proliferation.

An object of the present invention is to provide a chemical sensor for detecting harmful chemical substances, which is excellent in detection performance by using silk and is not harmful to the environment.

1. Korean Patent No. 10-1346656 (Aug. 31, 2013) 2. Korean Patent No. 10-1636695 (June 30, 2016)

The present invention provides a fluorescent silk nanofiber comprising a combination of a matrix polymer of nanofibers and an optically functional dopant for suitably controlling the optical properties of the polymer, and a method for producing the fluorescent silk nanofiber.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

The present invention provides a fluorescent silk nanofiber in which an optically active organic dye is doped in a silk nanofiber including silk fibroin obtained by removing a sericin component from a silk.

The optically active organic dye may include at least one selected from the group consisting of rhodamine, sodium fluorescein, stilbene, and riboflavin .

The present invention also provides a fluorescent silk nanofiber sensor capable of detecting acid vapors using the fluorescent silk nanofibers.

The present invention also relates to a fluorescent silk ink production step (S1) of producing a fluorescent silk ink in which an optically active organic dye is mixed with a silk aqueous solution; And an electrospinning step (S2) of electrospinning using the fluorescent silk ink. The present invention also provides a method for manufacturing a fluorescent silk nanofiber.

The fluorescent silk ink preparation step (S1) includes a silk aqueous solution preparation step (S11) which is an aqueous solution containing fibroin which is separated by removing sericin from silk, a dye mixing step (S12) of mixing the optically active organic dye with the silk aqueous solution, And a control unit.

The silk aqueous solution preparation step (S11) is a step of preparing an aqueous silk solution such that the silk fibroin is contained in an amount of 5 to 10% by weight.

Further, the dye mixing step (S12) may include adding an additive to the silk aqueous solution so as to have a viscosity and a surface tension suitable for electrospinning to prepare a basic solution, and then adding the rhodamine, Wherein at least one selected from the group consisting of sodium fluorescein, stilbene, and riboflavin is mixed.

Further, in the dye mixing step (S12), the basic solution is prepared by mixing the silk aqueous solution and the additive at a volume ratio of 1: 0.8-1.2.

The dye mixing step (S12) is characterized by mixing the optically active organic dye in the basic solution at a concentration of 7 to 15 mM.

In the electrospinning step S2, the silk fluorescent ink is injected into a syringe equipped with a capillary, a voltage is applied between the capillary and a collector provided at a specific distance, and the injected silk fluorescent ink is injected into the collector , And the fluorescent silk nanofiber is dried in the air to produce the fluorescent silk nanofiber.

The electrospinning step S2 is characterized in that the distance between the capillary and the collector is 10 to 30 cm and the potential difference between the capillary and the collector is electrospinning at 5 to 15 kV to produce the fluorescent silk nanofibers .

Further, after the electrospinning step (S2), a crystallization step (S3) for controlling the crystallinity of the produced fluorescent silk nanofibers is further included.

The present invention provides a fluorescent silk nanofiber by using a silk fibroin as a biomolecular polymer as a matrix polymer and a water-soluble optically active organic dye as an optically functional dopant, thereby providing a fluorescent silk nanofiber that is environmentally friendly and has high sensitivity and visibility It can be suitably used for a fluorochemical sensor or a disposable membrane for mass transfer or the like.

1 is a schematic view of a method for manufacturing a fluorescent silk nanofiber according to an embodiment of the present invention.
2 is a fluorescence image of a fluorescent silk nanofiber according to an embodiment of the present invention.
FIG. 3 is a fluorescence spectrum and a scanning electron microscope image of a fluorescent silk nanofiber according to an embodiment of the present invention.
FIG. 4 shows daylight and ultraviolet (UV) irradiation images of fluorescent silk nanofibers according to an embodiment of the present invention.
FIG. 5 is a graph showing absorption and emission spectra of fluorosine-doped fluorescent silk nanofibers before and after exposure to hydrochloric acid vapor according to an embodiment of the present invention.
FIG. 6 is a graph showing changes in external color and fluorescence after the fluorescent silk nanofibers according to an embodiment of the present invention are exposed to hydrochloric acid vapor.
FIG. 7 is a graph showing changes in light emission and reaction rate after fluorescent silk nanofibers according to an embodiment of the present invention are exposed to hydrochloric acid vapor.
FIG. 8 shows a fluorescence spectrum of the fluorescent silk nanofiber according to an embodiment of the present invention after exposure to hydrochloric acid vapor.
9 is a graph showing a fluorescence spectrum after the fluorescent silk nanofibers according to an embodiment of the present invention are exposed to hydrofluoric acid vapor.
10 is a graph showing the results of solubility measurement of the fluorescent silk nanofibers according to an embodiment of the present invention by methanol vapor treatment.
FIG. 11 shows FT-IR absorption spectra of the fluorescent silk nanofibers before and after methanol vapor treatment according to an embodiment of the present invention.
Fig. 12 shows the confirmation of the use of an attachable disposable toxic agent in fluorescent silk nanofibers according to an embodiment of the present invention.
FIG. 13 shows confirmation of the use of an attachable skin-type toxicant-sensitive agent of a fluorescent silk nanofiber according to an embodiment of the present invention.
14 shows confirmation of the application of a fluorescent silk nanofiber to a mass transfer membrane according to an embodiment of the present invention.
FIG. 15 shows photoluminescence for confirming riboflavin transfer of a fluorescent silk nanofiber including riboflavin according to an embodiment of the present invention.

Before describing the present invention in detail, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is defined solely by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise stated.

Throughout this specification and claims, the word "comprise", "comprises", "comprising" means including a stated article, step or group of articles, and steps, , Step, or group of objects, or a group of steps.

On the contrary, the various embodiments of the present invention can be combined with any other embodiments as long as there is no clear counterpoint. Any feature that is specifically or advantageously indicated as being advantageous may be combined with any other feature or feature that is indicated as being preferred or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the accompanying drawings.

Fluorescent silk nanofibers (FSNs) according to an embodiment of the present invention are organic dye-doped silk nanofibers having water-soluble optical activity, and have biodegradability and physically temporal optical activity. The fluorescent silk nanofibers according to the present invention are produced by an electrospinning method using a fluorescent silk ink prepared by including a silk biopolymer and optically active organic dyes.

The fluorescent silk nanofiber according to the present invention uses a silk biopolymer as a matrix polymer. The silk matrix has physical properties such as biocompatibility, biodegradability and reproducibility and is therefore suitable for use in close proximity to the human body or for use in the human body.

More specifically, silk fibroin obtained by removing sericin components from silk is used. By using silk as a matrix polymer, optically active dopants such as drugs and dyes contained in silk nanofibers can be stably preserved.

Further, the fluorescent silk nanofiber according to the present invention can be removed at a specific time by controlling the crystallinity of the silk fiber by vapor-treating it with methanol.

The optically active organic dye may be at least one selected from the group consisting of rhodamine, sodium fluorescein, stilbene and riboflavin as a water-soluble organic dye .

Fluorescent silk nanofibers containing fluorene sodium as an organic dye have a sensing function for hydrochloric acid (HCl) vapor, which is a volatile hazardous substance. At this time, the concentration of the detectable hydrochloric acid vapor is 1 to 3000 ppm, and it is possible to detect even the low concentration of 5 ppm or less and detect the lethal concentration of 300 ppm or more when the human body is introduced.

Fluorescent silk nanofibers, including riboflavin as an organic dye, have nutrient transport into body tissues. Mass transfer effects can be observed by fluorescence tracing.

The fluorescent silk nanofibers according to the present invention have a uniform diameter and homogeneous fluorescence characteristics. The fluorescent silk nanofiber according to the present invention has a uniform diameter within an error range of +/- 10% within a range of 300 to 600 nm and has a fluorescence characteristic according to a doped optically active organic dye.

The method for producing fluorescent silk nanofibers according to an embodiment of the present invention includes a fluorescent silk ink production step (S1) and an electrospinning step (S2). FIG. 1 is a schematic view of a method of manufacturing a fluorescent silk nanofiber according to an embodiment of the present invention.

As shown in Fig. 1, the fluorescent silk nanofibers are produced by preparing a fluorescent silk ink in which a water-soluble optically active organic dye and polyethylene oxide are mixed in a silk aqueous solution, injecting the produced fluorescent silk ink into a syringe, ), And then a voltage is applied to the collector using a power supplier.

The fluorescent silk ink production step (S1) comprises a silk aqueous solution preparation step (S11) which is an aqueous solution containing fibroin which is separated by removing sericin from silk, a dye mixing step (S12) of mixing the optically active organic dye with the silk aqueous solution ) To produce an ink to be used for electrospinning.

The silk aqueous solution preparation step (S11) is a step of preparing an aqueous solution containing fibroin which is separated by removing sericin from silk. Silk fibroin has a high physiological activity as a peptide material in which a variety of amino acids (amino-acid) and a combination of its amino acids are mixed together as a constituent of a protein. Depending on the type of amino acid and the type of the amino acid contained, silk fibroin Can be extracted from the silkworm silk as a material that can be utilized as a silk.

Silk fibroin dissolves sericin, which forms the outer surface of silk thread, through a processing process, and obtains a protein called Fibroin, which is present in the silk fibroin, and hydrolyzes it by using various enzymes as a catalyst. Depending on the method of hydrolysis and filtration of residues, the amino acid composition and the molecular weight are different, and the characteristics of the silk fibroin are also different.

In the silk aqueous solution produced in the silk aqueous solution preparation step (S11), 5 to 10% by weight of silk fibroin is contained. More preferably, a silk aqueous solution containing 7 to 9% by weight of silk fibroin is preferably produced.

The silk aqueous solution preparation step (S11) may use silk fibers or a silkworm (Bombyx mori) cocoa. First, water and sodium carbonate (Na ₂ CO ₃ ) are added to silk fiber or silkworm cocoons and heated at 90 to 110 ° C for 20 to 30 minutes to remove sericin, thereby extracting silk fibroin having a molecular weight of 90 to 110 kDa.

The extracted silk fibroin is washed and dried and then dissolved in a lithium bromide (LiBr) solution and cultured in a 50 to 80 ° C oven for 3 to 5 hours. The cultured solution was dialyzed against distilled water at room temperature for 40 to 60 hours using a dialysis apparatus. The dialyzed solution is centrifuged at -5 ° C to 0 ° C for 10 to 30 minutes, and the impurities are removed to prepare a silk aqueous solution having a concentration of 5 to 10% by weight.

The dye mixing step (S12) is a step of adding an optically active organic dye to the prepared silicate aqueous solution at a concentration of 5 to 10% by weight to add an additive so as to have a viscosity and a surface tension suitable for electrospinning.

It uses a weight average molecular weight of polyethylene oxide (PEO) of less than (M _w) 900000 as an additive added to the aqueous solution of silk. The addition of polyethylene oxide can prevent the embrittilization of silk fibers derived from the non-aqueous β-sheet form.

The optically active organic dye to be mixed into the silk aqueous solution may be at least one selected from the group consisting of rhodamine, sodium fluorescein, stilbene and riboflavin. do.

In the dye mixing step (S12), a basic solution is prepared by mixing the silk aqueous solution having the concentration of 5 to 10% by weight and the polyethylene oxide solution having the concentration of 3 to 7% by weight at a ratio of 1: 0.8-1.2. The diameter of the nanofibers prepared by controlling the content of PEO within the above range can be controlled within the range of 300 to 600 nm.

Next, the optically active organic dye is mixed at a concentration of 7 to 15 mM in the prepared basic solution to prepare a silk fluorescent ink.

 The electrospinning step (S2) is a step of obtaining fluorescent silk nanofibers by electrospinning using the silk fluorescent ink. Unlike the conventional melt spinning or solution spinning which uses pressure to produce fibers, an electric force It is possible to form fibers.

That is, in the present invention, when a high voltage is connected to the spinning stock solution and a voltage of 0 V or an opposite charge is applied to the spinning source at a distance from the spinning stock solution, the spinning stock solution moves due to the voltage difference, , The fluorescent silk nanofiber is produced using the principle that the fibers are formed when the melt is cooled and reaches the collecting plate.

The electrospinning step S2 first injects the prepared silk fluorescent ink into a syringe equipped with a capillary tube made of steel and applies a voltage between the capillary and the lower metal collector. The injected silk fluorescent ink is sprayed onto a metal plate by a pump and extended by electrostatic repulsion as it is dried in air to be collected on a metal plate as nanofibers. At this time, it is preferable to use an aluminum foil as a metal plate to easily separate the silk nanofibers from the metal plate at low cost. By spinning FSN on an aluminum foil, it has the advantages of flexibility, adaptability and easy processability.

In the electrospinning step S2, the distance between the capillary (or tip) and the metal plate (or collector) is 10 to 30 cm, the flow rate of the silk fluorescent ink is 5 to 15 μl / min, 30 minutes to 2 hours, and the potential difference between the tip and the collector is electrospinning under the condition of 5 to 15 kV to produce a fluorescent silk nanofiber having a uniform diameter within an error range of +/- 10% within a range of 300 to 600 nm do.

In addition, the method for fabricating a fluorescent silk nanofiber according to an embodiment of the present invention may further include a crystallization step (S3) to control the crystallinity of the produced fluorescent silk nanofiber so as to control the removal time after use.

The crystallization step (S3) is a step of treating with a methanol solution, methanol vapor or water vapor. In the case of using a methanol solution, the fluorescent silk nanofibers prepared in a methanol solution at room temperature are immersed and maintained for a certain period of time. When methanol vapor is used, methanol is introduced into a closed container at room temperature, The fabricated fluorescent silk nanofiber is immobilized, and the vaporized methanol vapor and the fluorescent silk nanofiber are reacted within 3 days. When using water vapor, the water vapor is subjected to temperature-controlled water vapor annealing (TCWVA) in a vacuum chamber at a constant temperature.

The fluorescent silk nanofiber according to the present invention can be used as a chemical sensor capable of detecting an acid or a base in a vapor state. The fluorescent silk nanofiber according to the present invention is environmentally friendly and has high sensitivity and visibility due to its luminescent characteristics, and thus can be suitably used for detecting harmful substances.

In particular, since fluorescein sodium exhibits strong pH dependency in fluorescence and absorption due to the occurrence of protolytic reactions in the excited state, the fluorescent silk nanofibers containing fluorene sodium exhibit a strong affinity for hydrochloric acid vapor Can be suitably used for sensing.

Also, the fluorescent silk nanofiber according to the present invention can be used as a disposable membrane for mass transfer.

Example

(1) Preparation of aqueous silk solution

Bombyx mori Kochi was boiled in an aqueous solution of 0.02 M sodium carbonate (Na ₂ CO ₃ ) for 30 minutes to remove silk fibroin by removing the sericin protein. The extracted silk fibroin was rinsed with distilled water for 20 minutes three times and dried for one day. After drying, silk fibroin was dissolved in 9.3 M LiBr solution and incubated in an oven at 60 ° C for 4 hours.

This solution was dialyzed against distilled water at room temperature for 48 hours using a dialysis cassette (Cellu-Sep T1, Membrane Filtration Products, MWCO 3.5K). The obtained solution was centrifuged at -1,000 캜 for 20 minutes at 9,000 rpm to remove impurities. This procedure was repeated twice to obtain a silk fibroin aqueous solution. The final concentration of the obtained aqueous solution of silk fibroin was about 8% by weight.

(2) Electrospinning process for the production of fluorescent silk nanofibers

Polyethylene oxide (PEO, Mv ~ 900,000, Sigma-Aldrich) was added to the aqueous silk fibroin solution to adjust the viscosity and surface tension suitable for electrospinning. A basic solution was prepared by mixing 5 wt% PEO solution and 8 wt% silk solution at a ratio of 1: 1. The active dye was mixed with a basic solution at a concentration of 10 mM to prepare a fluorescent silk ink.

As active dyes, stilbene 420 (Exciton), Fluorescein sodium salt (Sigma-Aldrich), Riboflavin 5'-monophosphate sodium salt hydrate (Sigma-Aldrich) and Rhodamine B , Sigma-Aldrich).

The fabricated fluorescent silk ink was injected into a syringe and placed on an electrospinning device. An aluminum foil was used as the collection screen. The distance between the tip and the collector was 20 cm, and the flow rate of bio-ink was set at 10 [mu] l / min. A 10 kV potential was applied between the 21 G nozzle tip and the collector during the electrospinning time between 30 minutes and 2 hours. The finally produced fluorescent silk nanofibers had a uniform diameter of 300-350 nm.

(3) Preparation and concentration control of HCl vapor environment

To produce the HCl vapor environment in ppm scale, liquid HCl was added to the beaker with a micropipette. After the beaker was sealed, the liquid HCl was completely evaporated by allowing it to stand at room temperature for 2 hours. For a concentration of 1 ppm (v / v), the volume ratio of HCl vapor to beaker volume was adjusted to 1 μL / L. By evaporating 1.63 μg of liquid HCl, 1 μL of HCl vapor, calculated from molar mass to molar volume ratio, was obtained at room temperature.

As an example, a fluorescent silk nanofiber mat was prepared as an indicator attached to a disposable skin type patch or clothing or protective equipment.

Experimental Example

(1) Fluorescence microscope image

Fluorescence microscope system (TCS SP8) manufactured by LEICA was used to obtain fluorescence images of fluorescent silk nanofibers containing sodium fluorescein according to an embodiment of the present invention. A sample of the fluorescent silk nanofiber was irradiated with an argon laser in the 488 nm band to measure light corresponding to a wavelength of 505-600 nm in fluorescence emitted from the sample. The measurement magnification is 400 times.

As shown in FIG. 2, the fluorescent silk nanofibers in which fluorescein sodium having the maximum fluorescence at 535 nm is mixed show homogeneously green fluorescence emission from the uniformly distributed fibers, and thus it is confirmed that the fluorescence silk nanofibers have excellent fluorescence characteristics. This indicates that the dye molecules are uniformly distributed in the silk matrix after the electrospinning process.

(2) Fluorescence spectrum and scanning electron microscope image

Fluorescence spectra of the fluorescent silk nanofibers prepared according to the embodiment of the present invention were measured. Fluorescence spectra were measured using a vis / near-infrared spectrometer (iHR-320, HORIBA Jobin Yvon) and examined using a 325 nm He-Cd continuous wave (CW) laser. In order to excite the fluorescent silk nanofibers over a large area, the irradiation point of the laser was extended using an optical lens with a focal length of 5 cm.

Fluorescent silk nanofibers containing sodium fluorescein, riboflavin, stilbene 420 and rhodamine B as shown in Figs. 3 (a) to 3 (d) show emission peaks at wavelengths of 535 nm, 540 nm, 435 nm and 585 nm, respectively The fluorescence properties of the fluorescent silk nanofibers are consistent with the intrinsic properties of the organic dyes contained therein.

The fluorescent silk nanofibers prepared according to the examples of the present invention were observed by scanning electron microscopy (SEM) using S-4800 (Hitachi) to observe the structure of the fluorescent silk nanofibers and to evaluate the diameter of the fibers ) Images.

It can be seen that all the fluorescent silk nanofibers are uniformly formed in diameter as shown in Figs. 3E to 3H. The average diameter of the fluorescent silk nanofibers measured by SEM images was 300 to 350 nm.

(3) Daylight and ultraviolet (UV) irradiation

The fluorescent silk nanofiber mat may be used as a color converter such as phosphors for light emitting diodes (LEDs). FIG. 4 shows three kinds of fluorescent silk nanofibers, "AJOU" doped with rhodamine B, "UNIV" doped with fluorescein sodium, and "NBOL" doped with stilbene 420. To represent the characters, the fluorescent silk nanofiber mat was placed behind a shadow mask using black paper.

As shown in FIG. 4A, the fluorescent silk nanofibers exhibited pink, yellow, and white colors, respectively, during daylight irradiation. Even when irradiated with a 325 nm He-Cd laser, as shown in 4b, orange-red (fluorescent peak wavelength, λ _peak ~ 585 nm) of the green (λ _peak ~ 525 nm), blue light (λ _peak ~ 435 nm) A uniform fluorescence was observed.

(4) Assessment of hazardous substance detection performance

FIG. 5 shows absorption and emission spectra of fluorescent silk nanofibers doped with fluorene sodium before (solid line) and after (dotted line) before exposure to hydrochloric acid vapor. While the absorption spectrum (blue) was shifted, the emission spectrum (green) decreased in intensity at the same wavelength. In addition to lowered fluorescence (which can be used for fluorescence chemical sensing), the change in color of the fluorescent silk nanofibers with shifting of the absorption peaks can be an excellent indicator of the detection of hydrochloric acid.

Fluorescein sodium doped fluorescent silk nanofibers were also exposed to vaporized hydrochloric acid at various concentrations (300, 500, 1300, 3000 ppm).

6A shows the external color and fluorescence change of fluorescent silk nanofibers exposed to 300 ppm hydrochloric acid vapor (10 minutes RD ₅₀ value). As the exposure time increased, the fluorescence color shifted from light green (λ _peak = 535 nm) to dark green (λ _peak = 510 nm), while external light under daylight changed from bright yellow to light green.

Also, FIG. 6b shows the fluorescent hue of the fluorescent silk nanofibers when exposed for 2 seconds at various concentrations. As the concentration of hydrochloric acid vapor increases, the response becomes faster and clearer.

In addition, the changes in photoluminescence and reaction rate were compared in the lethal concentrations of RD ₅₀ (300 ppm, mouse), LC _{LO, 30 min} (1300 ppm, human), LC _{LO, 5 min} (3000 ppm, human). As shown in FIG. 7, it takes about 18 seconds at 300 ppm, 13 seconds at 3000 ppm and 2 seconds at 3000 ppm until completely deteriorated by fluorescence, and FSNs are immediately eroded by hydrochloric acid vapor at all concentrations .

Also, the reaction at low concentration was confirmed. FIG. 8 shows the fluorescence spectrum of the FSN chemical sensor after 5 minutes of exposure to HCl vapors of 0, 5, 10 and 100 ppm. As shown in FIG. 8, even at low ppm concentrations, the FSN sensor showed a detection signal within a few minutes, which means that it can secure sufficient time to take safety measures.

Also, as shown in FIG. 9, it is confirmed that the same FSN sensor can detect hydrofluoric acid vapor corresponding to a fatal substance in the human body.

(5) Measurement of solubility of fluorescent silk nanofibers

The solubility depends on the crystallinity of the silk molecule and can determine the life cycle of the silk sensor. It can be seen that the fluorescent silk nanofiber according to the present invention is easily soluble in water because of its low crystallinity as shown in Fig. The methanol vapor treatment improves the crystallinity of the secondary structure of the silk (β-sheet), and the longer the methanol vapor treatment is, the more FSNs remain after washing the aluminum foil.

Polymorphic transitions are correlated with water solubility, which can be analyzed by FT-IR (Fourier Transform Infrared Spectroscopy). As shown in Fig. 11, the untreated FSN is detected by resonance absorption at 1647 cm < ^-1 > by the random coil configuration of a typical amorphous protein. After FSN treatment with methanol vapor for 3 days, a clear peak at 1625 cm ^-1 was detected by the structure of the β-sheet silk fiber.

(6) Confirmation for the use of disposable and skin-type toxic substances

The fluorescent silk nanofibers according to the present invention were easily attached to work clothes or protective equipment and used as a danger indicator. In FIG. 12A, rectangular pieces of FSNs were attached to experimental gloves from left to right with sodium fluorocarbons, riboflavin, and stilbene as HCl sensing agents. After exposure of the FSNs to HCl vapor for 1 minute, the FSN containing fluorescein sodium showed fluorescence properties as shown in Figure 12b, but the FSN containing riboflavin and stilbene did not react to the HCl vapor. Also, as shown in Figure 12C, the FSN used can be rinsed off with water without environmental contamination.

Also, the FSN mat can be used as a disposable skin type sensor which can be covered on the skin as shown in Fig. As shown in FIG. 13A, a mat made of fluorescent silk nanofibers including sodium fluorescein can be attached to the skin to be used as a sensor for detecting a harmful substance. As shown in FIG. 13B, water can be used for quick and easy removal Do.

(7) Confirmation of use of mass transfer membrane

Fluorescent silk nanofibers according to the present invention can be utilized as a biological tissue carrier containing a medicament due to their high surface to volume ratio. Due to the biocompatibility of silk fibroin, FSN can be transplanted and reabsorbed. In addition, the fluorescence of the doped functional material can simultaneously perform the function of identifying the mass transfer while imaging it.

In this experiment, riboflavin-doped fluorescent silk nanofibers were modeled and reproduced as a delivery system for nourishing the skin. Riboflavin, known as vitamin B2, is known to be effective in skin care, such as acne and sebum management.

14A and 14B, a riboflavin-doped FSN mat was placed on a biological tissue (chicken breast). Since the riboflavin is extracted from the water contained in the living tissue and the fluorescent silk nanofibers may be dissolved in the process, FSN is crystallized through methanol vapor in advance to stabilize the network of the silk matrix. Riboflavin, which had been doped onto the mat for 2 seconds, was dispersed to the tissue surface, after which the FSN mat was separated from the tissue.

The delivered riboflavin could be identified by observing fluorescence under UV exposure. FIGS. 14C and 14D show photographs in which biotissues are excited by a UV light source. FIG. The optical portion of riboflavin (FIG. 14C) and the portion of untransfected riboflavin (FIG. 14D) were optically compared and it was confirmed that the green fluorescence of riboflavin was observed at the point where riboflavin was transferred.

When comparing the fluorescence intensity of FSN before and after riboflavin transfer, the amount of delivered riboflavin can be quantified. As shown in FIG. 15, the fluorescence of the FSN mat containing riboflamin was significantly reduced to 60% for 2 seconds, indicating that the appearance of the riboflavin dye changed whitish as it exited.

The features, structures, effects, and the like illustrated in the above-described embodiments can be combined and modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

Claims (13)

It is possible to detect the acid vapor in the range of 1 to 3000 ppm by using the fluorescent silk nanofiber in which the optically active organic dye is doped in the silk nanofiber,
Fluorescent silk capable of detecting acid vapors through color change of fluorescent silk nanofibres due to shift of absorption spectrum and intensity of emission spectrum in measurement of absorption and emission spectra of the fluorescent silk nanofibers Nanofiber sensors.
The method according to claim 1,
Wherein the silk nanofiber includes silk fibroin obtained by removing a sericin component from a silk.
The method according to claim 1,
Wherein the optically active organic dye comprises at least one selected from the group consisting of rhodamine, sodium fluorescein, stilbene, and riboflavin. Silk nanofiber sensors.
delete A method for producing the fluorescent silk nanofiber sensor of claim 1,
(S11) which is an aqueous solution containing fibroin which is separated by removing sericin from silk, and an additive is added to the silk aqueous solution so as to have a viscosity and a surface tension suitable for electrospinning to prepare a basic solution, A fluorescent silk ink production step (S1) of producing a fluorescent silk ink in which an optically active organic dye is mixed with a silk aqueous solution, including a dye mixing step (S12) of mixing an optically active organic dye; And
And an electrospinning step (S2) of electrospinning using the fluorescent silk ink,
In the dye mixing step (S12), the basic solution is prepared by mixing the silk aqueous solution and the additive at a volume ratio of 1: 0.8-1.2,
Wherein the dye mixing step (S12) comprises mixing the optically active organic dye in the basic solution at a concentration of 7 to 15 mM.
delete 6. The method of claim 5,
Wherein the silk aqueous solution preparation step (S11) is a step of preparing a silk aqueous solution such that the fibroin is contained in an amount of 5 to 10% by weight.
6. The method of claim 5,
Wherein the optically active organic dye is a mixture of at least one selected from the group consisting of rhodamine, sodium fluorescein, stilbene, and riboflavin. A method for manufacturing a silk nanofiber sensor.
delete delete 6. The method of claim 5,
The electrospinning step S2 injects the fluorescent silk ink into a syringe provided with a capillary tube, applies a voltage between the capillary tube and a collector provided at a specific distance, and injects the fluorescent silk ink into the collector Wherein the step of preparing the fluorescent silk nanofiber sensor is a step of producing a fluorescent silk nanofiber sensor as it is sprayed and dried in the air.
12. The method of claim 11,
Wherein the electrospinning step S2 is a step of preparing a fluorescent silk nanofiber sensor by electrospinning the capillary and the collector at a distance of 10 to 30 cm and a potential difference between the capillary and the collector at 5 to 15 kV Method of manufacturing a fluorescent silk nanofiber sensor.
6. The method of claim 5,
Further comprising a crystallization step (S3) of regulating the crystallinity of the fabricated fluorescent silk nanofiber sensor after the electrospinning step (S2).

Images