CN215525629U

CN215525629U - Screen printing electrode system based on human chorionic gonadotrophin peptide aptamer

Info

Publication number: CN215525629U
Application number: CN202120432274.3U
Authority: CN
Inventors: 余鹏; 赵佳
Original assignee: Changsha Xinli Zhihe Technology Co ltd
Current assignee: Changsha Xinli Zhihe Technology Co ltd
Priority date: 2021-02-26
Filing date: 2021-02-26
Publication date: 2022-01-14
Anticipated expiration: 2031-02-26

Abstract

The utility model relates to the technical field of biological recognition sensors for in vitro detection, in particular to a silk-screen printing electrode system based on a human chorionic gonadotropin peptide aptamer, which comprises a substrate, electrode strips, a working electrode and an insulating layer, wherein the electrode strips are arranged on the substrate; the working electrode is an electrode modified by a human chorionic gonadotropin peptide aptamer; the number of the working electrodes is at least one; the electrode strips are conductive circuits formed by conductive materials; the number of the electrode strips is at least one; each electrode strip is connected with a working electrode; the insulating layer covers the substrate and the electrode strips. The electrode system of the utility model can accurately detect the HCG content in biological samples such as blood and urine, and has low cost and simple operation. The kit is used for HCG detection, and the result shows that the specificity of HCG and peptide aptamer combination is good, the sensitivity is high, the stability is good, the kit can be produced in batch, and the miniaturization is expected to be realized, so that the kit is used for household rapid detection.

Description

Screen printing electrode system based on human chorionic gonadotrophin peptide aptamer

Technical Field

The utility model relates to the technical field of biological recognition sensors for in-vitro detection, in particular to a screen printing electrode system based on a human chorionic gonadotropin peptide aptamer.

Background

Biosensors are a special class of sensors, mainly used for the determination of trace amounts of chemical and biological substances. Structurally, the biosensor mainly comprises two parts, namely a biosensing element (such as enzyme, protein, DNA, aptamer Apatemer, antibody, antigen, biomembrane, microorganism, cell, tissue and the like) and a signal converter (converting biochemical reaction into quantifiable physical or chemical signals). The specific principle is that the substance to be detected diffuses into the immobilized biological sensitive film layer, after molecular recognition, biochemical reaction occurs, the generated reaction signal is converted into a signal which can be quantified and processed by the transducer, and then amplified and output by the secondary instrument (detection amplifier).

Besides maintaining the functionality of biomolecules, the electrode of the biosensor needs to ensure the stability after being fixed on the surface of an electrode material, and can be stored for a long time after being fixed or still has activity after being modified with chemical groups (such as-COOH, -NH2, -OH, -SH, etc.). The sensitivity, response time, stability and reproducibility of biosensors are largely dependent on the stability of the electrodes. The stability of the electrode is related to the manufacturing process thereof and the type, amount, etc. of the immobilized biomolecules.

Screen printing is an old printing technique. The screen printing is composed of five major elements, namely a screen printing plate, a scraper, ink, a printing table and a printing stock. The basic principle that the meshes of the image-text part and the non-image-text part of the screen printing plate are permeable to ink and impermeable to ink is utilized to print. When printing, ink is poured into one end of the screen printing plate, a scraper plate is used for applying a certain pressure to the ink position on the screen printing plate, meanwhile, the scraper plate moves towards the other end of the screen printing plate at a constant speed, and the ink is extruded onto a printing stock from meshes of the image-text part by the scraper plate in the moving process.

The screen-printed electrode is manufactured based on the screen printing technology, is one of biosensors since the nineties of the 20 th century, and is now used in electrochemical analysis in the fields of environment, medicine or agricultural food. The method has many advantages, so that the method becomes an ideal tool for quality control, scientific research and electrochemical teaching, but has the problems of poor specificity and stability, low detection accuracy, difficulty in controlling electrode errors, high possibility of falling off of electrodes and the like.

SUMMERY OF THE UTILITY MODEL

Based on this, it was an object of the present invention to provide a screen-printed electrode system based on human chorionic gonadotropin peptide aptamers.

The technical scheme of the utility model is as follows:

a screen printed electrode system based on a human chorionic gonadotropin peptide aptamer comprising: the electrode structure comprises a substrate, electrode strips, working electrodes and an insulating layer;

the working electrode is an electrode modified by a human chorionic gonadotropin peptide aptamer; the number of the working electrodes is at least one; the electrode strips are conductive circuits formed by conductive materials; the number of the electrode strips is at least one;

the electrode strips are connected with the working electrodes, and each electrode strip is connected with one working electrode; the electrode strip and the working electrode are positioned between the base and the insulating layer; the insulating layer covers the substrate and the electrode strips.

Further, the screen-printed electrode based on the human chorionic gonadotropin peptide aptamer further comprises a counter electrode, and the counter electrode is connected with a single electrode strip.

Further, the screen-printed electrode based on the human chorionic gonadotropin peptide aptamer further comprises a reference electrode, and the reference electrode is connected with a single electrode strip.

Further, the substrate includes flexible substrates such as a polyvinyl chloride (PVC) substrate, a polyethylene terephthalate (PET) substrate, and a Polycarbonate (PC) substrate; or a rigid substrate such as a ceramic plate, a glass plate, an aluminum sheet, or the like.

Further, the working electrode comprises a carbon electrode layer, a metal nanoparticle layer and a peptide aptamer layer; the metal nano particle layer covers the carbon electrode layer; the peptide aptamer layer is coated on the metal nanoparticle layer, and the peptide aptamer in the peptide aptamer layer is combined with the metal nanoparticle in the metal nanoparticle layer through self-assembly.

Further, the working electrode further comprises a blocking layer for blocking blank active sites not bound to the human chorionic gonadotropin peptide aptamer.

Further, the human chorionic gonadotropin peptide aptamer comprises a peptide chain structure shown in any one of P1 to P6:

P1：MHLMRMKPLLLT；

P2：MHPRKMLQLMLN；

P3：STRLRRRSRRQT；

P4：PPLRINRHILTR；

P5：MKLKPMRIMINP；

P6：MKSRMLPLNRRL。

further, the human chorionic gonadotropin peptide aptamer comprises a modified peptide chain structure; the modifications include polar glycine modifications; the polar glycine modifications include: introducing 3 polar glycines at least one end of the peptide chain structure shown in any one of P1-P6.

Preferably, the peptide chain structure modified by polar glycine is the peptide chain structure shown as P11-P61:

P11：GGGMHLMRMKPLLLT；

P21：GGGMHPRKMLQLMLN；

P31：GGGSTRLRRRSRRQT；

P41：GGGPPLRINRHILTR；

P51：GGGMKLKPMRIMINP；

P61：GGGMKSRMLPLNRRL。

further, the peptide chain structure shown by P1 to P6 or the peptide chain structure shown by P11 to P61 may also be a peptide chain structure modified by cysteine, wherein the cysteine modification comprises: cysteine was introduced at one end of each of the peptide chain structures represented by P1 to P6 or each of the peptide chain structures represented by P11 to P61.

Further, the insulating layer is an insulating ink layer.

The utility model has the beneficial effects that:

compared with the prior art, the utility model provides a screen printing electrode system for detecting human chorionic gonadotropin based on peptide aptamer. Metal nano particles are electrodeposited on a working electrode; modifying the peptide aptamer to the surface of the working electrode through self-assembly; forming a sealing layer by adopting hexamercaptohexanol, and sealing blank active sites of the electrode; the electrode is used for HCG detection, and the result shows that the specificity of HCG and peptide aptamer combination is good, the sensitivity is high, the stability is good, the electrode can be produced in batch, and the miniaturization is expected to be realized, so that the electrode is used for household rapid detection.

The electrode system of the utility model can accurately detect the HCG content in biological samples such as blood and urine, and has low cost and simple operation.

For a better understanding and practice, the utility model is described in detail below with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of the electrode architecture of the present invention.

FIG. 2 is a screen layout drawing, in which FIG. 2A is a drawing of a wire and electrode screen, FIG. 2B is a drawing of an insulating ink screen, and FIG. 2C is a drawing of two screen printing products.

Fig. 3 is a schematic assembly of the wire electrode architecture of the present invention.

Description of reference numerals:

100. a substrate; 200. an electrode strip; 300. a counter electrode; 400. a working electrode; 500. a reference electrode; 600. an insulating layer; 610. the electrode is exposed.

Detailed Description

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like, referred to or may be referred to in this specification, are defined relative to their configuration, and are relative concepts. Therefore, it may be changed according to different positions and different use states. Therefore, these and other directional terms should not be construed as limiting terms.

The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

The specific techniques or conditions not indicated in the examples of this application are performed according to the techniques or conditions described in the literature in the field or according to the product description. The reagents or instruments used in the examples of the present application are not indicated by manufacturers, and are all conventional products available from commercial sources and the like.

Referring to fig. 1 and 3, the screen-printed electrode system based on human chorionic gonadotropin peptide aptamers of the present invention comprises: a substrate 100, an electrode strip 200, a working electrode 400, and an insulating layer 600;

the working electrode 400 is a human chorionic gonadotropin peptide aptamer modified electrode; the number of the working electrodes 400 is at least one; the electrode strips 200 are conductive lines formed by conductive materials; the number of the electrode strips 200 is at least one;

the electrode strips 200 are connected with the working electrodes 400, and each electrode strip 200 is connected with one working electrode 400; the electrode strip 200 and the working electrode 400 are located between the substrate 100 and the insulating layer 600; the insulating layer 600 covers the substrate 100 and the electrode bars 200; the insulating layer 600 has an electrode exposing portion 610 for exposing an electrode.

In a single channel electrode, the number of the working electrodes 400 is one; in the multi-channel electrode, the working electrode 400 may be plural. The electrode strips 200 are current paths for current to travel through which conductive paste is screen printed onto the substrate 100, each of which connects to an electrode (here, electrodes include, but are not limited to, working electrode 400).

In some embodiments, the screen-printed electrode system based on human chorionic gonadotropin peptide aptamers further comprises a counter electrode 300, wherein the counter electrode 300 is connected with a single strip of the electrodes 200.

In some embodiments, the screen printed electrode system based on human chorionic gonadotropin peptide aptamers further comprises a reference electrode 500, said reference electrode 500 being connected to a separate one of said electrode strips 200.

In some embodiments, the substrate 100 includes a flexible substrate such as a polyvinyl chloride (PVC) substrate, a polyethylene terephthalate (PET) substrate, a Polycarbonate (PC) substrate, or the like; or a rigid substrate such as a ceramic plate, a glass plate, an aluminum sheet, or the like.

In some embodiments, the working electrode 400 comprises a carbon electrode layer, a metal nanoparticle layer, a peptide aptamer layer; the metal nano particle layer covers the carbon electrode layer; the peptide aptamer layer is coated on the metal nanoparticle layer, and the peptide aptamer in the peptide aptamer layer is combined with the metal nanoparticle in the metal nanoparticle layer through self-assembly.

Specifically, one of the forming methods of the metal nanoparticle layer is as follows: the gold nanoparticle layer is formed by depositing chloroauric acid on the surface of the working electrode 400.

In some embodiments, the working electrode 400 further comprises a blocking layer for blocking the vacant active sites formed by self-assembly.

In some embodiments, the peptide aptamer is a human chorionic gonadotrophin peptide aptamer.

In some embodiments, the human chorionic gonadotrophin peptide aptamer comprises a peptide chain structure as set forth in any one of P1 to P6:

P1：MHLMRMKPLLLT；

P2：MHPRKMLQLMLN；

P3：STRLRRRSRRQT；

P4：PPLRINRHILTR；

P5：MKLKPMRIMINP；

P6：MKSRMLPLNRRL。

in some embodiments, the human chorionic gonadotrophin peptide aptamer comprises a peptide chain structure that is a modified peptide chain structure; the modifications include polar glycine modifications; the polar glycine modifications include: introducing 3 polar glycines at least one end of the peptide chain structure shown in any one of P1-P6.

In some embodiments, the polar glycine modified peptide chain structure is the peptide chain structure shown as P11-P61:

P11：GGGMHLMRMKPLLLT；

P21：GGGMHPRKMLQLMLN；

P31：GGGSTRLRRRSRRQT；

P41：GGGPPLRINRHILTR；

P51：GGGMKLKPMRIMINP；

P61：GGGMKSRMLPLNRRL。

in some embodiments, the peptide chain structure of P1-P6 or the peptide chain structure of P11-P61 may also be a peptide chain structure modified with cysteine including: cysteine was introduced at one end of each of the peptide chain structures represented by P1 to P6 or each of the peptide chain structures represented by P11 to P61.

In some embodiments, the insulating layer is an insulating ink layer.

Example one preparation of a Screen-printed electrode System based on a human chorionic gonadotropin peptide aptamer according to the utility model

This example illustrates the preparation of the screen-printed electrode system for the detection of human chorionic gonadotropin based on peptide aptamers according to the utility model with a three-electrode system only. The screen-printed electrode system for detecting human chorionic gonadotropin based on the peptide aptamer can also be a single-electrode system or a double-electrode system.

Preparation of primary and secondary electrode system

1.1 selection of materials

1.1.1 substrates

The substrate 100 is selected mainly considering heat resistance and flatness, and the heat curing temperature of the slurry reaches 120 ℃, so that a high-temperature resistant base material is selected; electrodes generally require a substrate surface to provide better planarity due to the need for surface molecular assembly. The present embodiment preferably uses a PET material as the substrate.

PET (polyethylene terephthalate) material, commonly known as polyester resin, is the most important variety of thermoplastic polyester. The high-toughness high; the electric insulation performance is good, and the influence of temperature is small; the folding resistance is good, and the oil resistance, the fat resistance, the olefine acid resistance, the dilute alkali resistance and the resistance to most solvents are achieved; the high-temperature and low-temperature resistant rubber has excellent high-temperature and low-temperature resistant performance, can be used for a long time within the temperature range of 120 ℃, can resist high temperature of 150 ℃ and low temperature of-70 ℃ in a short time, and has little influence on the mechanical performance of the rubber at high and low temperatures; low gas and water vapor permeability, excellent gas, water, oil and odor barrier performance, no toxicity, no odor and high sanitary safety. The atomic force microscope inspects the surface appearance and the flatness of the PET base material (0.03cm), and the result shows that the PET base material can provide good surface flatness for the screen printing electrode.

1.1.2 slurries

This example preferably employs a three-electrode system and compares the stability of the silver/silver chloride (80/20) paste and the stability of the carbon paste printed reference electrode 500, with silver/silver chloride (80/20) being selected as the reference electrode. The carbon paste prints the counter electrode 300, the working electrode 400 and the conductive lines, and the green heat-curable insulating ink prints the insulating layer. Silver/silver chloride (80/20), the ratio of silver to silver chloride being 80: 20, low half-cell potential, strong adhesive force, fast curing, good current sensing, and resistance value less than 0.465 omega/cm²And curing conditions are as follows: curing at 120 ℃ for 30 min. Carbon paste, low resistance (identification resistance of 10 omega/cm)²) Strong adhesive force, fast curing, good flexibility, excellent silk-screen printing performance and curing conditions: curing at 120 ℃ for 30 min. The insulating ink has high resistance value, strong adhesive force, green surface, excellent bending property, fast curing and excellent silk-screen printing performance, and the curing conditions are as follows: curing at 120 ℃ for 30 min.

1.2 Screen printing plate design

A 34mm by 12mm screen printed electrode as shown in figure 1 was designed according to the requirements of the three electrode system screen printed electrode. As shown in fig. 2 (where fig. 2A is a diagram of a wire and electrode screen, fig. 2B is a diagram of an insulating ink screen, and fig. 2C is a diagram of two screen-printed finished products), the screen content is 40cm by 50cm, and 84 electrodes can be printed on each screen. Screen printing plate parameters: tension 20N, mesh 300, film thickness 20 μm. The larger the mesh is, the less the ink is on the surface of the substrate, the larger the resistance is, but the flatness is improved; the smaller the mesh, the more ink is permeated, and the plate pasting is easier.

1.3 Screen printing step

Firstly, cutting a printed substrate 100, namely a PET polyester film into 50 x 60cm, washing with ultrapure water, drying, baking in an oven at 120 ℃ for 15min to prevent the plate from deforming in the subsequent high-temperature heating process, and cooling for later use.

And secondly, cleaning the screen printing plate and the scraper by using screen washing water, and naturally volatilizing for later use.

And thirdly, when the electrode is printed, adjusting the inclination angle of the scraper and the screen printing plate to be 60-80 degrees, adjusting the screen distance to be h 2-3 mm, and fixing the screen printing plate.

The angle of the scraper is the included angle formed by the scraper and the screen printing plate. The blade angle is large, the extrusion force of the scraper to the ink is small, so the ink discharging amount is small, but the pressure is large, the friction force with the screen is large, the extrusion force of the scraper to the ink is large, the oil discharging amount is also large, but the oil filling amount is excessive, and the contact with the printing surface is deteriorated.

The screen pitch refers to the distance between the screen and the substrate, and is denoted by h. The mesh pitch is such that the screen can be printed in line contact or line separation. h >0 is called off-screen printing and is properly adjusted according to the effect. The larger the mesh distance is, the stronger the resilience force of the silk screen is, and the higher the mesh stripping speed is, so that the pattern is clearer. However, as the screen pitch increases, the screen tension distortion increases, which leads to errors in the size of the printed pattern and errors in the positional accuracy.

Fourthly, preparing conductive carbon paste according to the product specification (manufacturer: Yimei group), stirring for 5min by a precision speed regulation mixer, and placing on a screen. After printing conductive silver paste on the sheet according to the graph, drying for 60min at 140 ℃, recovering the paste, cleaning a screen printing plate, a scraping glue and a scraper, and printing other pastes according to the same method, wherein the drying conditions are shown in table 1.

Table 1: drying conditions of each slurry layer

Slurry material	Treatment temperature (. degree.C.)	Treatment time (min)
			Carbon slurry	120	30
Silver/silver chloride	120	30
			Insulating ink	120	30

TABLE 6

And fifthly, randomly extracting screen printing electrodes of different batches to test the resistance, and comparing the difference in batches. The electrochemical behavior of the screen-printed electrode in the potassium ferricyanide solution is researched by cyclic voltammetry, the scanning speed is 100mV/s, and the result shows that the intra-batch differential RSD is less than 5%.

1.4 deposition of chloroauric acid on the surface of the working electrode

Preparation of 1mM chloroauric acid (HAuCl)₄) And putting the electrode into the chamber for electrodeposition. Deposition conditions are as follows: setting the voltage of Cyclic Voltammetry (CV) to be 0 to-1.4V, 15 circles and sweeping speed0.5V/s. Electrodeposition image as shown in fig. 3, the electrochemical properties of the electrode were observed in the electrolyte solution after electrodeposition was completed: the impedance was observed by performing cyclic voltammetric scanning and alternating current impedance scanning (CV condition: -0.3-0.6V, 0.05V/s, alternating current impedance (EIS) scanning condition: 1-10000 Hz), and the resistance before and after electrodeposition was decreased from 700. omega. to 50. omega. and the current response was increased from 150. mu.A to 220. mu.A.

Secondly, preparing a screen printing electrode system based on a human chorionic gonadotropin peptide aptamer

2.1 peptide aptamer modified working electrode

Weighing 72mg of TCEP (mw: 286.65g/mol, 99.4%), adding 5mLPBS, and preparing 50mM TCEP reducing agent solution; adding 1mL LPBS into 2mg of peptide fragments, and uniformly mixing by vortex to prepare 2mg/mL of peptide aptamer solution; taking 100 mu L of the prepared 2mg/mL peptide aptamer solution, adding 100 mu L of the prepared TCEP solution to prepare 1mg/mL (5mM) peptide aptamer standard solution (the concentration of TCEP is 25mM, and the reduction ratio is 1: 5); and (3) sucking 20 mu L of peptide standard solution (50 mu M) and dropwise adding the peptide standard solution to the surface of the working electrode, incubating at room temperature for self-assembly for 22h, washing the modified surface of the electrode by PBS (phosphate buffer solution), removing unbound free polypeptide on the surface of the electrode, and gently blowing residual liquid on the surface of the electrode by an aurilave.

After the modification is completed, in the electrolyte Fe (CN)6^3-/4-Recording the electrochemical properties of the modified electrode in solution, DPV (differential pulse voltammetry) parameters: pluse Height: 25mV, Pluse Width: 0.01s, Step Height: 10mV, Step Width: 0.2 s; EIS parameters (frequency range): 10000 Hz-1 Hz.

2.2 Hexamethyhydrylhexanol (MCH) does not bind to the blank active site of the human chorionic gonadotropin peptide aptamer

1.37mg of MCH (AR, mw 134.24, 98%) was weighed and added to 10ml pbs to prepare a 1mM MCH solution; 15 microliter MCH solution (1mM) is absorbed and dripped on the surface of the working electrode 400, the incubation is carried out for 30min at room temperature, and the electrode modified surface is washed by PBS and dried.

After the blocking was completed, 80. mu.L of Fe (CN)6 was dropped on the three electrodes^3-/4-Solution, recording the electrochemical properties of the closed electrode, DPV parameters: pluse Height: 25mV, Pluse Width: the time of the reaction is 0.01s,step Height: 10mV, Step Width: 0.2 s; EIS parameters (frequency range): 10000 Hz-1 Hz.

Example two Performance validation of a Screen-printed electrode System based on Adaptation of human chorionic gonadotropin peptide

(I) specificity verification test

The selectivity of the peptide aptamer electrode of the present invention was examined using Thyroid Stimulating Hormone (TSH), Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH) as interfering substances. The results show that: the response of the electrode system to each concentration of the three interference substances is lower than 3% of the HCG quantitative lower limit concentration response, which shows that the electrode system constructed by the utility model has specificity to the detection of HCG.

(II) stability verification test

Working solutions with the concentrations of 5mIU/mL, 125mIU/mL and 1500mIU/mL are prepared from HCG standard substances, and 6 branches of the peptide aptamer modified electrode system are prepared according to the standard method of the first embodiment. The first measurement: three HCG working solutions with the concentration of 5mIU/mL, 125mIU/mL and 1500mIU/mL were used, and three electrodes were stored at 4 ℃. And (3) second measurement: and (3) taking three other electrodes after being stored at 4 ℃ for 30 days, measuring HCG working solution of 5mIU/mL, 125mIU/mL and 1500mIU/mL, and comparing the resistance change and current response of the electrode modified by the same method in the same batch of the first measurement, wherein the current response of 5mIU/mL is 95 percent of the first measurement, the current response of 125mIU/mL is 92 percent of the first measurement, and the current response of 1500mIU/mL is 90 percent of the first measurement, and the result shows that the stability of the electrode system is excellent.

(III) accuracy and precision

Working solutions with the concentrations of 5mIU/mL, 125mIU/mL and 1500mIU/mL are prepared from HCG standard substances, the same batch of electrode systems prepared according to the method in the embodiment I is used for determination, the response is substituted into a linear equation to obtain the concentration, the concentration is compared with the real concentration, the accuracy of the three concentrations is in the range of 85% -115%, and the detection requirement of a biological sample is met.

Under the same conditions, five modified electrode systems prepared according to the method in the first embodiment are used for detecting HCG working solution (125mIU/mL) with the same concentration, the relative standard error is respectively 4.1% and less than 15%, and the detection requirement of the biological sample is met.

Wherein the linear equation is: Y0.3610X + 64.92); y is the resistance difference before and after HCG incubation by the electrode, and X is the concentration of HCG, and the unit of the concentration is mIU/mL.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. A screen-printed electrode system based on a human chorionic gonadotropin peptide aptamer, wherein the electrode system comprises: the electrode structure comprises a substrate, electrode strips, working electrodes and an insulating layer;

the electrode strips are connected with the working electrodes, and each electrode strip is connected with one working electrode; the insulating layer covers the substrate and the electrode strips.

2. The human chorionic gonadotropin peptide aptamer based screen printed electrode system according to claim 1, wherein said electrode system further comprises a counter electrode connected to a single one of said electrode strips.

3. The human chorionic gonadotropin peptide aptamer based screen printed electrode system according to claim 1, wherein said electrode system further comprises a reference electrode connected to a separate one of said electrode strips.

4. The screen-printed electrode system based on a human chorionic gonadotropin peptide aptamer according to any of claims 1 to 3, wherein the substrate comprises a polyvinyl chloride substrate, a polyethylene terephthalate substrate, a polycarbonate substrate, a ceramic plate, a glass plate or an aluminum plate.

5. The screen-printed electrode system based on human chorionic gonadotropin peptide aptamer according to any of claims 1 to 3, wherein the working electrode comprises a carbon electrode layer, a metal nanoparticle layer, a peptide aptamer layer; the metal nano particle layer covers the carbon electrode layer; the aptamer layer overlies the metal nanoparticle layer.

6. The human chorionic gonadotropin peptide aptamer based screen printed electrode system according to claim 5 wherein the working electrode further comprises a sealing layer.

7. The screen-printed electrode system based on a human chorionic gonadotrophin peptide aptamer according to any one of claims 1 to 3, wherein the human chorionic gonadotrophin peptide aptamer comprises a peptide chain structure as shown in any one of the following P1 to P6:

P1：MHLMRMKPLLLT；

P2：MHPRKMLQLMLN；

P3：STRLRRRSRRQT；

P4：PPLRINRHILTR；

P5：MKLKPMRIMINP；

P6：MKSRMLPLNRRL。

8. the screen-printed electrode system based on a human chorionic gonadotrophin peptide aptamer according to claim 7, wherein said human chorionic gonadotrophin peptide aptamer comprises a peptide chain structure comprising 3 polar glycine structures on at least one end.

9. The screen-printed electrode system based on a human chorionic gonadotrophin peptide aptamer according to claim 8, wherein said human chorionic gonadotrophin peptide aptamer comprises a peptide chain structure comprising a cysteine structure at one end of the peptide chain structure.

10. The screen-printed electrode system based on human chorionic gonadotropin peptide aptamer according to any of claims 1 to 3, wherein the insulating layer is an insulating ink layer.