A biochemical detection chip and its preparation method

Abstract

This invention relates to the field of biochemical detection elements, and discloses a biochemical detection chip and its fabrication method. The biochemical detection chip includes a substrate layer and a particle array disposed on the substrate layer. The particle array is composed of multiple metal nanoparticles arranged according to a preset arrangement rule. The multiple metal nanoparticles have the same shape, and the diameter and height of each metal nanoparticle are both preset lengths and preset heights. Thus, the obtained biochemical detection chip has the advantages of high detection sensitivity, small size, and easy integration.

Description

Technical Field

[0001] This invention relates to the field of biochemical detection elements, and in particular to a biochemical detection chip and its preparation method. Background Technology

[0002] Utilizing biochemical sensors to detect and analyze the types and concentrations of chemical and biomolecules in samples has wide applications in life and health fields such as biomedicine, biosafety, environmental monitoring, and public health. Optical detection is one of the important methods of biochemical detection. Compared with traditional biochemical detection methods, spectroscopic methods do not require sample preparation and have advantages such as speed, non-invasiveness, high efficiency, and dynamism, making them suitable for rapid on-site detection and continuous real-time online analysis. Plasmon nanostructures, where free electrons generate collective oscillations under light excitation at corresponding resonance wavelengths, localize the light field to a nanoscale space much smaller than the wavelength, overcoming the diffraction limit, and have very broad application prospects in the field of miniaturized optical devices. Plasmon structures have a nanoscale localized light field enhancement effect. Through the interaction between the enhanced electromagnetic field around the nanostructure and the target molecule, changes in interfacial refractive index with substance concentration can be sensitively detected. This method features high sensitivity, low background interference, rapid response, and no need for sample labeling, making it of significant application value in highly sensitive label-free sensing detection.

[0003] Currently, plasmon-based detection devices are mainly divided into two categories: surface plasmon polariton (SPP) devices and localized surface plasmon (LSP) devices. SPP detection devices excite plasmons on the surface of metal films using a prism system, exhibiting a bulk effect that reduces selectivity. Furthermore, these devices are bulky and difficult to integrate. In contrast, LSP detection devices are simpler and easier to miniaturize and integrate. However, their wider peak width leads to relatively lower sensitivity. Moreover, current plasmon-based detection devices suffer from low selectivity, making simultaneous detection of multiple analytes difficult and resulting in low detection efficiency. Summary of the Invention

[0004] The present invention aims to solve the technical problems of large size, difficulty in integration, and low detection sensitivity of biochemical detection devices.

[0005] To address the aforementioned technical problems, this application discloses a biochemical detection chip, comprising a substrate layer and a particle array disposed on the substrate layer;

[0006] The particle array is composed of multiple metal nanoparticles arranged according to a preset arrangement rule;

[0007] Multiple metal nanoparticles have the same shape; the diameter of multiple metal nanoparticles is a preset length, and the height of multiple metal nanoparticles is a preset height.

[0008] Furthermore, the surfaces of multiple metal nanoparticles are modified with biochemical molecules.

[0009] Furthermore, the substrate material includes silicon dioxide.

[0010] This application also discloses a method for preparing a biochemical detection chip, the method comprising:

[0011] Determine the preset arrangement rules of the particle array and the preset shape, preset length, and preset height of multiple metal nanoparticles in the particle array; the preset length is the diameter of multiple metal nanoparticles; the preset height is the height of multiple metal nanoparticles.

[0012] A photoresist array is formed on a silicon wafer based on a preset arrangement rule and preset length.

[0013] Metal thin films are formed on silicon wafers using photoresist arrays;

[0014] Transferring a thin metal film from a silicon wafer to a substrate layer;

[0015] An initial detection array is obtained by forming a particle array on a substrate layer based on a metal thin film.

[0016] The initial detection array was divided into slices to obtain multiple biochemical detection chips.

[0017] Furthermore, the method for determining the preset arrangement rules of the particle array and the preset length and preset height of multiple metal nanoparticles in the particle array is the finite-difference time-domain method.

[0018] Furthermore, a photoresist array is formed on the silicon wafer based on a preset arrangement rule and preset length, including:

[0019] Design a photoresist array mold based on preset arrangement rules and preset length;

[0020] A photoresist array is formed by imprinting it onto a silicon wafer using a photoresist array mold.

[0021] Furthermore, forming a metal thin film on a silicon wafer based on a photoresist array includes:

[0022] Depositing a sacrificial layer on a silicon wafer based on a photoresist array;

[0023] Deposit a thin metal film on the sacrificial layer.

[0024] Further, transferring the metal thin film from the silicon wafer to the substrate layer includes:

[0025] The sacrificial layer is etched away to obtain a metal film separated from the silicon wafer;

[0026] A thin metal film, separated from the silicon wafer, is transferred onto a substrate.

[0027] Furthermore, after obtaining the initial detection array by forming a particle array on the substrate based on a metal thin film, the process also includes:

[0028] The initial detection array is annealed.

[0029] Furthermore, after annealing the initial detection array, the process also includes:

[0030] Biochemical molecules are modified in multiple metal nanoparticles of a particle array.

[0031] By adopting the above technical solution, the biochemical detection chip provided in this application has the following beneficial effects:

[0032] The biochemical detection chip disclosed in this application includes a substrate layer and a particle array disposed on the substrate layer. The particle array is composed of multiple metal nanoparticles arranged according to a preset arrangement rule. The multiple metal nanoparticles have the same shape. The diameter of the multiple metal nanoparticles is a preset length, and the height of the multiple metal nanoparticles is a preset height. Thus, the resulting biochemical detection chip has the advantages of high detection sensitivity, small size, and easy integration. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a biochemical detection chip provided in an embodiment of this application;

[0035] Figure 2 This is a schematic flowchart of a method for preparing a biochemical detection chip according to an embodiment of this application;

[0036] Figure 3 This is a schematic flowchart of a method for preparing a biochemical detection chip according to an embodiment of this application;

[0037] Figure 4 This is a schematic flowchart of a method for preparing a biochemical detection chip according to an embodiment of this application;

[0038] Figure 5 This is a schematic flowchart of a method for preparing a biochemical detection chip according to an embodiment of this application;

[0039] Figure 6 This is a schematic flowchart of a method for preparing a biochemical detection chip according to an embodiment of this application;

[0040] Figure 7 This is a schematic flowchart of a method for preparing a biochemical detection chip according to an embodiment of this application;

[0041] Figure 8 This is a schematic flowchart of a biochemical detection chip fabrication method provided in an embodiment of this application.

[0042] The following is supplementary explanation of the attached figures:

[0043] 1-Base layer; 100-Silicon wafer; 110-Photoresist array; 120-Metal thin film; 121-Sacrificial layer; 2-Particle array; 21-Metal nanoparticles; 200-Photoresist array mold; 3-Initial detection array; 4-Biochemical detection chip. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0045] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0046] Figure 1 This application provides a schematic diagram of the structure of a biochemical detection chip according to an embodiment of the present application. Figure 1 As shown, the biochemical detection chip includes a substrate layer 1 and a particle array 2 disposed on the substrate layer 1. The particle array 2 is composed of multiple metal nanoparticles 21 arranged according to a preset arrangement rule.

[0047] The multiple metal nanoparticles 21 in the particle array 2 have the same shape, and their diameter and height are also equal. Specifically, the diameter of the multiple metal nanoparticles 21 is a preset length, and the height of the multiple metal nanoparticles 21 is a preset height.

[0048] The localized surface plasmons excited by the metal nanoparticles 21 in the gold particle array 2 are coupled with the Rayleigh anomalous diffraction light of the particle array 2 to form surface lattice resonance. This gives the biochemical detection chip of this application the characteristics of large near-field enhancement and low radiation loss, thereby reducing the plasmon resonance peak width and improving the detection sensitivity.

[0049] As an optional implementation, through simulation, an array structure that can guarantee the detection accuracy and range of the biochemical detection chip is selected from multiple results. Based on the array structure, the preset arrangement rules of the particle array 2 and the shape, diameter and height of the metal nanoparticles 21 therein are determined.

[0050] As an alternative implementation, the surface of the plurality of metal nanoparticles 21 may be modified with biochemical molecules.

[0051] As an optional implementation method, the modified biochemical molecule can be determined according to the actual needs of the detection. The biochemical molecule can be a macromolecular structure such as DNA or protein, or a small molecule structure such as dopamine or acetylcholine.

[0052] By modifying the surface of metal nanoparticles 21 with biochemical molecules, only specific detectable molecules that are consistent with the modified biochemical molecules can change the refractive index around the metal nanoparticles 21, thereby improving the selectivity of detection.

[0053] As an alternative implementation, the material of the substrate 1 includes silicon dioxide.

[0054] As an alternative implementation, the material of the substrate 1 can also be other high-temperature resistant transparent materials, such as sapphire.

[0055] As an alternative implementation, the material of the particle array 2 can be selected from a variety of options, and the material that meets the detection requirements can be determined based on simulation.

[0056] on the other hand, Figures 2-8 This application provides a schematic flowchart of a method for fabricating a biochemical detection chip, as illustrated in an embodiment. Figure 2 As shown, the preparation method includes:

[0057] S201: Determine the preset arrangement rules of the particle array 2 and the preset shape, preset length and preset height of the multiple metal nanoparticles 21 in the particle array 2.

[0058] In this embodiment, the preset length is the diameter of the plurality of metal nanoparticles 21, and the preset height is the height of the plurality of metal nanoparticles 21.

[0059] In this embodiment, the array structure of the particle array 2 is designed by finite difference time-domain simulation, the optimal array structure that can meet the detection requirements is selected, and this optimal array structure is determined as the array structure of the particle array 2. The preset arrangement rules of the particle array 2 and the preset shape, preset length and preset height of the metal nanoparticles 21 are determined at one time.

[0060] As an alternative implementation, the optimal array structure is determined by calculating the far-field and near-field optical responses of the plasmon structure under illumination in a simulated array structure. Based on the resonance spectrum of the array structure in the far-field optical response, parameters such as the position, full width at half maximum (FWHM), and intensity of the resonance peaks are obtained. Based on the range and intensity of the plasmon hotspots in the near-field optical response, the size and density of the biochemical molecules modified on the surface of the metal nanoparticles 21 are determined.

[0061] As an optional implementation, the array structure of the particle array 2 may include parameters such as the material, shape, size, arrangement rules, internal structure and surface modification of the metal nanoparticles 21.

[0062] S203: Form a photoresist array 110 on the silicon wafer 100 based on a preset arrangement rule and a preset length.

[0063] In this embodiment, a photoresist array mold 200 is designed based on a preset arrangement rule and a preset length, and then a photoresist array 110 is formed by imprinting the photoresist array mold 200 onto a silicon wafer 100. The formed photoresist array 110 has multiple protrusions, which are consistent with the arrangement of metal nanoparticles 21 in the pre-designed particle array 2.

[0064] As an alternative implementation, the photoresist array 110 can be formed using a polydimethylsiloxane (PDMS) nanoprinting method.

[0065] S205: A metal thin film 120 is formed on a silicon wafer 100 based on a photoresist array 110.

[0066] In this embodiment, a sacrificial layer 121 is first deposited on the area of ​​the silicon wafer 100 not covered by the photoresist array 110 using a metal deposition method, and then a metal thin film 120 is deposited on the sacrificial layer 121. The positions of the gaps in the formed metal thin film 120 correspond one-to-one with the protrusions of the photoresist array 110.

[0067] As an optional implementation, the thickness of the metal film 120 can be used to further adjust the size of the voids in the metal film 120. That is, during the deposition process, the deposited metal will gradually squeeze the voids, causing the voids to gradually decrease. The thicker the metal film 120 is deposited, the smaller the voids in the metal film. Thus, by changing the thickness of the deposited metal film 120, the voids in the metal film 120 can be adjusted, and the size of the metal nanoparticles 21 in the formed particle array 2 can be ultimately adjusted.

[0068] As an alternative implementation, the material of the metal film 120 can be a metal such as gold, copper, silver, or aluminum.

[0069] As an alternative implementation, the material of the sacrificial layer 121 can be other metals such as chromium and titanium.

[0070] S207: Transfer the metal thin film 120 from the silicon wafer 100 to the substrate layer 1.

[0071] In this embodiment, the sacrificial layer 121 is removed in a wet etching solution, thereby separating the metal film 120 from the silicon wafer 100. The metal film 120 separated from the silicon wafer 100 is transferred to water, allowing it to float on the water surface. Then, the substrate layer 1 is used to scoop up the metal film 120, thereby transferring the metal film 120 onto the substrate layer 1.

[0072] As an alternative implementation, a chromium etching solution can be used as the etching solution for the sacrificial layer 121 formed of chromium.

[0073] The resulting metal film 120 is not deposited on the substrate 1. It can be directly separated from the substrate 1 after use, which is convenient for operation and can be reused to a certain extent, thereby reducing costs.

[0074] S209: Based on the metal thin film 120, a particle array 2 is formed on the substrate layer 1 to obtain the initial detection array 3.

[0075] In this embodiment, the metal thin film 120 acts as a physical deposition mask on the substrate layer 1. Metal deposition is performed on the substrate layer 1, and metal nanoparticles 21 of the particle array 2 are formed at the positions of the gaps in the metal thin film 120. The metal thin film 120 is then peeled off to obtain the initial detection array 3. The positions of the metal nanoparticles 21 correspond one-to-one with the positions of the protrusions of the photoresist array 110, and the positions of the protrusions of the photoresist array 110 are consistent with the pre-designed arrangement of the metal nanoparticles 21, so that the final metal nanoparticles 21 are arranged according to the pre-designed arrangement.

[0076] As an optional implementation, after obtaining the initial detection array 3, the initial detection array 3 is processed by annealing to optimize the crystal structure and surface shape inside the metal nanoparticles 21, thereby obtaining a high-quality particle array 2 and a high-quality surface lattice resonance.

[0077] As an alternative implementation, the surface of the annealed metal nanoparticles 21 is modified to detect the required biochemical molecules.

[0078] As an alternative implementation method, the biochemical molecules can be macromolecules such as DNA and proteins, or small molecules such as dopamine and acetylcholine.

[0079] S211: Divide the initial detection array 3 into multiple biochemical detection chips 4.

[0080] In this embodiment, the initial detection array 3 may include multiple biochemical detection chips 4. The above method enables the formation of a large-area initial detection array 3 in a single step, and the initial detection array 3 can be diced to obtain multiple biochemical detection chips 4. This allows for the preparation of multiple biochemical detection chips 4 in a single process, reducing preparation steps, simplifying the preparation method, and lowering costs.

[0081] In the prior art, there are generally two methods for preparing particle array 2:

[0082] (1) Single-crystal nanoparticles are prepared by chemical synthesis, but their array arrangement is difficult to control;

[0083] (2) Regular arrays are prepared by micro-nano processing methods such as photolithography, but the particles formed by evaporation / electroplating are polycrystalline and irregular in shape at the nanoscale. As a result, the surface lattice resonance and the detection theoretical lattice resonance half-width of the particle array 2 are generally greater than 10 nm, which cannot meet the requirements of high detection accuracy.

[0084] The biochemical detection chip fabrication method provided in this application utilizes a nano-stamping method to form a photoresist array 110 on a silicon wafer 100, deposits a metal thin film 120 on the silicon wafer 100, transfers the metal thin film 120 to a substrate layer 1 through etching, and finally forms metal nanoparticles 21 on the substrate layer 1 by metal deposition and metal stripping 120, arranged according to a preset arrangement rule and meeting shape and size requirements, thereby obtaining a particle array 2 that meets the requirements of high detection accuracy.

[0085] The following example, using a square silver nanoparticle array biochemical detection chip with a period of 600 nm, further illustrates the preparation method of the biochemical detection chip provided in this application.

[0086] First, the array structure of particle array 2 was designed by simulation using the finite-difference time-domain method. The array structure of the particles in array 2 was determined to be semi-ellipsoidal silver nanoparticles with a period of 450-600nm, a diameter of 80-120nm, and a height of 80-100nm.

[0087] Based on the array structure of particle array 2, the photoresist array mold 200 is designed with a period of 450-600nm and a diameter of 200-250nm. A polydimethylsiloxane (PDMS) via array mold is used. A photoresist array 110 with the same period and diameter as the photoresist array mold 200 is formed by imprinting the photoresist array mold 200 onto the silicon wafer 100.

[0088] A sacrificial layer 121 is formed on a silicon wafer 100 by metal deposition. The sacrificial layer 121 is made of chromium, with a period of 450-600 nm, a diameter of 120-150 nm, and a thickness of 5-100 nm. A metal thin film 120 is deposited on the sacrificial layer 121. The metal thin film 120 is made of gold, with a period of 450-600 nm, a diameter of 120-150 nm, and a thickness of 80-300 nm.

[0089] The sacrificial layer 121 is removed by etching in a wet etching solution. The metal film 120 is then transferred to water and floats on the water surface. At this point, the metal film 120 on the water surface is retrieved by the substrate layer 1 and transferred to the substrate layer 1.

[0090] Silver of 80-150 nm is deposited on substrate 1, and metal film 120 is peeled off to form particle array 2 on substrate 1. Particle array 2 is a silver particle array with a period of 450-600 nm, a diameter of 80-150 nm, and a height of 80-150 nm, thereby obtaining initial detection array 3.

[0091] The prepared initial detection array 3 was annealed in a tube furnace at 600-900°C for 20-60 minutes to optimize the internal crystal structure and surface shape of the particle array 2.

[0092] Taking DNA detection as an example, the initial detection array 3 is placed in a solution to modify single-stranded DNA molecules on the metal nanoparticles 21 of the particle array 2, thereby achieving selective detection of the target DNA.

[0093] Finally, the initial detection array 3 was divided into 1x1cm pieces. 2 From a single chip, multiple biochemical detection chips capable of selectively detecting DNA are obtained.

[0094] This application discloses a biochemical detection chip and its fabrication method. The biochemical detection chip includes a substrate layer and a particle array disposed on the substrate layer. The particle array is composed of multiple metal nanoparticles arranged according to a preset arrangement rule. The multiple metal nanoparticles have the same shape, and the diameter and height of the multiple metal nanoparticles are all preset lengths and preset heights. Thus, the obtained biochemical detection chip has the advantages of high detection sensitivity, small size, and easy integration.

[0095] The above description is only an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A biochemical detection chip, characterized in that, It includes a base layer (1) and a particle array (2) disposed on the base layer (1); The particle array (2) is composed of multiple metal nanoparticles (21) arranged according to a preset arrangement rule; The plurality of metal nanoparticles (21) have the same shape so that the local surface plasmons excited by the metal nanoparticles (21) are coupled with the Rayleigh anomalous diffraction light of the particle array (2) to form surface lattice resonance; the diameter of the plurality of metal nanoparticles (21) is a preset length and the height of the plurality of metal nanoparticles (21) is a preset height. The surfaces of the plurality of metal nanoparticles (21) are modified with biochemical molecules; The material of the metal nanoparticles, the shape of the metal nanoparticles, the preset height, the preset length, the preset arrangement rule, the internal structure of the metal nanoparticles, the size of the biochemical molecules, and the density of the biochemical molecules constitute the array structure of the particle array (2); the array structure of the particle array (2) is designed based on the finite-difference time-domain method; the size of the biochemical molecules and the density of the biochemical molecules are determined with the assistance of the range and intensity of the plasmon hotspots in the near-field optical response of plasmons under illumination.

2. The biochemical detection chip according to claim 1, characterized in that, The material of the substrate layer (1) includes silicon dioxide.

3. A method for preparing a biochemical detection chip, characterized in that, The method includes: Determine the preset arrangement rules of the particle array (2) and the preset shape, preset length and preset height of the multiple metal nanoparticles (21) in the particle array (2); the preset length is the diameter of the multiple metal nanoparticles (21); the preset height is the height of the multiple metal nanoparticles (21); A photoresist array (110) is formed on a silicon wafer (100) based on the preset arrangement rules and the preset length. A metal thin film (120) is formed on the silicon wafer (100) based on the photoresist array (110). The metal thin film (120) is transferred from the silicon wafer (100) to the substrate layer (1). The particle array (2) is formed on the substrate layer (1) based on the metal thin film (120) so that the local surface plasmons excited by the metal nanoparticles (21) are coupled with the Rayleigh anomalous diffraction light of the particle array (2) to form surface lattice resonance; and biochemical molecules are modified in the plurality of metal nanoparticles (21) of the particle array (2) to obtain an initial detection array (3); wherein, the material of the metal nanoparticles, the shape of the metal nanoparticles, the preset height, the preset length, the preset arrangement rule, the internal structure of the metal nanoparticles, the size of the biochemical molecules and the density of the biochemical molecules constitute the array structure of the particle array (2); the array structure of the particle array (2) is designed based on the finite difference time-domain simulation method; the size of the biochemical molecules and the density of the biochemical molecules are determined with the assistance of the range and intensity of the plasmon hotspots in the near-field optical response of the plasmons under illumination; The initial detection array (3) is diced to obtain multiple biochemical detection chips (4).

4. The method for preparing a biochemical detection chip according to claim 3, characterized in that, The process of forming a photoresist array (110) on a silicon wafer (100) based on the preset arrangement rules and the preset length includes: The photoresist array mold (200) is designed based on the preset arrangement rules and the preset length. The photoresist array (110) is formed by imprinting the photoresist array mold (200) onto the silicon wafer (100).

5. The method for preparing a biochemical detection chip according to claim 3, characterized in that, The formation of a metal thin film (120) on the silicon wafer (100) based on the photoresist array (110) includes: A sacrificial layer (121) is deposited on the silicon wafer (100) based on the photoresist array (110). A metal thin film (120) is deposited on the sacrificial layer (121).

6. The method for preparing a biochemical detection chip according to claim 5, characterized in that, The step of transferring the metal thin film (120) from the silicon wafer (100) to the substrate layer (1) includes: The sacrificial layer (121) is etched away to obtain a metal film (120) separated from the silicon wafer (100). The metal thin film (120) separated from the silicon wafer (100) is transferred onto the substrate layer (1).

7. The method for preparing a biochemical detection chip according to claim 3, characterized in that, After the initial detection array (3) is obtained by forming the particle array (2) on the substrate layer (1) based on the metal thin film (120), the method further includes: The initial detection array (3) is annealed.

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