A flexible cobalt ferrite film biosensor and a preparation method thereof
By combining a flexible cobalt ferrite film with PDMS and doping it with AuNPS gold nanolayers, the problems of complex and high cost in the fabrication of existing magnetoelastic sensors have been solved, enabling low-cost, high-flexibility, and highly biocompatible multi-antigen detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANXI SIX DIMENSIONAL ARTIFICIAL INTELLIGENCE BIOMEDICAL RES INST
- Filing Date
- 2022-12-01
- Publication Date
- 2026-06-23
AI Technical Summary
Existing magnetoelastic biosensors use rigid metal alloys as substrates, which are complex, expensive and difficult to degrade, have limited detection methods, are time-consuming, have poor anti-interference capabilities, and are costly.
A flexible biosensor was constructed by combining a flexible cobalt ferrite thin film with PDMS, doping the surface with AuNPS gold nanoparticles, and modifying antibodies through self-assembly. This enabled the detection of multiple antigens by utilizing the combination of cobalt ferrite nanoparticles and PDMS, as well as the electromagnetic properties and biocompatibility of the AuNPS gold nanoparticles.
This has resulted in a low-cost, highly flexible, and biocompatible biosensor that can detect different antigens based on modified antibodies, expanding its application range, simplifying the preparation process, and improving detection efficiency.
Smart Images
Figure CN115656520B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of biosensor technology, specifically a flexible cobalt ferrite thin film biosensor and its preparation method. Background Technology
[0002] Currently, most sensors are made using rigid materials such as metal alloys as substrates. However, the fabrication of these substrates requires many expensive and large-scale instruments and complex manufacturing processes, making them difficult to produce, and they are not biodegradable. The application of rigid materials is somewhat limited, while flexible materials can avoid this problem, as they have excellent flexibility and tensile strength.
[0003] In recent years, flexible materials have developed rapidly in the international research field. Flexible films refer to films made of flexible materials that can be stretched and extended according to needs, exhibiting strong plasticity. Flexible films can be freely transformed and designed into special and varied structures according to requirements, and can be applied to miniature portable biosensors.
[0004] Magnetoelastic biosensors, as a novel sensing device, use rigid metal alloys such as iron-nickel alloys and nickel-cobalt alloys as substrates. However, the fabrication process of these magnetoelastic sensors requires expensive, large-scale instruments and suffers from problems such as non-renewability, poor biodegradability, poor flexibility, high cost, and complex fabrication processes. Current magnetoelastic sensors typically use vector network analyzers to measure the resonant frequency change of the magnetostrictive material before and after detecting the analyte for quantitative detection. This method is singular, the equipment is expensive, time-consuming, the testing steps are complex, and the anti-interference capability is poor. Even minor external vibrations have a significant impact on measurement accuracy and system stability. Summary of the Invention
[0005] This invention overcomes the shortcomings of the prior art and proposes a flexible cobalt ferrite thin film biosensor and its preparation method.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution.
[0007] A flexible cobalt ferrite thin film biosensor includes a flexible cobalt ferrite / PDMS thin film; the surface of the flexible cobalt ferrite / PDMS thin film is doped with an AuNPS nano-gold layer; the AuNPS nano-gold layer is modified with an antibody;
[0008] The flexible cobalt ferrite / PDMS film is obtained by adding cobalt ferrite nanoparticles to the A-type adhesive of PDMS to obtain a cobalt ferrite nanogel fluid, and then mixing the cobalt ferrite nanogel fluid with the B-type adhesive of PDMS film; the mass ratio of cobalt ferrite nanoparticles to the A-type adhesive of PDMS is 1:4-6.
[0009] Preferably, the mass ratio of cobalt ferrite nanoparticles to PDMS A-type adhesive is 1:5.
[0010] Preferably, the mass ratio of cobalt ferrite nanogel fluid to PDMS film B adhesive is 10-13:1.
[0011] A method for preparing a flexible cobalt ferrite thin film biosensor includes the following steps:
[0012] 1) Preparation of flexible cobalt ferrite / PDMS film: Cobalt ferrite nanoparticles were dispersed in PDMS A-resin to obtain a uniform cobalt ferrite nanogel fluid; the mass ratio of cobalt ferrite nanoparticles to PDMS A-resin was 1:4-6; the cobalt ferrite nanogel fluid was mixed with PDMS film B-resin to obtain a flexible cobalt ferrite / PDMS film.
[0013] 2) Reduction of AuNPs on the film surface: The flexible cobalt ferrite / PDMS film is immersed in chloroauric acid solution and reacted in the dark for 16-20 hours; AuNPS nano-gold layer is doped on the surface of the flexible cobalt ferrite / PDMS film.
[0014] 3) Antibody modification: A flexible cobalt ferrite / PDMS film doped with AuNPS nano-gold layer is immersed in a mercaptoethylamine solution to form a self-assembled membrane. Then, the self-assembled membrane is immersed in an activated antibody solution to allow the antibody to bind uniformly to the surface of the self-assembled membrane.
[0015] Preferably, the mass ratio of cobalt ferrite nanoparticles to PDMS A-type adhesive is 1:5.
[0016] Preferably, the flexible cobalt ferrite / PDMS film doped with AuNPS nano-gold layer is ultrasonically cleaned and air-dried before being immersed in chloroauric acid solution.
[0017] Preferably, the antibody solution is diluted and activated: the antibody solution is diluted with PBS solution to obtain an appropriate antibody concentration; at room temperature, the antibody solution is mixed and shaken with a solution containing 4 mg / mL EDC and 4 mg / mL NHS to activate the carboxyl groups in the antibody into NHS esters, so that the antibody binds to the amino groups on the surface of the self-assembled layer more efficiently.
[0018] Preferably, the antibody-modified self-assembled membrane is immersed in PBS solution; the PBS solution containing the chip is placed in an environment of 37°C and left to stand for 0.5 h to remove the antibodies physically adsorbed on the surface.
[0019] The beneficial effects of this invention compared to the prior art are as follows:
[0020] 1. This invention is the first to utilize a combination of cobalt ferrite nanoparticles and PDMS, with AuNPS nanoparticles doped onto the surface, to construct a flexible cobalt ferrite thin film with magnetoelasticity. The flexible film, combined with the cobalt ferrite nanoparticles and a reduced gold layer, exhibits excellent electromagnetic properties and has extremely wide applications. The flexible cobalt ferrite thin film is flexible, biocompatible, and highly suitable for biological, medical, and biochemical detection applications.
[0021] 2. Gold nanolayers are prepared by the reduction reaction of chloroauric acid, potassium bicarbonate, and glucose. The excellent biocompatibility and adsorption properties of gold layers allow the film to be modified with various aptamers, including antibodies. This enables flexible cobalt ferrite films to detect different antigens depending on the modified antibodies, increasing the utilization rate of cobalt ferrite films and expanding their application range.
[0022] 3. Based on the excellent biocompatibility of AuNPs, mercaptoethylamine is self-assembled onto a flexible magnetic film, and NHS and EDC-activated antibodies are modified on the surface of the magnetoelastic film. This allows for the design of novel and low-cost biosensors that can detect various substances based on antigen-antibody specific recognition. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of the flexible cobalt ferrite thin film biosensor described in this invention;
[0024] In the figure, 1-PDMS film; 2-cobalt ferrite nanoparticles; 3-gold nanoparticles; 4-antibody; 5-antigen. Detailed Implementation
[0025] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.
[0026] This embodiment provides a flexible cobalt ferrite thin film biosensor and its preparation method, referring to... Figure 1 The flexible cobalt ferrite thin film biosensor is based on a flexible cobalt ferrite / PDMS thin film. The surface of the flexible cobalt ferrite / PDMS thin film is doped with an AuNPS nano-gold layer. The AuNPS nano-gold layer is modified with an antibody. The flexible cobalt ferrite / PDMS thin film is obtained by adding cobalt ferrite nanoparticles to the A-resin of PDMS to obtain a cobalt ferrite nanogel fluid, and then mixing the cobalt ferrite nanogel fluid with the B-resin of the PDMS thin film. The mass ratio of cobalt ferrite nanoparticles to the A-resin of PDMS is 1:5.
[0027] The flexible cobalt ferrite thin film biosensor and its preparation method specifically include the following steps:
[0028] Select basic materials: cobalt ferrite nanoparticles, PDMS, potassium bicarbonate, chloroauric acid, and glucose;
[0029] a) Preparation of flexible cobalt ferrite / PDMS thin films
[0030] Before preparing the flexible film, cobalt ferrite nanoparticles were dispersed in PDMS gel A to prepare cobalt ferrite nanofluid. 2g of cobalt ferrite nanoparticles were weighed and added to 10g of gel A at a ratio of 1:5. The gel was then thoroughly stirred in a beaker for 10 minutes to ensure that the cobalt ferrite nanoparticles were uniformly and finely dispersed in gel A, resulting in a homogeneous cobalt ferrite nanogel fluid.
[0031] The specific process for preparing flexible cobalt ferrite / PDMS thin films:
[0032] (1) Mix the gel and PDMS film B adhesive at a ratio of 10:1; and stir continuously with a glass rod until uniform and dense bubbles are generated. Seal and let stand for 4 hours.
[0033] (2) After the air bubbles in the solution have completely disappeared, proceed with film formation. Place a glass slide on the tray of a spin coater, and after adsorption, pour in an appropriate amount of gel and spin coat at 300 rpm for 90 seconds to form a film. When the gel is evenly spread on the glass slide without any gaps, it can be dried.
[0034] (3) Carefully use tweezers to pick out the glass slide and place it on a dryer to dry at 100°C for 20 minutes to obtain a flexible iron-cobalt film.
[0035] b) Reduction of AuNPs on the thin film surface
[0036] (1) Prepare a 0.2 g / ml solution of potassium bicarbonate and glucose, and take 9.78 ml of potassium bicarbonate solution and 0.96 ml of glucose solution for later use;
[0037] (2) Rinse the 4mm×4mm chip repeatedly with deionized water to prevent surface dust from affecting the reduction effect;
[0038] (3) Place the chip flat on the bottom of a clean culture dish, and add potassium bicarbonate solution, glucose solution, 2.25 ml chloroauric acid, and 30.36 ml deionized water in sequence. After mixing, remove air bubbles from the film surface and react in the dark for 18 hours. After the reaction is complete, the gold layer on the film surface will be used as a sensing platform on the substrate.
[0039] c) Antibody modification
[0040] (1) The flexible film was cleaned in deionized water for 5 min using an ultrasonic sensor. After cleaning, the film was allowed to air dry naturally. Then, the cleaned sensor chip was immersed in a 40 mM mercaptoethylamine solution and placed at room temperature in the dark for 12 h to form a self-assembled membrane (SAM). The sensor chip with the SAM formed was removed from the mercaptoethylamine solution, the mercaptoethylamine was extracted with a pipette, and PBS solution was added and soaked for 30 min to remove the mercaptoethylamine that was not completely fixed on the surface.
[0041] (2) The antibody solution was then diluted with PBS to obtain an appropriate antibody concentration. At room temperature, the antibody solution was mixed with a solution containing 4 mg / mL EDC and 4 mg / mL NHS and shaken for 30 minutes to activate the carboxyl groups in the antibody into NHS esters, thereby enabling them to bind more efficiently to the amino groups on the surface of the self-assembled layer.
[0042] (3) Finally, the sensor chip was immersed in the activated antibody solution and placed at 37°C for 1 h to allow it to bind uniformly to the surface of the sensor chip. Then, the antibody-modified sensor chip was removed from the solution and diluted in PBS solution. The PBS solution containing the chip was placed at 37°C for 0.5 h to remove the antibodies physically adsorbed on the surface. At this point, the magnetostrictive immunosensor chip for detection was prepared.
[0043] This embodiment utilizes a combination of cobalt ferrite nanoparticles and PDDMS, with AuNPS nanoparticles doped onto the surface, to construct a flexible cobalt ferrite film with magnetoelasticity. By modifying different antibodies, different antigens can be detected, increasing the utilization rate of the cobalt ferrite film and expanding its application range. Because PDMS was chosen as the substrate for the flexible cobalt ferrite film, it offers greater flexibility compared to rigid alloy materials.
[0044] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all of these should be considered to fall within the scope of patent protection determined by the submitted claims.
Claims
1. A flexible cobalt ferrite thin film biosensor, characterized in that, The film includes a flexible cobalt ferrite / PDMS film; the surface of the flexible cobalt ferrite / PDMS film is doped with an AuNPS gold nanoparticle layer; the AuNPS gold nanoparticle layer is modified with an antibody; The flexible cobalt ferrite / PDMS film is obtained by adding cobalt ferrite nanoparticles to the A-type adhesive of PDMS to obtain a cobalt ferrite nanogel fluid, and then mixing the cobalt ferrite nanogel fluid with the B-type adhesive of PDMS film; the mass ratio of cobalt ferrite nanoparticles to the A-type adhesive of PDMS is 1:4-6; the mass ratio of cobalt ferrite nanogel fluid to the B-type adhesive of PDMS film is 10-13:
1.
2. The flexible cobalt ferrite thin film biosensor according to claim 1, characterized in that, The mass ratio of cobalt ferrite nanoparticles to PDMS A-type adhesive is 1:
5.
3. A method for preparing a flexible cobalt ferrite thin film biosensor as described in claim 1 or 2, characterized in that, Includes the following steps: 1) Preparation of flexible cobalt ferrite / PDMS film: Cobalt ferrite nanoparticles were dispersed in PDMS A-resin to obtain a uniform cobalt ferrite nanogel fluid; the mass ratio of cobalt ferrite nanoparticles to PDMS A-resin was 1:4-6; the cobalt ferrite nanogel fluid was mixed with PDMS film B-resin to obtain a flexible cobalt ferrite / PDMS film. 2) Reduction of AuNPs on the film surface: The flexible cobalt ferrite / PDMS film is immersed in chloroauric acid solution and reacted in the dark for 16-20 hours; AuNPS nano-gold layer is doped on the surface of the flexible cobalt ferrite / PDMS film. 3) Antibody modification: A flexible cobalt ferrite / PDMS film doped with AuNPS nano-gold layer is immersed in a mercaptoethylamine solution to form a self-assembled membrane. Then, the self-assembled membrane is immersed in an activated antibody solution to allow the antibody to bind uniformly to the surface of the self-assembled membrane.
4. The method for preparing a flexible cobalt ferrite thin film biosensor according to claim 3, characterized in that, The mass ratio of cobalt ferrite nanoparticles to PDMS A-type adhesive is 1:
5.
5. The method for preparing a flexible cobalt ferrite thin film biosensor according to claim 3, characterized in that, The flexible cobalt ferrite / PDMS film doped with AuNPS gold nanolayers was ultrasonically cleaned and air-dried before being immersed in a chloroauric acid solution.
6. The method for preparing a flexible cobalt ferrite thin film biosensor according to claim 3, characterized in that, The antibody solution was diluted and activated: the antibody solution was diluted with PBS solution to obtain an appropriate antibody concentration; at room temperature, the antibody solution was mixed and shaken with a solution containing 4 mg / mL EDC and 4 mg / mL NHS to activate the carboxyl groups in the antibody into NHS esters, so that the antibody could bind more efficiently to the amino groups on the surface of the self-assembled layer.
7. The method for preparing a flexible cobalt ferrite thin film biosensor according to claim 3, characterized in that, The antibody-modified self-assembled membrane was immersed in PBS solution; The PBS solution containing the chip was placed in an environment of 37°C and allowed to stand for 0.5 h to remove the antibodies that were physically adsorbed on the surface.