Fabrication and Application of MOF Derivative Organic Photochemical Transistor Sensors

Abstract

This invention provides the fabrication and application of an organic photoelectrochemical transistor sensor based on a MOF derivative. A tetrahedral Ce-MOF is prepared via a solvothermal method. The Ce-MOF is then derivatized into Ce-ZnIn2S4 using a one-pot method. Ce-ZnIn2S4 is then modified onto an FTO conductive glass surface using PAMAM. Y-DNA probes and double-stranded substrates are prepared: the Y-DNA probes are made by mixing equal amounts of single-stranded DNA, annealing, natural cooling, and cryogenic storage; the double-stranded substrates are prepared using the same method. The activated Y-DNA probes are used to modify the electrode surface. After washing with buffer, unbound active sites are blocked with MEA solution. After washing, miRNA-25 is added for incubation. After further washing, the electrode is immersed in a solution containing the hybridization substrate for incubation. Sensing detection is achieved using a nonlinear hybridization chain reaction, enabling sensitive detection of miRNA-25.

Description

Technical Field

[0001] This invention relates to the field of photoelectrochemical sensor technology, and more specifically, to the preparation and application of MOF derivative organic photoelectrochemical transistor sensors. Background Technology

[0002] Metal-organic frameworks (MOFs) are porous crystalline materials formed by the combination of metal ions and organic ligands. They possess advantages such as ordered structure and stable physicochemical properties, attracting increasing attention. A useful approach to further improve MOFs is to transform them into functional MOF derivatives with well-structured components but novel physicochemical properties, such as enhanced stability, electrochemical activity, and electronic conductivity. Notably, converting MOFs into semiconductor derivatives has proven to be a feasible route for developing new materials for various applications, such as energy storage, electromagnetic wave absorption, and photocatalysts.

[0003] Hybridization chain reaction (HCR) consists of a trigger sequence and two partially complementary hairpin probes. Once triggered, the two hairpin probes can hybridize autonomously and continuously. In recent years, nonlinear hybridization chain reaction (nHCR) has evolved traditional HCR from linear probe hybridization to complex branched probe hybridization. Compared with HCR, nHCR can achieve higher amplification ratios and molecular weights. This biosensing method can achieve highly sensitive and selective detection of biomolecules.

[0004] Organic electrochemical transistors (OECTs) have gained increasing research momentum in areas such as physiological signal monitoring, neuromorphic computing, and biointerfaces. Light, as a clean and ubiquitous energy source, has enabled the development of advanced optoelectronic technologies. The innovative synergy between light and OECTs has created photoactivated OECTs with new applications. This indicates that photoinduced V... G The changes not only power OECTs but also adjust the physical characteristics of the devices. Among these adjustments is the high current difference (Ro) between the power-on and power-off states. on / off It has been proven that for a fixed V G Maximizing signal transduction within the range is crucial. However, clearly distinguishing between power-on and power-off states requires a wider Vo. G This limitation is detrimental to both energy conservation and biological applications. Therefore, there is an urgent need to find novel functional materials to develop new organic photoelectrochemical transistor biosensors with high sensitivity and stability. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for fabricating a MOF derivative organic photoelectrochemical transistor biosensor, thereby resolving the current inability to clearly distinguish the switching state of transistors using simple methods, and the issue that MOF derivative organic electrochemical transistors have poor detection stability and sensitivity in biological applications.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The method for preparing a MOF derivative organic photoelectrochemical transistor sensor includes:

[0007] S1, Preparation of MOF derivative (Ce-ZnIn2S4):

[0008] Ce-MOF with tetradecahedron structure was prepared by solvothermal method. Ce-MOF was derivatized into Ce-ZnIn2S4 by one-pot method. Ce-ZnIn2S4 was then modified onto fluorine-doped SnO2 conductive glass (hereinafter referred to as FTO) by polyamide-amine dendritic polymer (hereinafter referred to as PAMAM), which became the electrode surface.

[0009] S2, Preparation of Y-DNA probe and double-stranded substrate:

[0010] Y-DNA probes consist of equal amounts of three single-stranded DNA molecules (Y... s1 ,Y s2 ,Y s3 The mixture is then annealed, allowed to cool naturally, and stored at low temperature for later use. Except for the corresponding single-stranded sequence, the double-stranded substrate is prepared using the same method as the Y-DNA probe. The sensor preparation is now complete.

[0011] S3 utilizes a nonlinear hybridization chain reaction for sensing and detection:

[0012] The activated Y-DNA probe from step S2 was used to modify the electrode surface prepared in step S1. After washing with Tris-HCl buffer (Tris-HCl, also known as tris(hydroxymethyl)aminomethane hydrochloride), the unbound active sites were blocked with monoethanolamine solution (hereinafter referred to as MEA solution). After washing, microRNA-25 (hereinafter referred to as miRNA-25) was added for incubation. After washing, the electrode was immersed in a solution containing hybridization substrate for incubation.

[0013] In the above technical solution, in step S1, when preparing the Ce-ZnIn2S4 sensor, acetic acid, NaClO4·H2O, and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (average molecular weight 12600, hereinafter referred to as F127) in a mass ratio of 4:6250:125 are mixed into 6 mL of deionized water to obtain a homogeneous solution. Subsequently, 167 mM (NH4)2Ce(NO3)6 and 167 mM terephthalic acid are added to the above solution, and the mixture is heated in a water bath. After the reaction is completed, the precipitate (Ce-MOF) is collected, washed successively with distilled water, DMF (N,N-dimethylformamide), and ethanol, and then dried under vacuum. The dried Ce-MOF is dispersed in 10 mL of a mixture of deionized water and glycerol in a volume ratio of 4:1 and stirred until homogeneous. Then, 40 mM InCl3·4H2O, 20 mM ZnCl2 and 80 mM thioacetamide (hereinafter referred to as TAA) were added to the mixture, and the mixture was heated in an oil bath. The resulting precipitate was collected, washed with ethanol and dried under vacuum.

[0014] In the above technical solution, the vacuum drying temperature in step S1 is 60℃.

[0015] In the above technical solution, in step S1, the FTO conductive glass needs to be ultrasonically cleaned with acetone, ethanol, and water for 10 minutes each before use.

[0016] In the above technical solution, in step S1, the concentration of PAMAM is 1 wt%.

[0017] In the above technical solution, in step S2, three single-stranded DNA strands (Y) dissolved in the hybridization buffer in equimolar amounts are... s1 ,Y s2 ,Y s3 Mix the samples and anneal at 95°C for 5 minutes to prepare γ-DNA. Cool naturally to room temperature and store at 4°C for later use. Except for the corresponding single-stranded sequences, all double-stranded substrate sequences were prepared using the same method.

[0018] In the above technical solution, in step S2, the hybridization buffer is prepared from 40mM Tris-HCl, 10mM MgCl2, and 2mM EDTA.

[0019] In the above technical solution, in step S3, well-dispersed Ce-ZnIn2S4 containing 1 wt% PAMAM is drop-fed onto an FTO electrode and dried at 37°C for 1 h to prepare a Ce-ZnIn2S4 gate. Then, Y-DNA activated by EDC / NHS crosslinking agent is modified onto the Ce-ZnIn2S4 gate surface and incubated at 4°C for 1 h to immobilize the Y-DNA. Unbound active sites on the gate are then blocked with MEA solution and incubated at 4°C for 1 h. Next, the gate is incubated with different concentrations of miRNA-25 or interfering substances at 35°C for 120 min, followed by incubation with nHCR components at 37°C for 3 h. Washing with washing buffer is performed after each modification.

[0020] In the above technical solution, in step S3, Y-DNA is activated by mixing it with a 5 mg / mL EDC / NHS solution and incubating it at 4°C for 1 h.

[0021] In the above technical solution, in step S3, miRNA-25 is dissolved in a competition buffer.

[0022] In the above technical solution, in step S3, the competition buffer is prepared from 1mM Tris-HCl, 25mM NaCl, and 1mM EDTA.

[0023] In the above technical solution, in step S3, the blocking buffer is 1mM ethanolamine (hereinafter referred to as MEA).

[0024] In the above technical solution, in step S3, the concentration of each component of nHCR is 40 nM.

[0025] One of the objectives of this invention is to provide a MOF derivative organic photoelectrochemical transistor biosensor, which is prepared by the above-described method.

[0026] The second objective of this invention is to provide an application of a MOF derivative organic photoelectrochemical transistor biosensor as a photoelectrochemical sensor in the detection of miRNA-25.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention combines MOF derivatives with organic photoelectrochemical transistors. PEDOT:PSS semiconductor thin films are modulated by Ce-doped ZnIn2S4 MOF derivatives. The interaction between light and Ce-ZnIn2S4 can appropriately alter the physical properties of the transistor device, giving the transistor a superior on / off ratio; under a fixed gate voltage V... GThis device achieves maximum signal transduction within its range. It binds to a dendritic DNA structure mediated by a nonlinear hybridization chain reaction, enabling sensitive detection of miRNA-25. Specifically, it offers the following advantages:

[0029] (1) This invention combines with organic photoelectrochemical transistors to obtain a photoelectrochemical biosensor based on Ce-ZnIn2S4. The fabrication process is simple and low-cost. Under a fixed VT G Increase transistor signal conduction within the range;

[0030] (2) Construct an OPECT sensor based on Ce-ZnIn2S4 to achieve sensitive detection of miRNA-25 with a detection limit of 1 fM;

[0031] (3) The MOF derivative Ce-ZnIn2S4 organic photoelectrochemical transistor sensor prepared by this invention has good stability and reusability, and has good prospects.

[0032] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0033] Figure 1 SEM image of Ce-MOF prepared in step S1 of this embodiment of the invention;

[0034] Figure 2 SEM image of Ce-ZnIn2S4 prepared in step S1 of this embodiment of the invention;

[0035] Figure 3 The UV-Vis absorption spectrum of Ce-MOF prepared in step S1 of this embodiment of the invention;

[0036] Figure 4 The ultraviolet-visible absorption spectrum of Ce-ZnIn2S4 prepared in step S1 of this embodiment of the invention;

[0037] Figure 5 Stability test diagram of the sensor prepared according to the embodiments of the present invention;

[0038] Figure 6 The response diagram of the sensor prepared in this embodiment of the invention to different concentrations of miRNA-25;

[0039] Figure 7 Standard curves of the sensor prepared in this embodiment of the invention for different concentrations of miRNA-25;

[0040] Figure 8 The sensor prepared according to the embodiments of the present invention is used for selective testing of the detection system. Detailed Implementation

[0041] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0042] The fabrication methods for MOF derivative organic photoelectrochemical transistor sensors include:

[0043] S1, Preparation of MOF derivative (Ce-ZnIn2S4):

[0044] Ce-MOF with tetradecahedral structure was prepared by a solvothermal method. Ce-MOF was then derivatized into Ce-ZnIn2S4 using a one-pot method. Ce-ZnIn2S4 was then modified onto fluorine-doped SnO2 conductive glass (FTO) using 1 wt% polyamide-amine dendritic polymer (PAMAM) to form the electrode surface. Specifically, in preparing the Ce-ZnIn2S4 sensor, 5.1 mmol of acetic acid, 3.5 mmol of NaClO4·H2O, and 100 mg of F127 were mixed into 6 mL of deionized water to obtain a homogeneous solution. Subsequently, 1 mmol of (NH4)2Ce(NO3)6 and 1 mmol of terephthalic acid were added to the above solution, and the mixture was stirred in a water bath at 60-80 °C for 20 min. After the reaction was completed, the precipitated Ce-MOF was collected, washed successively with distilled water, DMF (N,N-dimethylformamide), and ethanol, and then dried under vacuum. 20 mg of dried Ce-MOF was dispersed in a mixture of 8 mL deionized water and 2 mL glycerol, and stirred for 30 min. Then, 0.4 mmol InCl3·4H2O, 0.2 mmol ZnCl2, and 0.8 mmol TAA were added to the mixture, and the mixture was stirred in an oil bath at 60-80 °C for 1-2 h. The precipitate was collected, washed with ethanol, and vacuum dried to obtain Ce-ZnIn2S4. The vacuum drying temperature was 60 °C. The FTO conductive glass, Ce-MOF, and Ce-ZnIn2S4 have a size of approximately 700 nm; SEM images are shown below. Figure 1 and Figure 2 As shown, the ultraviolet-visible absorption spectrum is as follows: Figure 3 and Figure 4 As shown, by Figure 3 It can be seen that the prepared Ce-MOF tetrahedron has a smooth surface and a particle size of about 0.9 μm. After Ce-ZnIn2S4 is derived, it retains the tetrahedral structure and grows nanosheets on the surface with a particle size of about 1.3 μm.

[0045] S2, Preparation of Y-DNA probe and double-stranded substrate:

[0046] Y-DNA probes consist of equal amounts of three single-stranded DNA molecules (Y... s1 ,Y s2 ,Y s3 Mix the three single-stranded DNA molecules, anneal, allow to cool naturally, and store at low temperature for later use. Except for the corresponding single-stranded sequence, the double-stranded substrate is prepared using the same method as the Y-DNA probe. The sensor preparation is now complete. Specifically, three single-stranded DNA molecules (Y-DNA, Y ... s1 ,Y s2 ,Y s3 Mix the ingredients and anneal at 95°C for 5 min to prepare Y-DNA. Cool naturally to room temperature and store at 4°C for later use. Except for the corresponding single-stranded sequences, the double-stranded substrate sequences were prepared using the same method. The hybridization buffer was prepared with 40 mM Tris-HCl, 10 mM MgCl2, and 2 mM EDTA.

[0047] S3 utilizes a nonlinear hybridization chain reaction for sensing and detection:

[0048] The activated Y-DNA probe from step S2 was used to modify the electrode surface prepared in step S1. After washing with Tris-HCl buffer, unbound active sites were blocked with MEA solution. After washing, miRNA-25 was added for incubation. After washing, the electrode was immersed in a solution containing hybridization substrate for incubation. Specifically, well-dispersed Ce-ZnIn2S4 containing 1 wt% PAMAM was dripped onto the FTO electrode and dried at 37°C for 1 h to prepare the Ce-ZnIn2S4 gate. Then, Y-DNA activated with 5 mg / mL EDC / NHS crosslinking agent was modified onto the Ce-ZnIn2S4 gate surface and incubated at 4°C for 1 h to fix the Y-DNA. Then, unbound active sites on the gate were blocked with 1 mM MEA solution and incubated at 4°C for 1 h. Then, it was incubated with different concentrations of miRNA-25 or interfering substances at 35°C for 120 min, and then incubated with nHCR components at a concentration of 40 nM for 3 h at 37°C. Wash with washing buffer after each modification.

[0049] The Ce-ZnIn2S4 sensor was used to test in a 0.05M TEOA solution containing 0.1M PBS, and the results are as follows: Figure 5 This demonstrates that the Ce-ZnIn2S4 sensor has good stability.

[0050] Ce-ZnIn2S4 sensor applied to the detection of miRNA-25

[0051] The above photoelectric sensor was evaluated using miRNA-25 (1 fM to 1 nM):

[0052] Following step S3, the prepared gate electrode is subjected to OPECT testing in an electrolyte solution. Each experiment must be performed in triplicate. The test results are shown below. Figure 6-8 : Figure 6 This indicates that as the concentration of miRNA-25 decreases, the sensor signal gradually decreases. Figure 7 The study showed a linear relationship between changes in photoelectric signal values ​​and miRNA-25 concentration, with the linear regression equation being: ΔI / ΔI0=-0.13LogC-1.06(R) 2 =0.9975); Figure 8 This is a selective test of the detection system using the sensor prepared in the example: Figure 8 The values ​​are miRNA-17 / -21 / -10b / -145 / -155 / -25. The ordinate with -25 is the smallest, indicating that this sensor has good specificity. The results show that miRNA-25 has good specificity.

[0053] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing a MOF derivative organic photoelectrochemical transistor sensor, characterized in that the steps of The application relates to a sensor for detecting miRNA-25. The application comprises the following steps: S1, preparing a MOF derivative Ce-ZnIn2S4: A tetradecahedral Ce-MOF is prepared by a solvothermal method, the Ce-MOF is derived into Ce-ZnIn2S4 by a one-pot method, the Ce-ZnIn2S4 is modified on fluorine-doped SnO2 conductive glass by a polyamidoamine dendrimer PAMAM, and a Ce-ZnIn2S4 gate is prepared; S2, preparing a Y-DNA probe and a double-stranded substrate: The Y-DNA probe is prepared by mixing three single-strand DNAs in equal molar amounts, annealing, naturally cooling and storing at a low temperature; and the double-stranded substrate is prepared by the same method as the Y-DNA probe except that the corresponding single-strand sequence is not used. S3, sensing and detecting by a nonlinear hybridization chain reaction nHCR:

2. The production method according to claim 1, characterized by, The Y-DNA probe in step S2 after activation is modified on the gate prepared in step S1, single ethanol amine solution is used to block the unbound active sites after Tris-HCl buffer washing, miRNA-25 is added for incubation after washing, and the gate is immersed in a solution containing a hybridization substrate for incubation. In step S1, when the Ce-ZnIn2S4 sensor is prepared, the specific steps comprise the following steps: S101, 5.1 mmol of acetic acid, 3.5 mmol of NaClO4.H2O and 100 mg of polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol F127 are mixed into 6 mL of deionized water to obtain a uniform solution, S102, 167 mM (NH4)2Ce(NO3)6 and 167 mM terephthalic acid are added into the uniform solution, heating treatment is conducted in a water bath, after the reaction is completed, the precipitated Ce-MOF is collected, and the Ce-MOF is sequentially washed by distilled water, DMF and ethanol and vacuum dried, 3. The preparation method according to claim 1, characterized in that, S103, the dried Ce-MOF is dispersed into 10 mL of a mixture of deionized water and glycerol with a volume ratio of 4:1, the mixture is uniformly stirred, then 40 mM InCl3.4H2O, 20 mM ZnCl2 and 80 mM thioacetamide are added into the mixture, heating treatment is conducted in an oil bath, the obtained precipitate is collected, washed by ethanol and vacuum dried.

4. The method of claim 1, wherein, In step S1, the concentration of the PAMAM is 1 wt%.

5. The preparation method according to claim 4, characterized in that, In step S2, three single-strand DNAs dissolved in a hybridization buffer are mixed, annealed at 95 DEG C for 5 min, and Y-DNA is prepared, and the Y-DNA is naturally cooled to room temperature and stored at 4 DEG C for standby, and the double-strand substrate sequence is prepared by the same method except that the corresponding single-strand sequence is not used.

6. The method of claim 1, wherein, In step S2, the hybridization buffer is configured by 40 mM Tris-HCl, 10 mM MgCl2 and 2 mM EDTA. The specific steps of step S3 are as follows: S301, the well-dispersed Ce-ZnIn2S4 containing 1 wt% PAMAM is dropped onto the conductive glass electrode, dried at 37 DEG C for 1 h, and a Ce-ZnIn2S4 gate is prepared, S302, Y-DNA activated by EDC / NHS cross-linking agent was modified on the surface of Ce-ZnIn2S4 gate, 4°C incubation for 1 h to fix Y-DNA, S303, ethanolamine MEA solution was used to block the unbound active sites of the gate, 4°C incubation for 1 h, S304, incubation with different concentrations of miRNA-25 or interfering substances as target detection molecules at 35°C for 120 min, then incubation with nHCR components at 37°C for 3 h, washing with washing buffer after each modification.

7. The production method according to claim 6, wherein In step S3, the activated Y-DNA was mixed with 5 mg / mL EDC / NHS solution, and incubated at 4°C for 1 h.

8. The preparation method according to claim 6, characterized in that, In step S3, the miRNA-25 was dissolved in the competition buffer, which was prepared by 1 mM Tris-HCl, 25 mM NaCl, 1 mM ethylenediaminetetraacetic acid EDTA.

9. The preparation method according to claim 6, characterized in that, In step S3, the blocking buffer was 1 mM ethanolamine.

10. Application of the MOF derivative organic photoelectrochemical transistor biosensor prepared by the method of any one of claims 1-9 in detection of miRNA-25.

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