A biosensing method based on guided-mode resonance super surface and application thereof

Abstract

The application relates to the technical field of biosensors, in particular to a biosensing method based on a guided-mode lattice resonant super surface and application thereof. The biosensing method based on the guided-mode lattice resonant super surface comprises the following steps: step one: providing a guided-mode lattice resonant super surface and a light source; step two: realizing specific combination of biomolecules; and step three: detecting an optical signal and determining the concentration of target molecules. The method solves the problems that the existing surface lattice resonant super surface biosensor is difficult to realize high-Q value resonance in a discontinuous refractive index environment and is low in sensitivity to environmental refractive index changes.

Description

Technical Field

[0001] This invention relates to the field of biosensor technology, and more specifically to a biosensing method and its application based on a guided-mode lattice resonance metasurface. Background Technology

[0002] Biosensors are devices that convert the specific recognition of biomolecules into measurable signals, and are widely used in disease diagnosis, environmental monitoring, and food safety. In medical research, early disease diagnosis has always been a crucial issue. Biomarkers contain a wealth of disease-related data, and changes in their expression levels are often closely related to disease progression. Therefore, the detection of protein biomarkers has become an indispensable molecular diagnostic method in early disease diagnosis. With the development of nanotechnology, nano-optical biosensors have attracted widespread attention due to their high sensitivity, rapid response, and miniaturization. Among them, surface lattice resonance (SLR) metasurface biosensors utilize the collective oscillations of periodic nanostructures to improve the sensor's quality factor, exhibiting excellent detection performance. Surface lattice resonance metasurfaces possess outstanding characteristics such as high signal intensity, high quality factor (Q value), and large near-field gain, making them one of the important platforms for the development of metasurface biosensors. Among these, metasurface biosensors based on the refractive index measurement principle have become one of the important research directions in the field of metasurface biosensors due to their simple structure, wide adaptability, and quantitative detection capabilities. However, traditional surface lattice resonance metasurface biosensors still face some challenges in practical applications, such as difficulty in achieving high Q-value resonance in discontinuous refractive index environments and low sensitivity to changes in environmental refractive index.

[0003] To address the aforementioned issues, this invention designs a planar waveguide structure consisting of a substrate, a bio-modified layer, and a working medium. By combining this with the guided-mode lattice resonance effect of a periodic nanostructure array, it achieves high Q-value resonance under discontinuous refractive index conditions. Simultaneously, it amplifies the refractive index response signal and enhances detection sensitivity through the core layer thickness variation caused by biomolecule bonding. This clarifies the correspondence between the invention's objectives and the deficiencies of existing technologies. Summary of the Invention

[0004] This invention aims to address the problems of existing surface lattice resonance metasurface biosensors, such as difficulty in achieving high Q-value resonance in discontinuous refractive index environments and low sensitivity to changes in environmental refractive index. It proposes a biosensing method based on guided mode lattice resonance metasurfaces and its applications.

[0005] The technical solution adopted in this invention is:

[0006] A biosensing method based on a mode-guided lattice resonance metasurface includes the following steps:

[0007] Step 1: Provide a mode-guided lattice resonance metasurface and a light source;

[0008] A guided-mode lattice resonance metasurface is provided, the metasurface comprising a substrate, a biomodification layer, and a nanostructure array, wherein the substrate, the biomodification layer, and the surface working medium constitute a planar waveguide, and the surface working medium is air, an aqueous solution, or other biocompatible liquid capable of carrying target biomolecules without destroying their activity; a light source is provided to irradiate the metasurface;

[0009] Step 2: Achieve specific binding of biomolecules;

[0010] The metasurface is immersed in a solution containing target biomolecules or exposed to an air environment containing target molecules, so that the bioprobe molecules specifically bind to the target biomolecules, resulting in a change in the thickness of the biomodification layer of the metasurface.

[0011] Step 3: Detect the optical signal and determine the concentration of the target molecule;

[0012] The wavelength shift of the guided mode lattice resonance peak of the metasurface is measured, and the concentration of the target molecule is determined based on the relationship between the wavelength shift and the target molecule concentration; or the change in the intensity of transmitted / reflected light in a fixed band near the resonance peak is measured, and the concentration of the target molecule is determined based on the relationship between the change in light intensity and the target molecule concentration; the above method of measuring optical signals and determining the target molecule concentration is the detection method.

[0013] Preferably, the substrate has a single or multi-layer structure and is made of a solid material.

[0014] Preferably, the biomodification layer includes bioprobe molecules and a connecting material for connecting the bioprobe molecules to the substrate, wherein the bioprobe molecules include, but are not limited to, nucleic acid aptamers, antibodies, or small molecule ligands.

[0015] Preferably, the nanostructure array is a nanopore array, a nanoparticle array, or a combination thereof.

[0016] Preferably, the light source is a broadband light source, and the detection method is used to measure the wavelength change of the guided mode lattice resonance peak of the metasurface.

[0017] Preferably, the light source is a single-wavelength light source, and the detection method is used to measure the changes in transmitted and reflected light intensity in different partitions of the metasurface.

[0018] Preferably, the guided mode lattice resonance metasurface comprises multiple partitions, and the biological probe molecules modified on the metasurfaces of different partitions may be the same or different.

[0019] Preferably, the wavelength variation of the resonance peak of the guided mode lattice resonance metasurface satisfies the Hill-Language equation with respect to the concentration of the target biomolecule.

[0020] Preferably, the change in the intensity of the transmitted / reflected light in the fixed wavelength band satisfies the Hill-Language equation with respect to the concentration of the target biomolecule.

[0021] The guided-mode lattice resonance metasurface was obtained through the following design and fabrication method:

[0022] Step 1: Place the silicon wafer used for photolithography into an organic solvent and then into deionized water for cleaning and drying; the organic solvents are acetone and ethanol, respectively, and the cleaning time is 10 minutes.

[0023] Step 2: Vacuum deposition is used to deposit chromium, gold, silicon dioxide, and silicon nitride thin films onto the cleaned silicon wafer; the deposition method is electron beam evaporation deposition, and the deposition thickness is 10nm for chromium, 100nm for gold, 50nm for silicon dioxide, and 200nm for silicon nitride.

[0024] Step 3: Spin-coat electron beam photoresist onto the coated silicon wafer, and then heat it on a hot plate to remove the photoresist solvent; the photoresist is 495A4PMMA, the spin-coating speed is set to 2500 rpm and the time is 45s, the heating temperature is 100℃ and the heating time is 90s, and the photoresist thickness is about 200nm.

[0025] Step 4: Expose the silicon wafer to photoresist using an electron beam lithography machine, and then develop it with a developer; after development, the resulting hole diameter is approximately 200 nm, the array period is Px=Py=1020 nm, and the number of nanopores in the array is 200×200.

[0026] Step 5: Vacuum deposition of aluminum oxide is performed on the surface of the developed sample using vacuum deposition; the deposition method is electron beam evaporation deposition, and the deposition thickness is 100 nm for aluminum oxide.

[0027] Step 6: Remove the photoresist with acetone to obtain an array of aluminum oxide particles;

[0028] Step 7: Remove silicon dioxide and silicon nitride using dry etching; the etching method is reactive ion etching.

[0029] Step 8: Remove unreacted aluminum oxide with an acidic solution to obtain a metasurface; the acidic solution is a 1M aqueous solution of phosphoric acid.

[0030] Step 9: Place the prepared sample under ultraviolet light for irradiation, then clean it with deionized water and dry it with nitrogen gas; the irradiation time is 10 minutes and the cleaning time is 10 minutes.

[0031] Step 10: Immerse the cleaned sample in an aqueous solution of 4-mercaptobenzoic acid and let it stand at a low temperature; the concentration of the aqueous solution of 4-mercaptobenzoic acid is 5 mM, the standing temperature is 4℃, and the standing time is 12 h.

[0032] Step 11: Remove the sample from the solution, rinse with deionized water and dry with nitrogen gas;

[0033] Step 12: Place the sample in equal volumes of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride solution and N-hydroxysuccinimide solution, and let it stand; the 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride solution is 2 ml, the N-hydroxysuccinimide solution is 5 ml, and the standing time is 1 h;

[0034] Step 13: Rinse the sample with deionized water, then add nucleic acid aptamer solution to cover the gold film surface of the nanoparticle array region. Place the sample in a sealed petri dish and let it stand in the dark for 12 hours.

[0035] Step Fourteen: Rinse off any remaining nucleic acid aptamer molecules with deionized water, then cover with ethanolamine solution to allow the amino groups of ethanolamine to bind with the unbound carboxyl groups, thus completing passivation; the ethanolamine solution is 100 ml, and the covering time is 20 min.

[0036] The biosensor based on guided-mode lattice resonance metasurface prepared in this invention can be used for the detection of specific proteins, small molecules, etc., and has the following advantages compared with the prior art:

[0037] High sensitivity and high Q value: Through the design of the guided mode lattice resonance metasurface, a high Q value resonance is achieved in a discontinuous refractive index environment, which significantly improves the sensitivity and signal-to-noise ratio of the sensor;

[0038] Specific detection: By utilizing the specific binding of biological probes to target biomolecules, highly selective detection of specific biomolecules is achieved. Multi-channel design further improves detection efficiency;

[0039] Miniaturization and integration: Metasurface structures are simple, easy to fabricate and integrate, making them suitable for developing miniaturized, portable biosensors to meet the needs of point-of-care testing (POCT);

[0040] Wide range of applications: The biosensing method of the present invention is applicable to the detection of a variety of biomolecules, including proteins, nucleic acids, and small molecules, and has broad application prospects. Attached Figure Description

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0042] Figure 1 Flowchart for the fabrication of a gold mirror-gold nanoparticle array metasurface;

[0043] Figure 2 This is a scanning electron microscope image of a gold mirror-gold nanoparticle array metasurface.

[0044] Figure 3 Flowchart of fabrication process for aptamer-gold mirror-gold nanoparticle array guided mode lattice resonance biosensor;

[0045] Figure 4 A schematic diagram illustrating the structure and principle of an aptamer-gold mirror-gold nanoparticle array guided mode lattice resonance biosensor.

[0046] Figure 5 Reflectance spectra and center wavelengths during the modification of MoS2, lipoic acid and aptamers: (a) Reflectance spectrum; (b) Center wavelength;

[0047] Figure 6 The sensor's detection results for IFN-γ are shown in (a) transmission spectrum and (b) relationship between wavelength shift and concentration.

[0048] Figure 7 A schematic diagram illustrating the structure and principle of an aptamer-gold nanopore array guided mode lattice resonance biosensor.

[0049] Figure 8 Transmission spectra before and after modification of 4-mercaptobenzoic acid and after aptamer modification are shown in (a); transmission spectrum before fitting; and (b) transmission spectrum after fitting.

[0050] Figure 9 The sensor's detection results for IL-6 are shown in (a) transmission spectrum and (b) relationship between wavelength shift and concentration.

[0051] Figure 10 The sensor's detection results for CRP are shown in (a) transmission spectrum and (b) relationship between wavelength shift and concentration.

[0052] Figure 11 This is a schematic diagram of the fabrication process of a graphene-gold nanopore array metasurface biosensor (in sequence: metasurface preparation, graphene transfer, PBA modification, cleaning and drying).

[0053] Figure 12 This is a schematic diagram of the detection optical path;

[0054] Figure 13 The result is the glucose detection result (the curve showing the relationship between transmitted light intensity and glucose concentration). Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0056] Example 1:

[0057] The fabrication experiment of thick gold mirror-gold nanoparticle array metasurface, the fabrication process is as follows: Figure 1 As shown, it includes the following steps:

[0058] Step 1: Irradiate the nanopore array template silicon wafer with a UV lamp to make it hydrophilic, and then spin-coat dimethylammonium chloride (PDAC) as a release agent.

[0059] Step 2: Vacuum thermal evaporation is used to deposit 5nm copper and 100nm silver onto the template.

[0060] Step 3: Immerse the silicon template with silver nanofilm in water to demold it, and use a gold-plated substrate to retrieve it as a template for the nanoparticle array.

[0061] Step 4: Dry the silver nanomembrane template under vacuum at room temperature for 24 hours, and then deposit 1 nm of chromium and 50 nm of gold by vapor deposition.

[0062] Step 5: After etching the silver nanofilm with ferric nitrate aqueous solution, a thick gold mirror-gold nanoparticle array metasurface is obtained.

[0063] Scanning electron microscope images of the prepared metasurface are as follows: Figure 2 As shown, the gold nanodisks have a diameter of 180 nm and a height of 20 nm, with lattice constants px = 600 nm and py = 550 nm. Although the edges of the gold nanodisks are slightly irregular, the dimensions are not significantly different, and the deviation of the center position is small.

[0064] The fabrication experiment of the aptamer-gold mirror-gold nanoparticle array guided mode lattice resonance biosensor, the fabrication process is as follows: Figure 3 As shown, it includes the following steps:

[0065] Step 1: Spin-coat SU8 photoresist onto the metasurface sample and cure it with a UV lamp.

[0066] Step 2: Transfer the monolayer MoS2 to the metasurface surface.

[0067] Step 3: Modify the surface of MoS2 with lipoic acid, then activate it with EDC / NHS, and react it with amino-modified IFN-γ aptamer for 12 hours to form covalent bonds for fixation.

[0068] Step 4: Expose the sensor to a PBS solution containing IFN-γ and let it stand for 10 minutes. The aptamer specifically binds to IFN-γ, resulting in an increase in core thickness.

[0069] Step 5: Remove the sensor, rinse with deionized water, and dry with nitrogen. The aptamer-gold mirror-gold nanoparticle array guided mode lattice resonance biological structure and principle are as follows: Figure 4 As shown.

[0070] During the preparation process, the metasurface was characterized by reflectance spectroscopy to ensure the success of each modification step. The results are as follows: Figure 5 As shown in the figure, the reflectance spectra of the three stages reveal that after transferring MoS2, modifying lipoic acid, and modifying the aptamer, the resonance peaks all exhibited a "redshift" compared to their previous positions, shifting towards longer wavelengths. This indicates a change in the core layer thickness of the metasurface, meaning that MoS2, lipoic acid, and the aptamer have all been modified to the metasurface surface. The wavelength shift after aptamer modification is greater than that after lipoic acid modification, a result consistent with the fact that the molecular weight of lipoic acid is smaller than that of the aptamer. The gold mirror-gold nanoparticle array biosensor was successfully fabricated.

[0071] The IFN-γ concentration detection experiment includes the following steps:

[0072] Step 1: Dissolve IFN-γ dry powder in PBS solution according to the specified ratio to prepare a 10 μM standard solution.

[0073] Step 2: Dispense the prepared standard solution into centrifuge tubes and freeze it at -20°C.

[0074] Step 3: Take a sample of standard solution, thaw it, and dilute it with PBS solution to a 1 μM solution. Then, prepare test solutions ranging from 10 pM to 1 μM according to a certain concentration gradient.

[0075] Step 4: Use a pipette to add 30 μL of the test solution to the sensor, let it stand for 10 min to react, and after the reaction is complete, rinse with plenty of deionized water and blow dry with nitrogen.

[0076] Step 5: Clamp the sensor in the optical path and measure the transmission spectrum.

[0077] Spectroscopic measurement results of solutions at different concentrations are as follows Figure 6 As shown in (a), with the increase of IFN-γ concentration, the resonance peak of the TM0 mode also exhibited a "redshift" phenomenon. The center wavelength of the resonance peak gradually shifted from 706.15 nm to 709.11 nm, while the amplitude and quality factor of the resonance peak remained basically unchanged. The wavelength shift was calculated by extracting the wavelength positions of the resonance peaks at different concentrations and comparing them with the wavelength positions of the resonance peaks in PBS solution. This difference was then used as a function curve of concentration, as shown in Figure (a). Figure 6As shown in (b), when the concentration of IFN-γ increases from 10 pM to 1 nM, the wavelength shift increases relatively slowly, only from 0.04 nm to 0.37 nm. However, when the concentration increases from 1 nM to 1 μM, the wavelength shift increases rapidly to 3.01 nm. Fitting the wavelength shift results, the maximum wavelength shift at saturated adsorption is 3.98 nm, the equilibrium dissociation constant is 98.43 nM, and the Hill coefficient is 0.47. The sensor's detection limit is based on 3... Based on the principle of calculating the wavelength shift ∆LOD corresponding to the detection limit concentration, we get 0.2176 nm, and the detection limit LOD is calculated to be 1.282 nM.

[0078] Example 2:

[0079] The fabrication experiment of a gold nanopore array metasurface biosensor includes the following steps:

[0080] Step 1: Spin-coat the release agent onto the nanopore array template and dry it.

[0081] Step 2: Evaporate 2nm copper and 70nm gold onto the template surface.

[0082] Step 3: Demold in water, retrieve gold nanofilm using quartz glass, and then vacuum dry at room temperature for 1 hour.

[0083] Step 4: Remove residual impurities from the dried gold nanofilm by irradiation with ultraviolet light, and then spin-coat photoresist onto the cleaned gold surface.

[0084] Step 5: Use an ultraviolet lithography machine to expose the gold film through the prepared photomask. The photomask structure is as follows: Figure 8 As shown.

[0085] Step 4: Immerse the dried gold nanofilm in a 1mM aqueous solution of 4-mercaptobenzoic acid and let it stand in a sealed container at 4°C for 12 hours.

[0086] Step 5: Remove the membrane and rinse it with deionized water. After drying, add equal amounts of 2mM 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride solution and 5mM N-hydroxysuccinimide solution to the membrane surface and let it stand for 1 hour to activate the carboxyl groups.

[0087] Step 6: After activating the carboxyl group, rinse with deionized water and then add IL-6 and CRP nucleic acid aptamer solutions to different sensor areas to soak the gold film. Seal and let stand in the dark for 12 hours.

[0088] Step 7: After aptamer modification, rinse with deionized water and passivate the carboxyl groups that have not yet bound to the aptamer with ethanolamine solution to complete the sensor fabrication. Figure 9 As shown.

[0089] Sensor structure and principle as follows Figure 7 As shown in the figure. During the preparation process, transmission spectroscopy was performed on the surface of the gold nanofilm to ensure the success of each modification step. The results are as follows. Figure 8 As shown in the figure, the transmission spectroscopy results from the three stages reveal that after modification with 4-mercaptobenzoic acid and the aptamer, the resonance peaks all exhibited a "red shift" compared to their previous positions, indicating a shift towards longer wavelengths. This suggests that the core layer thickness on the surface of the gold nanopore array has changed, meaning that both 4-mercaptobenzoic acid and the aptamer have been successfully modified onto the surface of the gold nanopore array. The gold nanopore array metasurface biosensor has been successfully fabricated.

[0090] The interleukin-6 concentration detection experiment includes the following steps:

[0091] Step 1: Dissolve IL-6 dry powder in PBS buffer according to the specified ratio to prepare a 1 nM standard solution.

[0092] Step 2: Dispense the prepared standard solution into centrifuge tubes and freeze it at -20°C.

[0093] Step 3: Thaw one portion of the protein standard solution and dilute it with PBS buffer to a 100 pM solution. Then, prepare 10 solutions according to a certain concentration gradient. -2 pM to 10 2 pM test solution.

[0094] Step 4: Use a pipette to add 30 μL of the test solution to the sensor, let it stand for 10 min to react, and after the reaction is complete, rinse with plenty of deionized water and blow dry with nitrogen.

[0095] Step 5: Clamp the sensor in the optical path and measure the transmission spectrum.

[0096] The results are as follows Figure 9 As shown in (a), a "redshift" phenomenon was observed in the resonance peak as the concentration of IL-6 gradually increased. Specifically, the resonance peak of the TM0 mode shifted towards longer wavelengths with increasing concentration, while the quality factor of the resonance peak remained essentially unchanged. To more intuitively and accurately observe the change in resonance peak wavelength, the resonance wavelengths corresponding to different concentrations were extracted, and the difference between these wavelengths and the resonance wavelength of the pure PBS solution was calculated to obtain the wavelength shift. This shift was then presented as a function curve of concentration, as shown in Figure (a). Figure 9 As shown in (b), when the concentration of IL-6 increases from 0 to 100 pM, the resonant wavelength shift reaches 3.1829 nm. Fitting the wavelength shift results, the maximum wavelength shift at saturated adsorption is 3.07651 nm, the equilibrium dissociation constant is 0.19366 pM, and the Hill coefficient is 0.5417.

[0097] According to 3 The calculated limit of detection (LOD) is 56.11 fM. The normal range of IL-6 concentration in human blood is 50-500 fM, which can rise to about 5 pM after infection or inflammation. The detection limit of the biosensor is within the normal concentration range of the human body, and the IL-6 concentration in the human body during infection does not exceed the saturation concentration of the sensor, which can meet the basic detection requirements.

[0098] The C-reactive protein concentration detection experiment includes the following steps:

[0099] Step 1: Dissolve CRP powder in PBS buffer according to the specified ratio to prepare a 1 nM standard solution.

[0100] Step 2: Dispense the prepared standard solution into centrifuge tubes and freeze it at -20°C.

[0101] Step 3: Thaw one portion of the protein standard solution and dilute it with PBS buffer to a 100 pM solution. Prepare 0, 10, and 20 pM solutions in ascending order of concentration. -4 μM, 10 -3 μM, 10 -2 μM, 10 -1 Six concentration gradients at μM and 1μM.

[0102] Step 4: Use a pipette to add 30 μL of the test solution to the sensor, let it stand for 10 min to react, and after the reaction is complete, rinse with plenty of deionized water and blow dry with nitrogen.

[0103] Step 5: Clamp the sensor in the optical path and measure the transmission spectrum.

[0104] Spectroscopic measurement results of solutions at different concentrations are as follows Figure 10 As shown in (a), with the increase of CRP concentration, the resonance peak of the TM0 mode also exhibited a "redshift" phenomenon. The resonance peak wavelength shifted to a longer wavelength direction, and the quality factor of the sensor did not change significantly. The wavelength shift was calculated by extracting the resonance peak wavelength positions at different concentrations and comparing them with the resonance peak wavelength positions of the PBS solution. This difference was then used as a function curve of concentration, as shown in (a). Figure 10 As shown in (b), when the CRP concentration increases from 0 to 1 μM, the resonant wavelength shift reaches 2.49975 nm. Fitting the wavelength shift results, the maximum wavelength shift at saturated adsorption is 2.97 nm, the equilibrium dissociation constant is 0.00576 μM, and the Hill coefficient is 0.31188.

[0105] The sensor's detection limit is based on 3 Based on the principle of calculating the wavelength shift ∆LOD corresponding to the detection limit concentration, we arrive at a detection limit LOD of 0.37365 nm, resulting in a detection limit LOD of 11.1 pM. The normal concentration range of CRP in human blood is 0-42 nM, but it can increase by 1000-fold during the acute phase of infection or inflammation. The detection limit of the biosensor meets the detection requirements.

[0106] Example 3:

[0107] A gold nanopore array surface lattice resonance metasurface biosensor was used to detect glucose concentration by light intensity method. The experimental steps are as follows:

[0108] The sensor manufacturing process is as follows Figure 11 As shown:

[0109] Step 1: Fabrication of a gold nanoporous array metasurface;

[0110] Step 2: Transfer graphene onto the metasurface;

[0111] Step 3: Place the metasurface with transferred graphene in a pyrene-1-boric acid (PBA) solution and let it stand;

[0112] Step 4: Remove the sample, rinse it sequentially with N,N-dimethylformamide (DMF) and anhydrous ethanol, and dry it with nitrogen gas;

[0113] Step 5: Add the test solution to the sample, let it stand for 10 minutes, rinse with deionized water, and then dry with nitrogen gas;

[0114] Step 6: Clamp the reacted sample in the optical path, measure the transmitted light intensity, and detect the optical path as follows. Figure 12 As shown, the illumination source is a 785nm laser.

[0115] Test results as follows Figure 13 As shown, the transmitted light intensity decreases continuously with the increase of glucose concentration in the test solution. The relationship between transmitted light intensity and glucose concentration can be fitted by the Hill-Langmuir equation, and the fitting result is as follows.

[0116]

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principle of the present invention. For example, the material and parameters of the metasurface can be changed, the material and thickness parameters of the metasurface core layer can be changed, the material and parameters of the modification layer can be changed, the type of modification can be changed, and the processing and preparation process of the metasurface can be changed. These improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A biosensing method based on a guided-mode lattice resonance metasurface, characterized in that, Includes the following steps: Step 1: Provide a mode-guided lattice resonance metasurface and a light source; A guided-mode lattice resonance metasurface is provided, comprising a substrate, a biomodification layer, and a nanostructure array. The substrate, the biomodification layer, and the surface working medium constitute a planar waveguide, the biomodification layer serving as the core layer of the planar waveguide, and the nanostructure array being a periodic nanostructure array. The surface working medium is air, an aqueous solution, or other biocompatible liquid capable of carrying target biomolecules without destroying their activity. A light source is provided to irradiate the metasurface. Step 2: Achieve specific binding of biomolecules; The metasurface is immersed in a solution containing target biomolecules or exposed to an air environment containing target molecules, so that the bioprobe molecules specifically bind to the target biomolecules, resulting in a change in the thickness of the biomodification layer of the metasurface, that is, a change in the thickness of the core layer. Step 3: Detect the optical signal and determine the concentration of the target molecule; The wavelength shift of the guided mode lattice resonance peak of the metasurface is measured, and the concentration of the target molecules is determined based on the relationship between the wavelength shift and the target molecule concentration; or the change in the intensity of transmitted or reflected light in a fixed band near the resonance peak is measured, and the concentration of the target molecules is determined based on the relationship between the change in light intensity and the target molecule concentration; the above method of measuring optical signals and determining the target molecule concentration is a detection method. The light source is a broadband light source, and the detection method is used to measure the wavelength change of the guided mode lattice resonance peak of the metasurface; The guided mode lattice resonance metasurface contains multiple partitions, and the biological probe molecules modified on the metasurfaces of different partitions may be the same or different. The wavelength variation of the resonance peak of the guided mode lattice resonance metasurface satisfies the Hill-Langmuir equation with respect to the concentration of the target biomolecules. The change in the intensity of transmitted or reflected light at the fixed wavelength band satisfies the Hill-Langmuir equation with respect to the concentration of the target biomolecule.

2. The biosensing method based on a guided-mode lattice resonance metasurface according to claim 1, characterized in that: The substrate has a single or multi-layer structure and is made of solid material.

3. The biosensing method based on a guided-mode lattice resonance metasurface according to claim 1, characterized in that: The biomodified layer includes bioprobe molecules and a connecting material for connecting the bioprobe molecules to the substrate. The bioprobe molecules include, but are not limited to, nucleic acid aptamers, antibodies, or small molecule ligands.

4. The biosensing method based on a guided-mode lattice resonance metasurface according to claim 1, characterized in that: The nanostructure array is a nanopore array, a nanoparticle array, or a combination thereof.

5. The biosensing method based on a guided-mode lattice resonance metasurface according to claim 1, characterized in that: The light source is a single-wavelength light source, and the detection method is used to measure the changes in transmitted or reflected light intensity in different partitions of the metasurface.

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