Microbial electrochemical transistor for BOD (Biochemical Oxygen Demand) detection and detection system

Abstract

The invention relates to a microbial electrochemical transistor for BOD (Biochemical Oxygen Demand) detection and a detection system, and belongs to the technical field of biochemical analysis. The microbial electrochemical transistor comprises a source electrode, a grid electrode, a drain electrode and an organic semiconductor material, and the source electrode and the drain electrode are connected through the organic semiconductor material to form a semiconductor channel. And microorganisms grow at the gate electrode. Wherein a catalyst with hydrogen evolution reaction catalytic activity is introduced into the microbial electrochemical transistor and is used for consuming electrons generated by microorganisms. The microbial electrochemical transistor is packaged in a micro-fluidic chip, and is combined with a signal acquisition module and an upper computer to form a BOD (Biochemical Oxygen Demand) detection system, so that the rapid detection of BOD and the miniaturization of detection equipment can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of biochemical analysis and relates to a microbial electrochemical transistor and a detection system for BOD detection. Background Art

[0002] Biochemical analysis technology is a technology that uses chemical reactions to detect and analyze biological molecules or organisms. Among them, biochemical oxygen demand (BOD) refers to the amount of dissolved oxygen consumed by aerobic microorganisms when decomposing organic matter under certain conditions. It is an important indicator for evaluating the degree of water pollution.

[0003] Traditional BOD detection methods include BOD5, microbial membrane electrode, and BODQ. Among them, BOD5 is a classic BOD detection method, which calculates the BOD value by measuring the amount of dissolved oxygen consumed by aerobic microorganisms within 5 days at a certain temperature. Although this method is accurate, it requires a long detection time. Microbial membrane electrode is an electrochemical sensor based on microorganisms, which can detect the BOD value by measuring the difference in dissolved oxygen produced before and after the water sample to be tested passes through the microbial membrane electrode. This method can realize real-time BOD detection, but the error is large and it is easily affected by environmental factors. BODQ is a BOD detection method based on microbial fuel cells, which can detect the BOD value by measuring the coulomb amount produced by electroactive microorganisms in microbial fuel cells. Although this method can realize rapid BOD detection, it is limited by the volume of microbial fuel cells and cannot be miniaturized. It can be seen that although the traditional BOD detection method can measure the BOD value more accurately, it has some disadvantages, such as long detection time, large error, and inability to be miniaturized.

[0004] Organic electrochemical transistor (OECT) is based on the principle of field effect signal amplification, and has the characteristics of low power consumption, high sensitivity, and integration, and is widely used in the detection of glucose, protein, DNA, and RNA. OECT can greatly amplify electrical signals, but when OECT is applied to BOD detection, there is no electrode to consume the electrons generated by microorganisms at the gate. Therefore, the existing OECT devices cannot achieve online enrichment and stable operation of electroactive microorganisms, and thus cannot achieve rapid online detection of BOD and miniaturization of detection equipment. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a microbial electrochemical transistor and detection system for BOD detection. By introducing a catalyst that consumes electrons at the source and drain of the OECT, the online enrichment and stable operation of electroactive microorganisms can be achieved, thereby realizing rapid online detection of BOD and miniaturization of the detection equipment.

[0006] To achieve the above object, the present invention provides a microbial electrochemical transistor for BOD detection, which includes a source electrode, a gate electrode, a drain electrode, and an organic semiconductor material, wherein the source electrode and the drain electrode are connected to form a semiconductor channel through the organic semiconductor material. Microorganisms grow at the gate electrode. The source electrode and the drain electrode are electrodes having catalytic activity for hydrogen evolution reaction, and are used to consume electrons generated by the microorganisms.

[0007] In other embodiments of the present invention, in order to consume the electrons generated by the microorganisms, a secondary source electrode may be provided at the source electrode, and the secondary source electrode is an electrode having catalytic activity for hydrogen evolution reaction.

[0008] In other embodiments of the present invention, in order to consume the electrons generated by the microorganisms, a catalyst having catalytic activity for hydrogen evolution reaction may be doped into the semiconductor channel.

[0009] On the other hand, the present invention provides a system for BOD detection, which includes a microfluidic chip, a signal acquisition module and a host computer.

[0010] Among them, a microbial electrochemical transistor is encapsulated in the microfluidic chip, and the microbial electrochemical transistor includes a source electrode, a gate electrode, and a drain electrode, and an organic semiconductor material. The source electrode and the drain electrode are connected through the organic semiconductor material to form a semiconductor channel. Microorganisms grow at the gate electrode of the transistor. A material with catalytic activity for hydrogen evolution reaction is set in the microbial electrochemical transistor to consume the electrons generated by the microorganisms.

[0011] The signal acquisition module is used to acquire the electrical signal between the source and the drain, and at the same time acquire the electrical signal between the gate and the source.

[0012] The host computer receives the signal transmitted by the signal acquisition module and performs calculation to realize BOD detection.

[0013] In one embodiment of the present invention, the material having catalytic activity for hydrogen evolution reaction is provided in the microbial electrochemical transistor. Specifically, the source and drain electrodes in the microbial electrochemical transistor are electrodes having catalytic activity for hydrogen evolution reaction, which are used to consume electrons generated by microorganisms.

[0014] In one embodiment of the present invention, the material having catalytic activity for hydrogen evolution reaction is provided in the microbial electrochemical transistor. Specifically, a sub-source electrode is provided at the source of the microbial electrochemical transistor. The sub-source electrode is an electrode having catalytic activity for hydrogen evolution reaction and is used to consume electrons generated by microorganisms.

[0015] In one embodiment of the present invention, the material having catalytic activity for hydrogen evolution reaction is provided in the microbial electrochemical transistor. Specifically, a catalyst having catalytic activity for hydrogen evolution reaction is doped in the semiconductor channel of the microbial electrochemical transistor to consume electrons generated by the microorganisms.

[0016] The beneficial effect of the present invention is that the present invention realizes the online enrichment and stable operation of electroactive microorganisms by introducing a catalyst that consumes electrons into the OECT, thereby realizing the rapid online detection of BOD and the miniaturization of the detection equipment.

[0017] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0019] Figure 1 An integrated microbial electrochemical transistor provided by one embodiment of the present invention;

[0020] Figure 2 A split microbial electrochemical transistor provided by an embodiment of the present invention;

[0021] Figure 3 A doped microbial electrochemical transistor provided by one embodiment of the present invention;

[0022] Figure 4 A microfluidic chip based on an integrated microbial electrochemical transistor provided in one embodiment of the present invention;

[0023] Figure 5 for Figure 4 The electrode morphology and element distribution of the chip shown. Figure 5 (a) is the distribution of microorganisms on the gate. Figure 5 (b) and (c) are the microstructure and element distribution of the bare Pt interdigital electrode, respectively. Figure 5 (d) and (e) are the microstructure and element distribution of Pt interdigital electrodes spin-coated with PEDOT, respectively;

[0024] Figure 6 (a) is the current response curve of the microfluidic chip under batch injection of sodium acetate solutions with different concentrations. Figure 6 (b) is the linear fit of the response curve. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0026] In order to solve the problem that the OECT device cannot operate stably for a long time because the microbial electrical signals have no electrodes to consume the electrons generated by the microorganisms, the present invention proposes to introduce a catalyst that can consume electrons into the source and drain of the OECT device, thereby achieving online enrichment and stable operation of electroactive microorganisms.

[0027] When BOD is detected by OECT devices, microorganisms are generally grown on the gate, and the gate material can be gold, gold surface loaded with PEDOT, gold surface loaded with hydrophilic modified PEDOT, carbon cloth, carbon paper, carbon felt, etc. Microorganisms are continuously cultured and inoculated at a certain voltage through bacterial liquids such as anaerobic activated sludge, microbial fuel cells, and microbial electrolysis cells until the current output signal is stable.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment provides an integrated microbial electrochemical transistor, by replacing the gold source and drain of the traditional OECT device with Pt electrodes and Ni electrodes having catalytic activity for hydrogen evolution reaction. The added catalytic electrode promotes the occurrence of hydrogen evolution reaction, consumes the electrons generated by the microorganisms, and maintains the continuous growth and training of the microorganisms on the gate (microbial electrode).

[0030] Example 2

[0031] like Figure 2 As shown, a split microbial electrochemical transistor provided in this embodiment is added with a catalytically active Pt electrode, Ni electrode, Pt / C electrode, metal oxide electrode, and single-atom catalyst electrode as the second source electrode on the basis of the original OECT device structure. The added catalytic electrode promotes the hydrogen evolution reaction and consumes the electrons generated by the microorganisms to maintain the continuous growth and training of the microorganisms on the gate (microbial electrode).

[0032] Example 3

[0033] like Figure 3As shown, this embodiment provides a doped microbial electrochemical transistor. On the basis of the original OECT device, a powdered catalyst such as a Pt / C catalyst, a metal oxide catalyst, a single atom catalyst, etc. with catalytic activity is doped in the semiconductor channel of the device. The added catalyst promotes the hydrogen evolution reaction and consumes the electrons generated by the microorganisms to maintain the continuous growth and training of the microorganisms on the gate (microbial electrode).

[0034] Example 4

[0035] This embodiment provides a microfluidic chip based on an integrated microbial electrochemical transistor, which is obtained by encapsulating an integrated microbial electrochemical transistor in a microfluidic chip of a certain volume, wherein the gate of the transistor can be distributed in the same plane as the source and drain, or can be distributed opposite to each other. The chip operates at a certain voltage, and organic solutions of different concentrations are introduced into the microfluidic chip. The activity of the microorganisms changes with the change in the concentration of the organic matter, thereby realizing the collection and amplification of the extracellular electronic signals of the microorganisms, and the monitoring of the organic matter concentration. Figure 4 The microfluidic chip based on the integrated microbial electrochemical transistor provided in this embodiment is shown, wherein the gate of the transistor is opposite to the source and drain, and the source and drain are micro-nano processed Pt interdigital electrodes, and the substrate is SiO2.

[0036] This embodiment uses sodium acetate solutions of different concentrations to monitor the current signal. The inoculation of microorganisms is completed by placing carbon treated with oxygen plasma hydrophilicity in the microbial fuel cell for one week in advance.

[0037] Figure 5 (a) shows the distribution of microorganisms on the transistor gate. It can be seen that the microorganisms are successfully inoculated on the gate carbon cloth. Figure 5 (b) and (c) are the microstructure and element distribution of the bare Pt interdigital electrode, respectively. Figure 5 (d) and (e) are the microstructure and element distribution of the Pt interdigital electrode spin-coated with PEDOT, respectively. It can be seen that the PEDOT film is evenly loaded on the electrode surface without peeling off.

[0038] Figure 6 (a) shows the current signal response of sodium acetate solutions of different concentrations when the packaged microfluidic chip is batch-injected, where the gate-source voltage V GS is 1.2V, drain-source voltage V DS The injection voltage is 0.6V, the injection interval is 30min, the injection speed is 500μL / min, and the injection volume is 1mL. Figure 6 (b) It can be seen that during batch injection, the difference between the initial value and the maximum value of the current response ΔI DS At a sodium acetate concentration of 10 mg / L-1 When the concentration increases, R 2 It is 0.994.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A microbial electrochemical transistor for BOD detection, comprising a source electrode, a gate electrode, a drain electrode, and an organic semiconductor material, wherein the source electrode and the drain electrode are connected through the organic semiconductor material to form a semiconductor channel; microorganisms grow at the gate electrode; characterized in that: The source electrode and the drain electrode are electrodes having catalytic activity for hydrogen evolution reaction and are used to consume the electrons generated by the microorganisms.

2. A microbial electrochemical transistor for BOD detection, comprising a source electrode, a gate electrode, a drain electrode, and an organic semiconductor material, wherein the source electrode and the drain electrode are connected through the organic semiconductor material to form a semiconductor channel; microorganisms grow at the gate electrode; characterized in that: It also includes a secondary source electrode, which is an electrode with catalytic activity for hydrogen evolution reaction and is used to consume electrons generated by microorganisms.

3. A microbial electrochemical transistor for BOD detection, comprising a source electrode, a gate electrode, and a drain electrode, and an organic semiconductor material, wherein the source electrode and the drain electrode are connected through the organic semiconductor material to form a semiconductor channel; microorganisms grow at the gate electrode; characterized in that: The semiconductor channel is doped with a catalyst having catalytic activity for hydrogen evolution reaction, which is used to consume electrons generated by microorganisms.

4. A system for BOD detection, characterized in that: Including microfluidic chip, signal acquisition module and host computer; The microfluidic chip is encapsulated with a microbial electrochemical transistor; the microbial electrochemical transistor comprises a source electrode, a gate electrode, a drain electrode, and an organic semiconductor material, the source electrode and the drain electrode are connected through the organic semiconductor material to form a semiconductor channel; microorganisms grow at the gate electrode; a material having a catalytic activity for hydrogen evolution reaction is arranged in the microbial electrochemical transistor to consume electrons generated by the microorganisms; The signal acquisition module is used to acquire the electrical signal between the source and the drain, and at the same time acquire the electrical signal between the gate and the source; The host computer receives the signal transmitted by the signal acquisition module and performs calculation to realize BOD detection.

5. A system for BOD detection according to claim 4, characterized in that: The microbial electrochemical transistor is provided with a material having catalytic activity for hydrogen evolution reaction. Specifically, the source and drain electrodes in the microbial electrochemical transistor are electrodes having catalytic activity for hydrogen evolution reaction, which are used to consume electrons generated by microorganisms.

6. A system for BOD detection according to claim 4, characterized in that: The microbial electrochemical transistor is provided with a material having catalytic activity for hydrogen evolution reaction. Specifically, the microbial electrochemical transistor is provided with a secondary source electrode, which is an electrode having catalytic activity for hydrogen evolution reaction and is used to consume electrons generated by microorganisms.

7. A system for BOD detection according to claim 4, characterized in that: The microbial electrochemical transistor is provided with a material having catalytic activity for hydrogen evolution reaction. Specifically, a catalyst having catalytic activity for hydrogen evolution reaction is doped in a semiconductor channel of the microbial electrochemical transistor to consume electrons generated by the microorganisms.

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