Nanodendritic sb2s3 array-based biodetection sensor and application in detection of miRNA-155

Abstract

The application belongs to the technical field of biosensing detection, and discloses a kind of based on nanodendritic Sb2S3 array biological detection sensor and its detection method.The application grows preferential orientation one-dimensional Sb2S3 nanorod crystal array on FTO / TiO2 substrate surface;Then secondary nanorod is grown on nanorod to form dendritic structure;Spray gold nanoparticle layer;Then, by the steric hindrance effect generated after specific binding of MiRNA-155 and target MiRNA, the hindering effect of charge transfer of photoelectrochemical biosensor of MiRNA-155 causes photocurrent signal change, so as to realize the detection of MiRNA-155.The biological detection sensor realizes ultra-high sensitivity detection.This kind of biological sensor based on nanodendritic Sb2S3 array has simple preparation method, strong detection specificity and easy operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biosensing detection, and provides a nano-dendritic Sb2S3 array-based biological detection sensor, a construction method thereof and application of the biological detection sensor in detection of MiRNA-155. BACKGROUND

[0002] MiRNA-155 has a wide range of functions and is involved in various biological processes. It is highly expressed in various cancers such as liver cancer, lymphoma, pancreatic cancer and lung cancer, and is closely related to the occurrence, invasion and metastasis of tumors. Detection of the concentration of MiRNA-155 has both necessary and important significance in cancer research. One of the main challenges in current cancer research is to develop an accurate diagnostic method before tumor metastasis. Photoelectrochemical sensors, as a simple, rapid and sensitive new technology, have received extensive attention and application in the field of analytical detection technology. Photoelectrochemical sensors effectively reduce the interference of background signals by separating excitation signals and response signals, and have ultra-high sensitivity and excellent stability.

[0003] The unique quasi-1D (Q1D) crystal structure of Sb2S3 endows Sb2S3 with highly anisotropic photoelectric properties. The conductivity along the C-axis direction is much higher than that in other directions, and it is easier to grow or break in the C-axis direction, which also provides convenience for the preparation of nano-branch crystals. Although nano-branch crystals have been successfully prepared, they are mainly laid on the plane and do not grow along the C-axis direction. The carrier diffusion length of this structure of Sb2S3 is limited, and the carriers are prone to recombination, which greatly affects the light capture ability and the transmission of carriers, which hinders the full utilization of light. In order to achieve better light capture and avoid carrier transmission loss, the application provides a convenient and effective method to construct a nano-dendritic Sb2S3 array structure. This array structure not only can improve the light capture and energy collection efficiency, but also can increase the specific surface area, which is helpful for the attachment of the detected substance, amplifies the detection signal and improves the detection efficiency. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art. The first purpose of the present application is to provide a nano-dendritic Sb2S3 array-based biological detection sensor, which has good reproducibility, good stability and high photoelectric current signal response. The second purpose of the present application is to provide a construction method of a nano-dendritic Sb2S3 array-based biological detection sensor, which has the advantages of simple operation and low cost.

[0005] In order to achieve the above object, the technical scheme adopted by the present application is: a construction method of a biological detection sensor based on nanodendritic Sb2S3 array, which is sequentially stacked from top to bottom as substrate glass FTO, TiO2 film layer, Sb2S3 rod array layer, anatase phase TiO2 film layer, Sb2S3 dendritic array layer, AuNPs layer, and then sequentially adding target SH-RNA, blocking agent 6-mercapto-1-hexanol (MCH), and incubating the measured substance (MiRNA-155).

[0006] The specific preparation method comprises the following steps:

[0007] Step 1: cleaning of substrate glass FTO;

[0008] Step 2: preparation of TiO2 film layer: a titanium source precursor solution A is prepared by using tetrabutyl titanate, acetylacetone and anhydrous ethanol, the precursor solution A is spin-coated on the substrate glass FTO in step 1, and then annealing treatment is performed to obtain the TiO2 film layer, i.e. TiO2 / FTO.

[0009] Step 3: preparation of Sb2S3 nanorod array layer: the sulfur source is thiourea, the antimony source is antimony chloride, the molar ratio of thiourea and antimony chloride is 1:1.8, thiourea and antimony chloride are dissolved in N,N-dimethylformamide by stirring until completely dissolved, Sb2S3 precursor solution B with a concentration of 0.1-0.3 mol / L and Sb2S3 precursor solution C with a concentration of 0.7-0.9 mol / L are prepared. After the TiO2 / FTO film layer in step 2 is treated by oxygen plasma machine for 10-30 min, 100 μL of the precursor solution B is spin-coated, and after annealing, it is naturally cooled; after being treated by oxygen plasma machine for 10-30 min, the precursor solution C is spin-coated for 2-5 times; a one-dimensional rod array of Sb2S3 is obtained, i.e. rod array Sb2S3 / TiO2 / FTO.

[0010] Step 4: Preparation of Sb2S3 nanodendritic array layer: The titanium source precursor solution A is spin-coated on the rod array Sb2S3 / TiO2 / FTO described in step 3, and then a hydrolysis treatment is performed to obtain a TiO2 film layer. The TiO2 / rod array Sb2S3 / TiO2 / FTO is obtained. After the TiO2 / rod array Sb2S3 / TiO2 / FTO film layer is treated by an oxygen plasma machine for 10-30 min, a Sb2S3 precursor solution B with a concentration of 0.1-0.3 mol / L is spin-coated, and after annealing, it is naturally cooled. After the oxygen plasma machine is treated for 10-30 min, a Sb2S3 precursor solution D with a concentration of 0.4-0.6 mol / L is spin-coated, and after annealing, it is naturally cooled. The number of repetitions of spin-coating the precursor solution D is 2 times. The dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO is obtained.

[0011] Further, the specific cleaning sequence in step 1 is: sequentially using conductive glass cleaning solution, deionized water, isopropanol, and alcohol for ultrasonic cleaning for 30 min, and the substrate glass is FTO glass.

[0012] As a preferred solution, the volume ratio of tetrabutyl titanate, acetylacetone, and anhydrous ethanol in step 2 is 10:3:100.

[0013] As a preferred solution, the spin coating in step 2 is set to rotate at a speed of 2000 rpm / min for 20 s, and then annealed at 250°C for 30 min in a muffle furnace, and then annealed at 500°C for 30 min.

[0014] As a preferred solution, the spin coating in step 3 is set to rotate at a speed of 3000 rpm / min for 30 s, and then pre-annealed at 150°C for 5 min, and then annealed at 300°C for 10 min, and finally naturally cooled.

[0015] As a preferred solution, the hydrolysis post-treatment of TiO2 in step 4 is performed in an air humidity of 70% for 5 h.

[0016] Application of the dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO as a biological detection sensor for detecting MiRNA-155.

[0017] (1) AuNPs is sprayed on the dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO to obtain an AuNPs / dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO electrode material;

[0018] (2) The probe RNA is dropped on the AuNPs / dendritic Sb2S3 / TiO2 / FTO and incubated at 4℃ for 6h, and then the unlinked probe RNA is removed by washing with buffer to obtain SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO.

[0019] (3) The 10mmol / L 6-mercapto-1-hexanol (MCH) solution is dropped on the SH-RNA / AuNPs / Sb2S3 / TiO2 / FTO and incubated at 25℃ for 0.5h, and then the analyte MiRNA-155 in the concentration range of 1fm-0.1μm is dropped on the MCH / SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO to obtain the MCH / SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO modified by different concentrations of MiRNA-155.

[0020] (4) The MCH / SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO modified by different concentrations of MiRNA-155 is used as a working electrode, a platinum wire is used as a counter electrode, and Ag / AgCl is used as a reference electrode to form a three-electrode system for photoelectrochemical signal detection. The electrode detection solution is a PBS buffer containing ascorbic acid (AA) (the concentration of the buffer is 0.1M, and the pH is 7.4). The light source is an LED lamp, and the applied potential is 0V. The photocurrent is recorded when the electrode detects different concentrations (the detection concentration range is 1fm-0.1μm) of MiRNA-155, and the relationship between the photocurrent intensity and different concentrations of MiRNA-155 is established.

[0021] Further, the Sb2S3 / TiO2 / Sb2S3 / TiO2 / FTO is sprayed in a gold spraying instrument for 2min to obtain a gold nanoparticle layer.

[0022] As a preferred solution, the concentration of the probe RNA is 0.5μM-15μM.

[0023] Further, the incubation condition of the analyte MiRNA-155 in step 5 is 37℃ for 1h.

[0024] Further, the oligonucleotide sequence of the SH-RNA in step 5 is 5'-SH-ACCCCUAUCACGAUUAGCAUU, and the oligonucleotide sequence of the MiRNA-155 is 5'-UUAUGCUAAUCGUGAUAAGGGGU-3'.

[0025] As a preferred solution, the pH of the PBS buffer in step 5 is 7.4, and the concentration is 0.1M.

[0026] The application has the following three advantages:

[0027] One, Sb2S3 / TiO2 has good band matching, forms a well-matched heterojunction structure, effectively reduces the interface recombination, and further improves the separation rate of photo-generated carriers;

[0028] Two, the seed-assisted spin coating method effectively improves the growth orientation of Sb2S3, makes the quasi-one-dimensional Sb2S3 molecular chain more inclined to vertical growth, and significantly improves the carrier transmission inside the absorption layer film;

[0029] Three, the Sb2S3 nanorod array has a larger specific surface area, not only provides more active sites for the measured object, which is conducive to the adhesion of the measured object, but also improves the light utilization rate, better realizes light capture and avoids the loss of carriers. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The experimental flowchart of the application example;

[0031] Figure 2 The ultraviolet absorption contrast chart of Sb2S3 of the application example 1 and example 2;

[0032] Figure 3 The ultraviolet absorption chart of Sb2S3 of the application example 3;

[0033] Figure 4 The Sb2S3 X-ray diffraction chart of the application example 4;

[0034] Figure 5 The scanning electron microscope chart of Sb2S3 of the application example 3;

[0035] Figure 6 The ultraviolet absorption chart of Sb2S3 of the application example 4;

[0036] Figure 7 The scanning electron microscope chart of Sb2S3 of the application example 4;

[0037] Figure 8 The X-ray diffraction chart of hydrolyzed TiO2 of the application comparative example 1;

[0038] Figure 9 The I-T curve chart of the application example 5;

[0039] Figure 10 The ultraviolet absorption chart of Sb2S3 of the application example 6;

[0040] Figure 11 Linear fit curve for I-T curve and its detection limit of Example 7 of the present application.

[0041] Figure 12 Reproducibility curve plot of Example 8 of the present application.

[0042] Figure 13 Stability curve plot of Example 9 of the present application.

[0043] Figure 14 Selectivity curve plot of Example 10 of the present application. DETAILED DESCRIPTION

[0044] Example 1: Rod array Sb2S3 / TiO2 / FTO working electrode

[0045] Step 1: FTO substrate glass (1.5 cm x 2.5 cm) was sequentially cleaned with conductive glass cleaning solution, deionized water, isopropanol, and alcohol for 30 min each by ultrasonic cleaning, and then the cleaned FTO conductive glass was immersed in anhydrous ethanol and sealed with tin foil paper to store.

[0046] Step 2: Tetrabutyl titanate, acetylacetone, and anhydrous ethanol were mixed in a volume ratio of 10:3:100, and then stirred at room temperature (24-30°C) for 2 h to obtain precursor solution A; the cleaned FTO conductive glass was blown dry with an air gun, and then subjected to 20 min of ultraviolet ozone treatment; precursor solution A was filtered with a filter core with a pore size of 0.45 μm, and then 100 μL of the filtered precursor solution A was dropped onto the treated FTO conductive glass using a pipette, and spin-coated at a rotation speed of 2000 rpm / min for 20 s; immediately after spin-coating, it was transferred to a muffle furnace, sintered at 250°C for 30 min, and then sintered at 500°C for 30 min to obtain TiO2 / FTO.

[0047] Step 3: 0.02261 g of antimony chloride and 0.0137 g of thiourea were weighed and dissolved in 1 ml of N,N-dimethylformamide, and then stirred at room temperature (24-30 °C) for 30 min to obtain a precursor solution B of 0.1 mol / l. The TiO2 / FTO in step 2 was subjected to 20 min of ozone treatment. After the treatment, it was transferred into a glove box together with the precursor solution B. 100 μL of the precursor solution B was dropped on the TiO2 / FTO using a pipette, and the spin-coating speed was set to 3000 rpm / min for 30 s. Immediately after the spin-coating, it was pretreated on a 150 °C hot stage for 5 min, and then transferred to a 300 °C hot stage for 10 min, and finally allowed to cool to room temperature naturally. Again, 0.1808 g of antimony chloride and 0.1096 g of thiourea were weighed and dissolved in 1 ml of N,N-dimethylformamide, and then stirred at room temperature (24-30 °C) for 30 min to obtain a precursor solution C of 0.8 mol / l. After the Sb2S3 / TiO2 / FTO film was treated in an oxygen plasma machine for 20 min, 100 μL of the precursor solution C was dropped on the Sb2S3 / TiO2 / FTO film using a pipette, and the spin-coating speed was set to 3000 rpm / min for 30 s. Immediately after the spin-coating, it was pretreated on a 150 °C hot stage for 5 min, and then transferred to a 300 °C hot stage for 10 min, and finally allowed to cool to room temperature naturally. After 20 min of oxygen plasma treatment, 100 μL of the precursor solution C was spin-coated 4 times with the same spin-coating settings, and then subjected to the same annealing treatment to obtain a rod array Sb2S3 / TiO2 / FTO.

[0048] Example 2: Dendritic array Sb2S3 / TiO2 / FTO working electrode

[0049] Step 1: The FTO substrate glass was sequentially ultrasonically cleaned with conductive glass cleaning solution, deionized water, isopropanol, and alcohol for 30 min each, and then immersed in anhydrous ethanol and sealed with tin foil paper for storage.

[0050] Step 2: Tetrabutyl titanate, acetylacetone, and anhydrous ethanol were mixed in a volume ratio of 10:3:100, and then stirred at room temperature (24-30 °C) for 2 h to obtain a precursor solution A. The cleaned FTO conductive glass was blown dry with an air gun, and then subjected to 20 min of ultraviolet ozone treatment. The precursor solution A was filtered with a filter cartridge with a pore size of 0.45 μm, and then 100 μL of the filtered precursor solution A was dropped on the treated FTO conductive glass using a pipette, and the spin-coating speed was 2000 rpm / min for 20 s. Immediately after the spin-coating, it was transferred to a muffle furnace, sintered at 250 °C for 30 min, and then sintered at 500 °C for 30 min to obtain TiO2 / FTO.

[0051] Step 3: 0.02261 g of antimony chloride, 0.0137 g of thiourea were weighed and dissolved in 1 ml of N,N-dimethylformamide, then stirred at room temperature (24-30 °C) for 30 min to obtain a precursor solution B of 0.1 mol / l. The TiO2 / FTO in step 2 was treated with ozone for 20 min. After treatment, it was transferred to the glove box together with the precursor solution B. 100 μL of the precursor solution B was dropped on the TiO2 / FTO using a pipette, and the spin coating speed was set to 3000 rpm / min for 30 s. After spin coating, it was immediately pretreated on a 150 °C hot stage for 5 min, then transferred to a 300 °C hot stage for 10 min, and finally naturally cooled to room temperature; 0.1808 g of antimony chloride, 0.1096 g of thiourea were weighed and dissolved in 1 ml of N,N-dimethylformamide, then stirred at room temperature (24-30 °C) for 30 min to obtain a precursor solution C of 0.8 mol / l; the Sb2S3 / TiO2 / FTO film was treated with oxygen plasma for 20 min, then 100 μL of the precursor solution C was dropped on the Sb2S3 / TiO2 / FTO film using a pipette, and the spin coating speed was set to 3000 rpm / min for 30 s. After spin coating, it was immediately transferred to a 150 °C hot stage for pretreatment for 5 min, then transferred to a 300 °C hot stage for 10 min, and finally naturally cooled to room temperature. After 20 min of oxygen plasma treatment, 100 μL of the precursor solution C was spin-coated 4 times with the same spin coating settings, then the same annealing treatment was performed to obtain the rod array Sb2S3 / TiO2 / FTO.

[0052] Step 4: The precursor solution A was filtered by a filter with a pore size of 0.45 μm, and then 100 μL of the filtered precursor solution A was dropped on the rod array Sb2S3 / TiO2 / FTO working electrode by a pipette, and spin-coated at a speed of 2000 rpm / min for 20 s, and then transferred to a sealed container with an air humidity of 70% for 5 h to obtain the anatase TiO2 / rod array Sb2S3 / TiO2 / FTO working electrode. After treatment in the oxygen plasma machine for 20 min, 100 μL of the precursor solution B was dropped on the anatase TiO2 / rod array Sb2S3 / TiO2 / FTO working electrode by a pipette, and spin-coated at a speed of 3000 rpm / min for 30 s, and then preheated at 150°C for 5 min, and then transferred to a hot stage at 300°C for 10 min, and finally naturally cooled to room temperature to obtain Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO. Then 0.0904 g of antimony chloride and 0.0548 g of thiourea were weighed and dissolved in 1 ml of N,N-dimethylformamide to obtain a precursor solution D with a concentration of 0.4 mol / L, and then stirred at room temperature (24-30°C) for 30 min. Before spin-coating, the precursor solution D was transferred to the oxygen plasma machine for treatment for 20 min, and then 100 μL of the precursor solution D was dropped on the Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO by a pipette, and spin-coated at a speed of 3000 rpm / min for 30 s, and then preheated at 150°C for 5 min, and then transferred to a hot stage at 300°C for 10 min, and finally naturally cooled to room temperature. After treatment in the oxygen plasma machine for 20 min, the same amount of the precursor solution D was spin-coated again, and then the same annealing treatment was performed to obtain the dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO working electrode.

[0053] Figure 2 The UV absorption of Sb2S3 in Example 1 and Example 2 of the present application is shown in the figure. Figure 2 It can be seen that the light absorption of the dendritic array Sb2S3 is greater than that of the rod array Sb2S3, and the light utilization rate is higher, so for the subsequent detection of MiRNA-155, the dendritic array Sb2S3 is used for detection.

[0054] Example 3

[0055] The difference between Example 3 and Example 1 is only that the concentration of the 0.1 mol / L precursor solution B is replaced by 0.2 mol / L and 0.4 mol / L, respectively, and the other conditions are the same, and the rod array Sb2S3 / TiO2 / FTO working electrode is prepared.

[0056] From Figure 3 ,4 It can be seen that in the range of 0.1-0.4 mol / L, with the increase of the concentration of precursor solution B, the absorption of visible light is gradually enhanced, the characteristic peak of (001) orientation is gradually obvious, but the lateral size of nanorods gradually increases, from nanorod array to cuboid array, which makes the density of rod array too large, and is not conducive to the growth of subsequent dendrites, so 0.1 mol / L is selected as the concentration of precursor solution B.

[0057] Example 4

[0058] In this example 4, the influence of total spin-coating times is studied, the total spin-coating times of precursor solution C are 2, 3, 4 times, and the other conditions are consistent with example 1, to prepare rod array Sb2S3 / TiO2 / FTO working electrode. From Figure 6 It can be seen that with the increase of spin-coating times, the length of nanorods gradually increases, from Figure 7 It can be seen that the absorption of ultraviolet-visible light is also higher, so N=5 is selected as the spin-coating times.

[0059] Comparative example 1

[0060] Comparative example 1 and example 2 are different in that: in step 4, after spin-coating precursor solution A, hydrolysis is not carried out, but sintering. At this time, Sb2S3 in rod array Sb2S3 / TiO2 / FTO cannot withstand high temperature of 500℃ and will volatilize, so dendrite Sb2S3 cannot be prepared. According to the epitaxial relationship between Sb2S3 crystal surface and anatase TiO2 crystal surface, it can be known that only TiO2 nanoparticle film with (101) plane exposed on the substrate surface has high matching degree with Sb2S3, and Sb2S3 crystal seed with

[211] /

[221] orientation grows outward along

[001] direction. Figure 8 is the XRD pattern of hydrolyzed titanium oxide, from Figure 8 It can be seen that anatase TiO2 is obtained. The (101) crystal surface of anatase TiO2 matches with (kh1) of antimony sulfide, forming dendritic Sb2S3.

[0061] Example 5

[0062] Example 5 and example 2 are different in that: the influence of the concentration of precursor solution B on dendritic array Sb2S3 in step 4. From Figure 9 It can be seen that the current response of dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO working electrode is the highest when the concentration of precursor solution B is 0.1 mol / L, so 0.1 mol / L concentration of precursor solution B is selected to prepare dendritic array Sb2S3.

[0063] Example 6

[0064] Example 6 is compared with Example 2, the difference is that the effect of the number of spin coating of precursor solution D of step 4 on the ultraviolet absorption. As shown in Figure 10 the ultraviolet absorption of spin coating 2 times of precursor solution D is greater than spin coating 1 time, and it has higher utilization of light, so N = 2 is selected as the spin coating number of dendritic Sb2S3.

[0065] Example 7

[0066] Example 7 is different from Example 2 in that different concentrations of MiRNA-155 are dropped on the working electrode, and the related experiments of sensor performance test are increased.

[0067] Steps 1-4: The dendritic array Sb2S3 / TiO2 / FTO working electrode is prepared, and the operation is the same as that of Example 2.

[0068] Step 5: The dendritic array Sb2S3 / TiO2 / FTO working electrode is sprayed in the gold spraying instrument for 2 min to obtain a gold nanoparticle layer.

[0069] Step 6: 15 μL of 2 μM probe RNA is dropped on the AuNPs / dendritic Sb2S3 / TiO2 / FTO and incubated at 4°C for 6 h, and then washed with buffer for 3 times to remove the unconnected probe RNA, to obtain SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO.

[0070] Step 7: 20 μL of 10 mmol / L MCH solution is dropped on the SH-RNA / AuNPs / Sb2S3 / TiO2 / FTO and incubated at 25°C for 0.5 h, and then different concentrations of the test substance MiRNA-155 in the concentration range of 1 fm-0.1 μm are dropped on the MCH / SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO to obtain MiRNA-155 / MCH / SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO.

[0071] Step 8: MiRNA-155 / MCH / SH-RNA / AuNPs / dendritic Sb2S3 / TiO2 / FTO is used as the working electrode, platinum wire is used as the counter electrode, and Ag / AgCl is used as the reference electrode to form a three-electrode system for photoelectrochemical signal detection. The electrode detection solution is PBS buffer containing ascorbic acid (AA) (the concentration of the buffer is 0.1 M, and the pH is 7.4). The light source is LED lamp, and the applied potential is 0 V. The photocurrent is recorded when the electrode detects different concentrations of MiRNA-155, and the relationship between the photocurrent intensity and different concentrations of MiRNA-155 (the detection concentration range is 1 fm-0.1 μm) is established.

[0072] AsFigure 11 As shown, the photocurrent gradually increases with decreasing concentration of miRNA-155 in the hybridization reaction. Linear regression analysis revealed a linear relationship between the photocurrent and the logarithm of the miRNA-155 concentration in the 1 fm-0.1 μm range. The linear regression equation was I(μA) = 13.29 * lgc + 32.82, with a linear correlation coefficient R = 0.996 and a detection limit of 0.9 fm.

[0073] Example 8

[0074] The difference between this embodiment and Embodiment 7 is that: a concentration of 1 pM miRNA-155 was selected, and more than 10 cycles of light-on and light-off were performed within 550 seconds, while all other conditions remained the same. Figure 12 It was found that the measured photocurrent signal did not change significantly, and its relative standard deviation (RSD) was only 0.76%, indicating that the proposed biosensor has good stability.

[0075] Example 9

[0076] The difference between this embodiment and Example 7 is that five biosensors were independently prepared using 1 pM miRNA-155, while all other conditions remained the same. Figure 13 It can be seen that the photocurrent differences among the five biosensors are small, indicating that the proposed biosensors have significant reproducibility.

[0077] Example 10

[0078] The difference between this embodiment and Example 7 is that mismatched sequences Mix, miRNA-21, miRNA-141, and miRNA-182 at a concentration of 1 pM were selected as controls to detect the selectivity of the PEC biosensor. The measured photocurrent response is as follows: Figure 14 As shown, the photocurrent containing miRNA-155 was significantly higher than that in the control group, indicating that the PEC biosensor can selectively detect target sequences.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nanodendritic Sb2S3 array-based biosensor for biological detection, characterized in that: The biological detection sensor is MCH / SH-RNA / AuNPs / dendritic Sb2S3 / anatase TiO2 / rod array Sb2S3 / TiO2 / FTO; wherein the oligonucleotide sequence of SH-RNA is 5'-SH-ACCCCUAUCACGAUUAGCAUU; The preparation method of the dendritic array Sb2S3 / anatase TiO2 / rod array Sb2S3 / TiO2 / FTO is as follows: (1) SbCl3 and thiourea are weighed and dissolved in a solvent to prepare Sb2S3 precursor solution B with a concentration of 0.1-0.3 mol / L and Sb2S3 precursor solution C with a concentration of 0.7-0.9 mol / L, respectively; TiO2 / FTO is treated by an oxygen plasma machine, Sb2S3 precursor solution B is dropped on the treated TiO2 / FTO and spin-coated, annealing treatment is performed after spin-coating, and finally the sample is naturally cooled to room temperature to obtain Sb2S3TiO2 / FTO; Sb2S3 precursor solution C is spin-coated on the film of Sb2S3TiO2 / FTO, and after annealing treatment, Sb2S3 precursor solution C is repeatedly spin-coated for 2-5 times to obtain rod array Sb2S3 / TiO2 / FTO; (2) Ti source precursor A is spin-coated on the rod array Sb2S3 / TiO2 / FTO to obtain anatase TiO2 / rod array Sb2S3 / TiO2 / FTO by hydrolysis, Sb2S3 precursor solution B is spin-coated, and after annealing treatment, 0.4-0.6 mol / L Sb2S3 precursor solution D is spin-coated, and after annealing treatment, Sb2S3 precursor solution D is repeatedly spin-coated for 1-2 times to obtain dendritic array Sb2S3 / anatase TiO2 / rod array Sb2S3 / TiO2 / FTO electrode.

2. The preparation method of the biological detection sensor based on nanodendritic Sb2S3 array according to claim 1, characterized in that: (1) Ti source precursor A is spin-coated on FTO conductive glass, and TiO2 / FTO is obtained by sintering after spin-coating; (2) SbCl3 and thiourea are weighed and dissolved in a solvent to prepare Sb2S3 precursor solution B with a concentration of 0.1-0.3 mol / L and Sb2S3 precursor solution C with a concentration of 0.7-0.9 mol / L, respectively; TiO2 / FTO is treated by an oxygen plasma machine, Sb2S3 precursor solution B is dropped on the treated TiO2 / FTO and spin-coated, annealing treatment is performed after spin-coating, and finally the sample is naturally cooled to room temperature to obtain Sb2S3TiO2 / FTO; Sb2S3 precursor solution C is spin-coated on the film of Sb2S3TiO2 / FTO, and after annealing treatment, Sb2S3 precursor solution C is repeatedly spin-coated for 2-5 times to obtain rod array Sb2S3 / TiO2 / FTO; (3) spin titanium source precursor A on the rod array Sb2S3 / TiO2 / FTO to obtain TiO2 / rod array Sb2S3 / TiO2 / FTO with anatase phase, continue to spin Sb2S3 precursor solution B, after annealing, spin 0.4-0.6 mol / L Sb2S3 precursor solution D again, after annealing, repeat the spin of Sb2S3 precursor solution D for 1-2 times to obtain dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO electrode; (4) modify AuNPs layer on the electrode of step (3), then add target SH-RNA and blocking agent 6-mercapto-1-hexanol (MCH) in sequence to obtain MCH / SH-RNA / AuNPs / dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO biological detection sensor.

3. The method of claim 2, wherein: Titanium source precursor A is obtained by mixing tetrabutyl titanate, acetylacetone and anhydrous ethanol in a volume ratio of 10:3:100; Sb2S3 precursor solution is prepared by dissolving thiourea and antimony chloride in N,N-dimethylformamide in a molar ratio of 1:1.8, stirring until completely dissolved.

4. The method of claim 2, wherein: The annealing treatment of step (2) and step (3) is pre-annealing at 150℃ for 5 min, then annealing at 300℃ for 10 min, and finally natural cooling.

5. The use of the nano-dendritic Sb2S3 array-based biosensor prepared according to any one of claims 2-4 in the detection of MiRNA-155, characterized in that: Drop 1 fm-0.1 µm different concentrations of MiRNA-155 to be tested on the electrode to obtain MiRNA-155 / MCH / SH-RNA / AuNPs / dendritic array Sb2S3 / TiO2 / rod array Sb2S3 / TiO2 / FTO biological detection sensor, use this as working electrode, platinum wire as counter electrode, Ag / AgCl as reference electrode to form a three-electrode system for photoelectrochemical signal detection, electrode detection solution is PBS buffer containing ascorbic acid, detect the photocurrent of the electrode modified by different concentrations of MiRNA-155, establish the relationship between photocurrent intensity and different concentrations of MiRNA-155, obtain linear regression equation for detection of MiRNA-155 concentration; the oligonucleotide sequence of MiRNA-155 is 5'-UUA AUG CUA AUC GUG AUA GGG GU-3.

6. Use according to claim 5, characterised in that: The light source is LED lamp, and the applied potential is 0 V.

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