阅读说明：本技术 一种功能化导电墨水及其应用 (Functional conductive ink and application thereof ) 是由 邹鹏 于 2020-12-01 设计创作，主要内容包括：本发明公开了一种功能化导电墨水,所述功能化导电墨水由导电墨水功能材料、水、二乙二醇和丙三醇制成；所述导电墨水功能材料为表面功能化的金属纳米颗粒,其结构如Ⅰ所示；其中为金属纳米颗粒；为媒介体结构；为保护剂；R-1为C、N、O、H构成的有机结构,还公开了其在生物传感器中的应用。由于导电墨水功能材料中连接有电子媒介体结构,制成功能化导电墨水用于导电层后,在其表面附着生物酶制成生物传感器电极,所得生物传感器能在更低的工作电压下检测生物物质；此生物电极拥有更高的电子传输效率,在不减小信号强度同时缩小电极面积,达到使生物传感器小型化的目的。(The invention discloses a functionalized conductive ink which is prepared from a conductive ink functional material, water, diethylene glycol and glycerol; the conductive ink functional material is a metal nano particle with a functionalized surface, and the structure of the conductive ink functional material is shown as I; wherein Is a metal nanoparticle; is a medium structure; is a protective agent; r 1 C, N, O, H, and its application in biosensor. Because the functional material of the conductive ink is connected with an electronic mediator structure, after the functional conductive ink is prepared and used for the conductive layer, biological enzyme is attached to the surface of the functional conductive ink to prepare a biosensor electrode, and the obtained biosensor can detect biological substances under lower working voltage; the bioelectrode has higher electron transmission efficiency, reduces the electrode area without reducing the signal intensity, and achieves the purpose of miniaturizing the biosensor.)

1. A functionalized conductive ink, comprising: the functionalized conductive ink is prepared from a conductive ink functional material, water, diethylene glycol and glycerol; the conductive ink functional material is a metal nanoparticle with functionalized surface, and the structure of the conductive ink functional material is shown as I:

whereinIs a metal nanoparticle;is a medium structure;is a protective agent; r₁C, N, O, H.

2. The functionalized conductive ink of claim 1, wherein: the mediator structure is an organic complex of iron; the R is₁Selected from linear/branched/cyclic alkyl, organic structures containing lipid/ether/amide/quaternary ammonium group/polyethylene glycol, or any combination of the alkyl and the organic structures.

3. The functionalized conductive ink of claim 2, wherein: the R is₁Selected from the following structures or any combination between the following structures:

wherein n is 1-10, R₆、R₇Is H or a linear/branched/cyclic hydrocarbon group, R₆And R₇May be different or the same.

4. The functionalized conductive ink of claim 2, wherein: the mediator structure is ferrocene or a derivative thereof, and the structural formula is as follows:

wherein X₁、X₂、X₃、X₄、X₁’、X₂’、X₃’、X₄’、X₅' each is independently selected from one of the following groups, which may be different or the same:

wherein R is₂、R₃、R₄、R₅Is a structure consisting of H, straight chain/branched chain/cyclic alkyl, and lipid/ether-containing groups.

5. The functionalized conductive ink of claim 1, wherein: the metal in the metal nano-particles is one of Ag, Au, Cu, Zn, Ni, Co, Pd, Pt, Zr, Cr, Ru, Os, Ir, Sn, Pb, Al, Mo and W; the protective agent is one of high molecular polymers with the following structures, and the molecular weight is 500-1000000:

wherein R is a structure consisting of H, straight chain/branched chain/cyclic alkyl, and lipid/ether-containing groups.

6. The functionalized conductive ink of claim 5, wherein: the metal in the metal nano particles is Ag, Au, Pd or Pt; the protective agent is one of polyvinylpyrrolidone, polyacrylic acid, polyacrylate and polyethylene glycol, and the molecular weight is 1000-10000.

7. The functionalized conductive ink according to any one of claims 1 to 6, prepared by the following method:

mixing the conductive ink functional material with water, performing ultrasonic treatment, adding diethylene glycol and glycerol to adjust the viscosity to 5-200CPS,

and obtaining the functionalized conductive ink with the conductive ink functional material mass concentration of 5-40%, and storing after filtering.

8. Use of the functionalized conductive ink according to any one of claims 1 to 7 in a biosensor.

9. The use of the functionalized conductive ink according to claim 8, wherein the biosensor electrode is prepared by printing with a general conductive ink, the functionalized conductive ink completely covers one electrode by an ink-jet printing or micro-dropping method, and is dried and then cured by heating or NIR light, and then a solution containing glucose oxidase is dropped on the surface of the electrode, and the working electrode is formed after drying.

10. The use of the functionalized conductive ink according to claim 9, wherein the temperature of the heat curing is 70-100 ℃; the NIR light curing condition is 800-1200nm and 0.1-2mW/m²。

Technical Field

The invention relates to the technical field of conductive ink for manufacturing electrodes of biosensors, in particular to functionalized conductive ink and application thereof.

Background

With the demand for high precision and high integration of electronic devices, inkjet printing technology is gradually emerging in the field of printed electronics. Compared with the process for preparing the conductive circuit by the conventional printed circuit board, the method for preparing the conductive circuit by the ink jet printing technology has the characteristics of high manufacturing speed, environmental friendliness, simple process, low cost and diversified functions. The production of conductive circuits on flexible circuit boards can greatly increase the production rate of products, and it is critical to develop conductive inks meeting the requirements of ink jet printing equipment and final products. The nano metal particles have the outstanding advantages of small size, difficult agglomeration, low melting point and the like, so the nano metal particles are widely used for research and production of conductive ink. In the aspect of ink-jet printed electronics, printers, inks and substrate conductive inks are mainly involved, and the ink can be applied to aspects such as Radio Frequency Identification (RFID), Organic Light Emitting Diodes (OLED), Printed Circuit Boards (PCB), flexible sensors and the like. The great application potential of the ink-jet conductive ink in RFID antennas, PCB circuit boards and other aspects such as display electrode assemblies and the like makes the ink-jet conductive ink representative of the development direction of thin-film printed electronic materials. At present, several factors such as conductivity, oxidation stability, cost, electromagnetic performance and the like are mainly considered in preparation and selection of the conductive ink, research on functionalization of the conductive ink in a specific direction is not sufficient, and particularly, no conductive ink for optimizing functions of a biosensor exists in the market.

Disclosure of Invention

In order to solve the problems, the invention discloses a functionalized conductive ink which is prepared by dissolving surface functionalized metal nanoparticles serving as a conductive ink functional material, has higher electron transmission efficiency after being printed and prepared into a bioelectrode, and can greatly reduce the area of the electrode on the premise of not reducing the signal intensity.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

a functionalized conductive ink is prepared from a conductive ink functional material, water, diethylene glycol and glycerol; the conductive ink functional material is a metal nanoparticle with functionalized surface, and the structure of the conductive ink functional material is shown as I:

whereinIs a metal nanoparticle;is a medium structure;is a protective agent; r₁C, N, O, H.

In the functionalized conductive ink, the mediator structure is an organic complex of iron; the R is₁Selected from linear/branched/cyclic alkyl, organic structures containing lipid/ether/amide/quaternary ammonium group/polyethylene glycol, or any combination of the alkyl and the organic structures.

The aforementioned functionalized conductive ink, R₁Selected from the following structures or any combination between the following structures:

wherein n is 1-10, R₆、R₇Is H or a linear/branched/cyclic hydrocarbon group, R₆And R₇May be different or the same.

In the functionalized conductive ink, the mediator structure is ferrocene or a derivative thereof, and the structural formula is as follows:

wherein X₁、X₂、X₃、X₄、X₁’、X₂’、X₃’、X₄’、X₅' each is independently selected from one of the following groups, which may be different or the same:

wherein R is₂、R₃、R₄、R₅Is a structure consisting of H, straight chain/branched chain/cyclic alkyl, and lipid/ether-containing groups.

In the functionalized conductive ink, the metal in the metal nanoparticles is one of Ag, Au, Cu, Zn, Ni, Co, Pd, Pt, Zr, Cr, Ru, Os, Ir, Sn, Pb, Al, Mo, and W; the protective agent is one of high molecular polymers with the following structures, and the molecular weight is 500-1000000:

wherein R is a structure consisting of H, straight chain/branched chain/cyclic alkyl, and lipid/ether-containing groups.

In the functionalized conductive ink, the metal in the metal nanoparticles is preferably Ag, Au, Pd or Pt; the protective agent is preferably one of polyvinylpyrrolidone, polyacrylic acid, polyacrylate and polyethylene glycol, and the molecular weight is 1000-10000.

The functional material of the conductive ink in the functionalized conductive ink is prepared by the following steps: dissolving the nano metal particles, and adding surface functionalized molecules into the solutionStirring at room temperature for reaction, and centrifuging at high speed to separate a solid phase from a liquid phase after the reaction is finished; washing the obtained solid phase and then drying in vacuum to obtain the solid phase; the more specific preparation method comprises the following steps: adding nano metal particles into a solvent for ultrasonic treatment, adding surface functionalized molecules after full dissolutionNano metal particles andthe mass ratio of the components is 1000: 1 to 1: 10, the reaction is stirred at room temperature for 8 hours, and the solid-liquid phase is separated by centrifugation (1-5min) at 10000rpm after the reaction is finished; washing the obtained solid phase for 3 times, and vacuum drying to obtain the final product.

The functionalized conductive ink can be prepared as follows:

mixing the conductive ink functional material with water, performing ultrasonic treatment, adding diethylene glycol and glycerol to adjust the viscosity to 5-200CPS, obtaining the functionalized conductive ink with the conductive ink functional material mass concentration of 5-40%, and storing after filtering.

Use of a functionalized conductive ink as described in any of the preceding claims in a biosensor.

The application of the functionalized conductive ink specifically comprises the following steps: firstly, printing general conductive ink to prepare a biosensor electrode, completely covering one electrode by the functional conductive ink through an ink-jet printing or micro-dropping method, drying, then heating for curing or NIR light curing, then dropping a solution containing glucose oxidase on the surface of the electrode, and drying to form a working electrode.

The application of the functionalized conductive ink is that the temperature of the heating and curing is 70-100 ℃; the NIR light curing condition is 800-1200nm and 0.1-2mW/m²。

Taking a biosensor for monitoring glucose as an example, the biosensor consists of three electrodes, wherein a working electrode is provided with biological enzyme, a reference electrode is provided with Ag/AgCl, and the other vacant electrode forms a counter electrode. The electrode preparation method is shown in figure 3: firstly, printing with unfunctionalized conductive ink to obtain a three-electrode structure, and placing an Ag/AgCl reference electrode material on a left electrode; then preparing a working electrode by using the functionalized conductive ink, solidifying, dripping aqueous solution of glucose oxidase on the surface of the working electrode, drying, and then placing the sensor in a glutaraldehyde steam environment to crosslink the glucose oxidase to complete the preparation of the working electrode; and the rest of the vacant electrode is used as a counter electrode, a Hydrophilic Polyurethane (HPU) film is coated on the surface of the biosensor by a slit coating method, and the thickness of the dried film is 2 mu m.

Compared with the prior art, the invention has the beneficial effects that:

the invention discloses a functionalized conductive ink and application thereof, the functionalized conductive ink is prepared by dissolving metal nanoparticles with functionalized surfaces as a conductive ink functional material, the surfaces of the metal nanoparticles are connected with molecules containing an electronic mediator through covalent bonds, the surfaces of the metal nanoparticles are functionalized, the conductive ink prepared by the functionalized conductive ink is printed to form a conductive layer, biological enzyme is attached to the surface of the conductive layer to prepare a biosensor electrode, and by means of an electronic mediator layer directly fixed on the surface of the electrode, electrons generated by enzyme reaction on a working electrode of the biosensor can be directly transmitted to the surface of the electrode, so that the electrode can detect biological substances under lower working voltage, and the sensitivity of the sensor to interfering substances is reduced; meanwhile, the bioelectrode made of the conductive ink has higher electron transmission efficiency, and the area of the bioelectrode is greatly reduced on the premise of not reducing the signal intensity, so that the purpose of miniaturization of the biosensor is achieved.

Drawings

FIG. 1 is a comparison graph of cyclic voltammetry curves of a glucose biosensor prepared from a functionalized conductive ink of the present invention made with a conductive ink functional material and a conductive ink made without surface functionalized silver nanoparticles in a glucose solution;

FIG. 2 is a graph comparing the operating current of glucose biosensors in glucose solution, using the functionalized conductive ink of the present invention made of the functional material of conductive ink, and the conductive ink made of the silver nanoparticles that are not surface-functionalized;

fig. 3 is a schematic view of an electrode preparation method of the biosensor.

Detailed Description

Embodiment 1 of the present invention: a functionalized conductive ink:

silver nanoparticles surface-functionalized with conductive ink functional materialsWater, diethylene glycol and glycerol;is polyvinylpyrrolidone with molecular weight of M_n＝3000g/mol。

The specific preparation method of the conductive ink functional material comprises the following steps: adding silver nano particles into a solvent for ultrasonic treatment, adding surface functionalized molecules after full dissolutionSilver nanoparticles andthe mass ratio of the components is 1000: 1, stirring and reacting for 8h at room temperature, and centrifuging for 5min at 10000rpm after the reaction is finished to separate a solid phase and a liquid phase; washing the obtained solid phase for 3 times, and vacuum drying to obtain the final product.

Example 2: a functionalized conductive ink:

gold nanoparticles surface functionalized with conductive ink functional materialsWater, diethylene glycol and glycerol;is polyacrylic acid, has a molecular weight of M_n＝1000g/mol。

Example 3: a functionalized conductive ink:

from conductive inksFunctional materials, i.e. surface-functionalized palladium nanoparticlesWater, diethylene glycol and glycerol;is polyethylene glycol, and has a molecular weight of M_n＝60000g/mol。

The specific preparation method of the conductive ink functional material comprises the following steps: adding palladium nano particles into a solvent for ultrasonic treatment, adding surface functionalized molecules after full dissolutionPalladium nanoparticles andthe mass ratio of the components is 1: 10, stirring and reacting for 8h at room temperature, and centrifuging at 10000rpm for 1min to separate a solid phase and a liquid phase after the reaction is finished; washing the obtained solid phase for 3 times, and vacuum drying to obtain the final product.

Example 4: a functionalized conductive ink:

gold nanoparticles surface functionalized with conductive ink functional materialsWater, diethylene glycol and glycerol;is polymethyl acrylate, and has a molecular weight of M_n＝800000g/mol。

Example 5: a functionalized conductive ink:

platinum nanoparticles surface-functionalized with conductive ink functional materialsWater, diethylene glycol and glycerol;is a polyurethane acrylic copolymer, and has a molecular weight of M_n＝150000g/mol。

Example 6: example 1 preparation of functionalized conductive ink:

silver conductive ink functional materialAdding water according to the proportion of 0.1g/mL, mixing, carrying out ultrasonic treatment under the condition of ice-water bath, adding diethylene glycol and glycerol to adjust the viscosity to 12CPS, filtering and storing.

Example 7: example 2 preparation of functionalized conductive ink:

the gold is used for conductive ink functional materialAdding water according to the proportion of 0.25g/mL, mixing, performing ultrasonic treatment, adding diethylene glycol and glycerol to adjust the viscosity to 20CPS, filtering and storing.

Example 8: example 3 preparation of functionalized conductive ink:

the functional material of the palladium conductive inkAdding water according to the proportion of 0.40g/mL, mixing, performing ultrasonic treatment, adding diethylene glycol and glycerol to adjust the viscosity to 200CPS, filtering and storing.

Example 9: as shown in fig. 3, the application of the functionalized conductive ink in the biosensor in example 1:

the method comprises the steps of firstly printing and preparing three electrodes of the biosensor by using universal conductive ink, placing an Ag/AgCl reference electrode material on the left electrode, completely covering the middle electrode by using the functional conductive ink in the embodiment 1 through an ink-jet printing method, drying, placing in a drying oven at the temperature of 100 ℃ for 1 hour for heating and curing, dripping a glucose oxidase solution with the mass percentage concentration of 5% on the surface of the electrode, drying, placing the sensor in a steam environment of glutaraldehyde for crosslinking the glucose oxidase, and preparing the working electrode. The other vacant electrode forms a pair of electrodes.

Example 10: example 2 application of functionalized conductive inks in biosensors:

printing and covering a biosensor circuit structure on a PET substrate by using general conductive ink to prepare a biosensor circuit; and then injecting the functionalized conductive ink into an ink box of a DMP-2831 printer, preparing an electrode on a biosensor circuit, drying, placing in a drying oven at the temperature of 80 ℃ for 2 hours for heating and curing, dripping a glucose oxidase solution with the mass percentage concentration of 5% on the surface of the electrode, and drying to form the working electrode.

Example 11: example 3 application of functionalized conductive inks in biosensors:

printing general conductive ink to prepare a biosensor electrode, completely covering one electrode with functional conductive ink by a micro-dropping method, drying, placing in a drying oven at 70 ℃ for 4 hours for heating and curing, dripping a solution containing glucose oxidase on the surface of the electrode, and drying to form a working electrode.

Example 12: example 4 application of the functionalized conductive ink in biosensors, as shown in fig. 3:

printing and preparing three electrodes of the biosensor by using general conductive ink, placing Ag/AgCl reference electrode material on the left electrode, completely covering the middle electrode with the functional conductive ink by a micro-drop method, drying, and performing NIR photocuring (800-1200nm, 1 mW/m)²30s), then dripping a solution containing glucose oxidase on the surface of the electrode, and drying to form a working electrode.

Example 13: example 5 application of functionalized conductive inks in biosensors:

firstly, the general conductive ink is used for printing and preparing the biosensor electrode, then the functional conductive ink is used for completely covering one electrode through ink-jet printing, and NIR photocuring (800-1200nm, 0.1 mW/m) is carried out after drying²60s), then dripping a glucose oxidase solution with the mass percentage concentration of 5% on the surface of the electrode, and drying to form the working electrode.

In order to verify the effect of the present invention, the inventors also performed a product performance comparison test to prepare conductive inks for comparison, and compared the performance of the biosensors respectively prepared from the functionalized conductive inks of the above example 1:

experimental example:

biosensor performance comparison experiment

Firstly, experimental materials:

example 1 functionalized conductive ink, printing the resulting biosensor;

comparison system: preparing conductive ink from the silver conductive ink material which is not subjected to surface functionalization, and then printing the prepared glucose biosensor;

the thickness and the surface roughness of the conductive layer of the two biosensors are approximately the same; the dosage of the enzyme on the working electrode and the shape and the size of the enzyme layer are kept consistent; the HPU film thickness was the same.

Second, comparison experiment of working voltage of biosensor

The cyclic voltammograms of both biosensors were measured in a 100mg/dL glucose solution, and the results are shown in FIG. 1.

As can be seen from the graph, the glucose biosensor (comparative system) made of non-functionalized silver conductive ink reached the maximum current value at the working voltage of 680 mV; the sensor made of the functionalized silver conductive ink can reach the maximum current value at 320mV, which is much lower than the working voltage of a comparison system. The lower working voltage means less interfering substances participating in the reaction, so that the glucose sensor prepared by using the functionalized silver conductive ink has better anti-interference capability.

As can be seen from fig. 1, in the glucose solution with the same concentration, the maximum current measured by the glucose sensor made of the functionalized silver conductive ink reaches 550nA, which is more than four times of that of the contrast system 120nA, which shows that the charge transfer efficiency of the enzyme electrode can be significantly improved, i.e. the sensitivity of the sensor is improved, while the working voltage is reduced.

In addition, the biosensor monitors the biological substance by measuring the magnitude of the generated current, and the following results can be obtained from the data of fig. 1: with approximately the same electrode area and approximately the same electrode surface roughness (i.e., approximately the same total surface area), the use of functionalized conductive ink can produce 550nA ÷ 120nA ≈ 4.6 times the amount of electricity, i.e.: if the electrode is made of the functionalized conductive ink, the current intensity of the electrode made of the non-functionalized conductive ink can be obtained only by 4.6 times of the area of the electrode.

Third, comparison experiment of working current of biosensor

The two biosensors were placed in a glucose solution at 50, 100 and 200mg/dL in this order, and the current signals of the two biosensors were measured. In the experiment, the working voltage of the biosensor made of the functionalized silver conductive ink was set to 320mV, and the working voltage of the contrast system was set to 680mV, and the result is shown in FIG. 2.

As can be seen from the figure, both biosensors were able to respond to the change of glucose concentration in the solution, but the biosensor made of the functionalized silver conductive ink measured a much higher current value in each concentration than the control system, indicating that it could improve the sensitivity of the sensor.

Fourth, conclusion

The experiment shows that the bioelectrode prepared by the functionalized conductive ink has higher electron transmission efficiency, and can reduce the area of the bioelectrode without reducing the signal intensity so as to achieve the aim of miniaturizing the biosensor; meanwhile, the obtained biosensor can detect biological substances at lower working voltage.