Electrochemical triode biosensor and preparation method thereof

Abstract

The present invention discloses an electrochemical triode biosensor and a preparation method thereof. The electrochemical triode biosensor of the present invention comprises a conductive cavity and a detection cavity which are independent of each other and can realize electrical connection for detection; the conductive cavity and the detection cavity are independently separated from each other, and after each detection, only the detection cavity part is contaminated, the detection cavity part is disposable and can be discarded, and the entire conductive cavity part is not contaminated and can still be reused, thereby making the use of the overall electrochemical triode biosensor more economical. In addition, since the electrolyte in the conductive cavity part is not restricted during the detection process, it has high transconductance and biocompatibility, and still has high sensitivity during repeated use, and is more economical. The preparation method of the present invention can realize the rapid preparation of the electrochemical triode biosensor, thereby realizing large-scale production of the electrochemical triode biosensor of the present invention.

Description

Technical Field

[0001] The present invention relates to the technical field of biological and medical detection equipment, and in particular to an electrochemical triode biosensor and a preparation method thereof. Background Art

[0002] The biological / medical electrochemical triode sensor is a device that uses electrochemical principles to measure viruses, lesions, biological molecules, etc. Electrochemical triode sensors have been widely studied and have a variety of design schemes.

[0003] The common electrochemical triode sensor at present is that the source / drain electrode, active layer and gate of the electrochemical triode are all immersed in the same electrolyte (PBS) cavity, and all parts need to be discarded for one-time use. However, the processing cost of the conductive part (active layer and source / drain electrode) of the high-precision sensor is not necessarily low, and the sensitivity of the PBS electrolyte device is limited, which is mainly limited by the ion concentration and type in the PBS. At the same time, it is difficult to have both biocompatibility and high transconductance of the entire device. Summary of the invention

[0004] In order to solve the problems that the existing electrochemical triode sensors are seriously wasted due to one-time use and it is difficult for the entire sensor to have both biocompatibility and high transconductance, the present invention provides an electrochemical triode biosensor, specifically an electrochemical triode biosensor that can be used locally and once, has good biocompatibility and high transconductance.

[0005] The present invention also aims to provide a method for preparing the electrochemical triode biosensor described above.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] An electrochemical triode biosensor comprises a detection cavity and a conduction cavity;

[0008] The detection cavity and the conduction cavity are independent and separated from each other, and a detection electrical connection can be achieved between the detection cavity and the conduction cavity.

[0009] In a preferred embodiment, the detection cavity includes a gate electrode and a first connecting electrode;

[0010] The gate electrode and the first connecting electrode are independently arranged and are partially immersed in the electrolyte I.

[0011] In a more preferred embodiment, a first connection lead-out terminal is provided on an exposed portion of the first connection electrode that is not immersed in the electrolyte I.

[0012] Further preferably, the first connection lead-out terminal is designed as a lead-out connection terminal that is easy to connect and disconnect, including a snap, a plug, a jack or a clamp.

[0013] In a more preferred embodiment, a gate treatment layer is provided on the portion of the gate electrode that can be immersed in the electrolyte I. By providing the gate treatment layer on the surface of the gate electrode, a larger surface area and catalytic properties can be obtained.

[0014] In a more preferred embodiment, the gate electrode is a conductor material, a semiconductor material, a thin film material, a nano material or a porous material, and the material includes metal, conductive oxide, conductive polymer, semiconductor, graphite or graphene.

[0015] Furthermore, the metal includes Pt (platinum), Au (gold) or Ag (silver).

[0016] In a more preferred embodiment, the material of the first connecting electrode includes Au (gold) or Ag (silver).

[0017] In a more preferred embodiment, the electrolyte I is a biocompatible electrolyte, including a phosphate-buffered saline solution (PBS) or an aqueous solution, and its components include additives such as enzymes, antibodies, and nanoprobes.

[0018] In a more preferred embodiment, in the electrochemical triode biosensor described in any of the above items, the gate electrode and the first connecting electrode are both formed on a first substrate; a detection container is buckled on the first substrate; the detection container is buckled on the first substrate and partially covers the gate electrode and the first connecting electrode; and the electrolyte I is contained in the detection container.

[0019] In a more preferred embodiment, the first substrate is a rigid material or a flexible material, and the material includes glass, ceramic, paper or plastic, and further preferably includes polyimide (Polyimade), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

[0020] In a preferred embodiment, the conductive cavity comprises a source electrode, a drain electrode and a second connecting electrode;

[0021] The source electrode, the drain electrode and the second connection electrode are independently arranged and partially immersed in the electrolyte II; a triode active layer is arranged between the source electrode and the drain electrode, and the triode active layer is immersed in the electrolyte II.

[0022] In a more preferred embodiment, a second connection lead-out terminal is provided on the exposed portion of the second connection electrode that is not immersed in the electrolyte II.

[0023] Further preferably, the second connection lead-out terminal is designed as a lead-out connection terminal that is easy to connect and disconnect, including a snap, a plug, a jack or a clamp.

[0024] In a more preferred embodiment, the material of the second connecting electrode includes Au (gold) or Ag (silver).

[0025] In a more preferred embodiment, the transistor active layer is an organic electrochemical transistor or an inorganic electrochemical transistor, and the active material includes a polymer or small molecule organic conductor, an organic semiconductor, an inorganic conductor or an inorganic semiconductor.

[0026] In a more preferred embodiment, the electrolyte II is an electrolyte that can achieve high transconductance of the transistor, including organic salt solutions and inorganic salt solutions of various concentrations, which can be in the form of colloid or solid, including NaCl aqueous solution, KCl aqueous solution, and phosphate buffer solution (PBS).

[0027] In a more preferred embodiment, in the electrochemical triode biosensor described in any of the above items, the source electrode, the drain electrode and the second connecting electrode are all formed on a second substrate; a conductive container is buckled on the second substrate; the conductive container is buckled on the second substrate and partially covers the source electrode, the drain electrode and the second connecting electrode, and completely covers the triode active layer; the electrolyte II is poured into the conductive container.

[0028] In a more preferred embodiment, the second substrate is a rigid material or a flexible material, and the material includes glass, ceramic, paper or plastic, and further preferably includes polyimide (Polyimade), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

[0029] In a preferred embodiment, an electrical connection switch capable of realizing electrical connection on and off is provided between the conduction cavity and the detection cavity.

[0030] A method for preparing an electrochemical triode biosensor comprises the following steps:

[0031] S1, depositing and processing a gate electrode and a first connecting electrode on a first substrate; processing a local surface of the gate electrode to form a gate processing layer; processing a first connecting lead-out terminal on the first connecting electrode;

[0032] S2, bonding a detection container and the first substrate, so that the detection container partially covers the gate electrode and the first connecting electrode, and completely covers the gate processing layer, and the first connecting lead-out terminal is exposed outside the detection container, to obtain a detection cavity;

[0033] S3, depositing and processing a mutually independent source electrode, a drain electrode and a second connecting electrode on the second substrate, depositing and processing a transistor active layer between the source electrode and the drain electrode; processing a second connecting lead-out terminal on the second connecting electrode;

[0034] S4, bonding the conductive container to the second substrate, and making the conductive container partially cover the source electrode, the drain electrode and the second connecting electrode, and completely cover the active layer of the transistor, with the second connecting lead-out terminal exposed outside the conductive container; pouring electrolyte II into the conductive container, sealing it, and obtaining a conductive cavity;

[0035] S5. An electrical connection switch is provided between the first connection lead-out terminal and the second connection lead-out terminal to obtain the electrochemical triode biosensor.

[0036] In a preferred embodiment, in S1, a micro / nanostructured material is attached to the gate electrode by nanoparticle coating, 3D printing or electrospinning to process a local surface of the gate electrode, thereby forming a gate processing layer.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] The electrochemical triode biosensor of the present invention is specifically an electrochemical biosensor for local one-time application. The conduction cavity and the detection cavity are independently separated from each other. After each detection, only the detection cavity part is contaminated. The detection cavity part is used once and can be discarded, while the entire conduction cavity part is not contaminated and can still be reused, thereby making the use of the overall electrochemical triode biosensor more economical.

[0039] In addition, since the electrolyte in the conductive cavity part is not restricted during the detection process, it has high transconductance and biocompatibility, and still has high sensitivity during repeated use, which is more economical.

[0040] The preparation method of the present invention can realize the rapid preparation of the electrochemical biosensor for local one-time application, thereby realizing the large-scale preparation and production of the electrochemical triode biosensor of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic cross-sectional view of the electrochemical triode biosensor of the present invention in a specific embodiment;

[0042] Figure 2 It is a schematic diagram of the top view structure of the conduction cavity;

[0043] Figure 3It is a schematic diagram of the structure of the electrochemical triode biosensor of the present invention performing detection work in a specific embodiment;

[0044] Figure markings: 1-detection cavity, 11-first substrate, 12-detection container, 13-gate electrode, 14-first connecting electrode, 141-first connecting lead-out terminal, 15-gate electrode processing layer, 16-electrolyte I, 2-conductive cavity, 21-second substrate, 22-conductive container, 23-source electrode, 24-drain electrode, 25-second connecting electrode, 251-second connecting lead-out terminal, 26-transistor active layer, 27-electrolyte II, 3-electrically connected switch. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope and implementation mode of the present invention are not limited thereto. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0046] Furthermore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0047] The electrochemical triode biosensor of the present invention is shown in Figure 1 As shown, it includes a detection cavity 1 and a conduction cavity 2. Specifically, the detection cavity 1 is the main part of the detection, and the conduction cavity 2 can provide a triode conduction function; during the detection operation, a triode high-transistor conductive connection is formed between the detection cavity 1 and the conduction cavity 2. When the effective gate voltage of the detection cavity 1 changes, the active layer current of the conduction cavity 2 will change, thereby realizing the output of the detection signal and obtaining the detection result.

[0048] The detection cavity 1 and the conductive cavity 2 are separated from each other, and the detection cavity 1 and the conductive cavity 2 can be electrically connected for detection. That is, the detection cavity 1 and the conductive cavity 2 are independent integral parts and do not interfere with each other. The detection cavity 1 and the conductive cavity 2 are both independently replaceable. When used for detection, the detection cavity 1 and the conductive cavity 2 can be used in combination, and a complete detection work can be performed after the electrical connection is achieved.

[0049] exist Figure 1In the specific embodiment shown, based on the fact that the detection object environmental liquid is mainly added into the detection cavity 1 during the detection process, different detection object environmental liquids need to use a new detection cavity 1 accordingly, so the detection cavity 1 is designed to be replaceable, and the conductive cavity 2 can be reused multiple times. In this way, after each detection, only the detection cavity 1 is contaminated, the detection cavity 1 is used once and can be discarded, and the entire conductive cavity 2 is not contaminated and can still be reused, so that the use of the overall electrochemical triode biosensor is more economical.

[0050] Please see again Figure 1 As shown, in a preferred embodiment, the detection cavity 1 includes a gate electrode 13 and a first connecting electrode 14. Optionally, the gate electrode 13 is a conductor material, a semiconductor material, a thin film material, a nano material or a porous material, and the material includes metal, conductive oxide, conductive polymer, semiconductor, graphite or graphene; further, the metal includes Pt (platinum), Au (gold) or Ag (silver). The material of the first connecting electrode 14 includes Au (gold) or Ag (silver), and Cr is selected as the bonding layer. For example, in a specific optional embodiment, the gate electrode 13 is Pt with a thickness of 100nm, the first connecting electrode 14 is Au with a thickness of 100nm, and the width of the gate electrode 13 and the first connecting electrode 14 are both 2mm, and the length is both 10mm.

[0051] The gate electrode 13 and the first connection electrode 14 are independently arranged and partially immersed in the electrolyte 116. In an optional embodiment, the electrolyte 116 is a biocompatible electrolyte, including a phosphate solution (PBS) or an aqueous solution, and the components include enzymes, antibodies, nanoprobes and other additives.

[0052] In addition, a gate treatment layer 15 is provided on the portion of the gate electrode 13 that can be immersed in the electrolyte 116. By providing the gate treatment layer 15 on the surface of the gate electrode 13, a larger surface area and catalytic properties can be obtained.

[0053] Specifically, the gate electrode 13 and the first connection electrode 14 independently provided from each other can be provided in a discrete manner or independently provided on the substrate. Figure 1 As shown, in the specific embodiment shown, the gate electrode 13 and the first connecting electrode 14 are both formed on the first substrate 11. In an optional embodiment, the first substrate 11 is a rigid material or a flexible material, and the material includes glass, ceramic, paper or plastic, and further preferably includes SiO2 / Si glass, Polyimade, PMMA, PET or PEN.

[0054] In addition, a detection container 12 is buckled on the first substrate 11; moreover, the detection container 12 is buckled on the first substrate 11 and partially covers the gate electrode 13 and the first connecting electrode 14, and the electrolyte 116 is contained in the detection container 12, so that the gate electrode 13 and the first connecting electrode 14 are partially immersed in the electrolyte 116 and partially exposed outside the detection container 12. Optionally, the shape and structure of the detection container 12 can be designed as required, such as in a specific optional embodiment, the detection container 12 is designed as a cylindrical structure with a diameter and a height of 1 cm.

[0055] Further, a first connection lead-out terminal 141 is provided on the exposed portion of the first connection electrode 14 that is not immersed in the electrolyte 116. Preferably, the first connection lead-out terminal 141 is designed as a lead-out connection terminal that is easy to connect and disconnect, including a snap, a plug, a jack or a clamp. By setting the first connection lead-out terminal 141, a control component that enables the first connection electrode 14 and the conductive cavity 2 to be quickly turned on and off can be further provided, including an on-off switch, etc.

[0056] See also Figure 1 As shown, in a preferred embodiment, the conductive cavity 2 includes a source electrode 23, a drain electrode 24 and a second connection electrode 25. In an optional embodiment, the material of the second connection electrode 25 includes Au (gold) or Ag (silver), and Cr is selected as the bonding layer.

[0057] The source electrode 23, the drain electrode 24 and the second connection electrode 25 are independently arranged and partially immersed in the electrolyte II 27; and, see Figure 1 and Figure 2 As shown, a transistor active layer 26 is disposed between the source electrode 23 and the drain electrode 24 , and the transistor active layer 26 is immersed in the electrolyte II 27 .

[0058] In an optional embodiment, the transistor active layer 26 is an organic electrochemical transistor or an inorganic electrochemical transistor, and the active material includes a polymer or small molecule organic conductor, an organic semiconductor, an inorganic conductor or an inorganic semiconductor; in a specific embodiment, the material of the transistor active layer 26 is PEDOT-PSS (polymer of poly 3,4-ethylenedioxythiophene and polystyrene sulfonate); the thickness of the transistor active layer 26 is set according to the actual detection requirements, such as the designed thickness is 100 nanometers. The electrolyte II 27 is any electrolyte that can achieve high transconductance of the transistor, including organic salt solutions and inorganic salt solutions of various concentrations, and the form can be colloid or solid, including NaCl aqueous solution, KCl aqueous solution, phosphate buffer solution (PBS).

[0059] Specifically, the mutually independent source electrode 23, drain electrode 24 and second connection electrode 25 can be set separately or independently on the substrate. Figure 1 As shown, in the specific embodiment shown, the source electrode 23, the drain electrode 24 and the second connecting electrode 25 are all formed on the second substrate 21; in a more preferred embodiment, the second substrate 21 is a rigid material or a flexible material, and the material includes glass, ceramic, paper or plastic, and further preferably includes Polyimade, PMMA, PET or PEN.

[0060] As in a specific optional embodiment, the source electrode 23, the drain electrode 24 and the second connecting electrode 25 are all 2 mm wide and 10 mm long, wherein the channel width between the source electrode and the drain electrode is 100 μm; and the source electrode 23, the drain electrode 24 and the second connecting electrode 25 are all 100 nm Au.

[0061] In addition, a conductive container 22 is buckled on the second substrate 21; the conductive container 22 is buckled on the second substrate 21 and partially covers the source electrode 23, the drain electrode 24 and the second connection electrode 25, and completely covers the triode active layer 26; the electrolyte II 27 is poured into the conductive container 22. After the electrolyte II 27 is injected into the conductive container 22, the top of the conductive container 22 is closed to form a sealed integral container.

[0062] Optionally, the shape and structure of the conductive container 22 can be designed as required. For example, in a specific optional embodiment, the conductive container 22 is designed to be a cylindrical structure with a diameter and a height of 1 cm.

[0063] Further, a second connection lead-out terminal 251 is provided on the exposed portion of the second connection electrode 25 that is not immersed in the electrolyte II 27. Preferably, the second connection lead-out terminal 252 is designed as a lead-out connection terminal that is easy to connect and disconnect, including a snap, a plug, a jack or a clamp. By setting the second connection lead-out terminal 151, a control component that enables the second connection electrode 15 and the detection cavity 1 to be quickly turned on and off can be further provided, including an on-off switch, etc.

[0064] Please see again Figure 1 As shown, in a preferred embodiment, an electrical connection switch 3 for realizing electrical connection on and off is provided between the conduction cavity 2 and the detection cavity 1. Specifically, one end of the electrical connection switch 3 is movably connected to the first connection lead-out terminal 141 or the second connection lead-out terminal 151, and the other end is connected to the second connection lead-out terminal 151 or the first connection lead-out terminal 141 to realize on and off connection; Figure 1In the embodiment specifically shown, one end of the electrical connection switch 3 is movably connected to the first connection lead-out terminal 141, and the other end is connected to the second connection lead-out terminal 151 to achieve on-off connection, thereby realizing rapid on-off control of the detection cavity 1 and the conduction cavity 2.

[0065] Example 1

[0066] The above electrochemical triode biosensor is used for glucose detection. Specifically, the electrolyte I16 used is PBS + glucose oxidase (PBS solution of glucose oxidase), the electrolyte II27 used is 1M KCl aqueous solution, and the Figure 3 The connection method shown connects the detection cavity 1 and the conduction cavity 2.

[0067] Among them, two voltage signals are provided by two Keithley 2400 source meters, so that a bias voltage is formed between the source electrode 23 and the gate electrode 13, and one of the source meters is used to measure the current flowing through the transistor active layer 26, and the change of the current over time is monitored by PC through Matlab software. A certain amount of glucose PBS solution is dripped into the detection cavity 1 in an orderly manner. When a significant current change is found, the concentration of glucose in the detection cavity 1 is calculated to obtain the glucose detection accuracy of the device. The measurement accuracy of the obtained device is 10 -10 M, the corresponding current change is 5μA (the noise fluctuation of the measurement system is about 1μA).

[0068] Since the detection cavity 1 and the conduction cavity 2 are independent of each other and are only connected by the electrical connection switch 3, after the detection is completed, the detection cavity 1 can be discarded, while the conduction cavity 2 can be reused.

[0069] In addition, the present invention also provides a method for preparing the electrochemical triode biosensor described above.

[0070] The preparation method of the electrochemical triode biosensor of the present invention comprises the following steps:

[0071] S1, depositing and processing a gate electrode 13 and a first connecting electrode 14 on a first substrate 11 through a mask; processing a local surface of the gate electrode 13 to form a gate processing layer 15; processing a first connecting lead-out terminal 141 on the first connecting electrode 14;

[0072] In a preferred embodiment, a micro / nanostructured material is attached to the gate electrode by nanoparticle coating, 3D printing or electrospinning to process a local surface of the gate electrode 13 , thereby forming a gate processing layer 15 .

[0073] S2, bonding the detection container 12 and the first substrate 11, so that the detection container 12 partially covers the gate electrode 13 and the first connection electrode 14, and completely covers the gate processing layer 15, and the first connection lead-out terminal 141 is exposed outside the detection container 12, to obtain a detection cavity;

[0074] S3. Deposit and process the independent source electrode 23, drain electrode 24 and second connecting electrode 25 on the second substrate 21 through a mask, and deposit and process the transistor active layer 26 between the source electrode 23 and the drain electrode 24; in a specific embodiment, adhere the cut tape mask to the substrate 21, the tape mask can expose part of the source electrode 23, drain electrode 24 and channel (the tape is cut with a 2mm×4mm window). Then spin-coat or scrape PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid) suspension, dry the sample at 80°C for 5 minutes, remove the tape mask, and then perform annealing at 140°C for 1 hour to form the transistor active layer 26; process the second connecting lead 251 on the second connecting electrode 25;

[0075] S4, bonding the conductive container 22 and the second substrate 21, and making the conductive container 22 partially cover the source electrode 23, the drain electrode 24 and the second connection electrode 25, and completely cover the transistor active layer 26, and the second connection lead-out terminal 251 is exposed outside the conductive container 22; pouring electrolyte II27 into the conductive container 22, and sealing it to obtain a conductive cavity;

[0076] S5. An electrical connection switch 3 is provided between the first connection lead-out terminal 141 and the second connection lead-out terminal 251 to obtain the electrochemical triode biosensor.

[0077] Example 2

[0078] The above-mentioned electrochemical triode biosensor is used to detect uric acid.

[0079] Specifically, the electrolyte I16 used is PBS. The gate electrode 13 is a 100nm thick Pt film prepared by magnetron sputtering of a stainless steel mask, and a graphene oxide film (100nm) is prepared on the surface of the Pt electrode by scraping. After thermal annealing, the gate electrode coated with the graphene oxide film is immersed in a PBS solution of uricase (UOx) (4 hours, 4°C) to allow the uricase to adsorb on the surface of the graphene oxide film; optionally, the first connecting electrode 14 can be prepared at the same time as the gate electrode 13, but no graphene oxide treatment is required; the preparation of the conductive cavity 2 still adopts the process in the above embodiment, and the electrolyte II27 used is a 1M KCl aqueous solution, and is in accordance with Figure 3The connection method shown connects the detection cavity 1 and the conduction cavity 2.

[0080] Two voltage signals are provided by two Keithley 2400 source meters, forming a bias voltage between the source electrode 23 and the drain electrode 24 and the gate electrode 13. One of the source meters is used to measure the current flowing through the transistor active layer 26, and the change of the current over time is monitored by a PC through Matlab software. A certain amount of uric acid PBS solution is dripped into the detection cavity 1 in an orderly manner. When a significant current change is found, the concentration of uric acid in the detection cavity 1 is calculated to obtain the uric acid detection accuracy of the device. The measurement accuracy we obtained is higher than 10 -6 M, the corresponding current change is 5μA (the noise fluctuation of the measurement system is about 1μA). Through the electrical connection switch 3, the connection can be turned on and off. After the detection is completed, the detection cavity 1 can be discarded, and the conduction cavity 2 can be reused.

[0081] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, this specification does not describe all possible combinations of the technical features in the above-described embodiments. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. Moreover, the above-described embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. An electrochemical triode biosensor, characterized in that: Including a detection cavity and a conduction cavity; The detection cavity and the conduction cavity are independent and separated from each other, and the detection cavity and the conduction cavity can be electrically connected for detection; The detection cavity includes a gate electrode and a first connecting electrode; The gate electrode and the first connecting electrode are independently arranged and are partially immersed in the electrolyte I; The conductive cavity comprises a source electrode, a drain electrode and a second connecting electrode; The source electrode, the drain electrode and the second connection electrode are independently arranged and partially immersed in the electrolyte II; a triode active layer is arranged between the source electrode and the drain electrode, and the triode active layer is immersed in the electrolyte II.

2. An electrochemical triode biosensor according to claim 1, characterized in that: A first connection lead-out terminal is provided on the exposed portion of the first connection electrode that is not immersed in the electrolyte I.

3. The electrochemical triode biosensor according to claim 1, characterized in that: A gate processing layer is disposed on a portion of the gate electrode that can be immersed in the electrolyte I.

4. The electrochemical triode biosensor according to any one of claims 1 to 3, characterized in that: The gate electrode and the first connecting electrode are both formed on a first substrate; a detection container is buckled on the first substrate; the detection container is buckled on the first substrate and partially covers the gate electrode and the first connecting electrode; the electrolyte I is contained in the detection container.

5. The electrochemical triode biosensor according to claim 1, characterized in that: A second connection lead-out terminal is disposed on the exposed portion of the second connection electrode that is not immersed in the electrolyte II.

6. An electrochemical triode biosensor according to claim 1 or 5, characterized in that: The source electrode, the drain electrode and the second connecting electrode are all formed on the second substrate; a conductive container is buckled on the second substrate; the conductive container is buckled on the second substrate and partially covers the source electrode, the drain electrode and the second connecting electrode, and completely covers the active layer of the transistor; the electrolyte II is contained in the conductive container.

7. The electrochemical triode biosensor according to claim 1, characterized in that: An electrical connection switch for realizing electrical connection on and off is arranged between the conduction cavity and the detection cavity.

8. A method for preparing an electrochemical triode biosensor, characterized in that: The steps include: S1, depositing and processing a gate electrode and a first connecting electrode on a first substrate; processing a local surface of the gate electrode to form a gate processing layer; processing a first connecting lead-out terminal on the first connecting electrode; S2, bonding a detection container and the first substrate, so that the detection container partially covers the gate electrode and the first connecting electrode, and completely covers the gate processing layer, and the first connecting lead-out terminal is exposed outside the detection container, to obtain a detection cavity; S3, depositing and processing a mutually independent source electrode, a drain electrode and a second connecting electrode on the second substrate, depositing and processing a transistor active layer between the source electrode and the drain electrode; processing a second connecting lead-out terminal on the second connecting electrode; S4, bonding the conductive container to the second substrate, and making the conductive container partially cover the source electrode, the drain electrode and the second connecting electrode, and completely cover the active layer of the transistor, with the second connecting lead-out terminal exposed outside the conductive container; pouring electrolyte II into the conductive container, sealing it, and obtaining a conductive cavity; S5. An electrical connection switch is provided between the first connection lead-out terminal and the second connection lead-out terminal to obtain the electrochemical triode biosensor.

Images