CN108088881A - A kind of preparation method based on polymer-carbon nanotube enzyme-free glucose sensor - Google Patents

Abstract

The invention discloses a method based on the amphiphilic polymer-modified carbon nanotube hybrid body as a carrier, loaded with metal nano-catalyst particles, and applying it to making a glucose sensor. The method includes the preparation of the polymer-carbon nanotube hybrid and the construction of an enzyme-free glucose sensor. Using the assembly driving force of amphiphilic macromolecules to realize one-step co-assembly of macromolecules and carbon nanotubes, a polymer-carbon nanotube hybrid was prepared. While this hybrid has excellent stability, it combines the advantages of the two materials, with good electrical conductivity and large surface area; therefore, it can be used as an electrode modification material to effectively load metal nanomaterials with catalytic activity. Particles, an enzyme-free glucose sensor with good stability, high sensitivity and wide detection range was prepared. In addition, the enzyme-free glucose sensor is easy to be integrated and applied to microelectronic devices, and is expected to be used in biomedicine, life and health and other fields.

Description

A kind of preparation method based on polymer-carbon nanotube enzyme-free glucose sensor

technical field

The invention relates to the field of electrochemical sensors and the field of macromolecular self-assembly, in particular to a carbon nanotube hybrid modified by an amphiphilic polymer as a carrier, loaded with metal nano-catalyst particles, and applied to the production of enzyme-free Methods for Glucose Sensors.

Background technique

Diabetes is a growing health problem worldwide that can be accompanied by several serious complications. According to the report of the World Health Organization, there are about 35 million people in the world suffering from diabetes. A large amount of evidence shows that the glucose content in the blood of diabetic patients is higher than the normal level. On the other hand, the excretion of glucose in the urine can also reflect severe kidney disease. Therefore, it is particularly important to accurately detect the glucose content in body fluids. At present, the methods for detecting glucose include: chromatography, spectroscopy and electrochemical methods, etc., and the glucose sensor has the advantages of miniaturization, low cost, and rapidity. Therefore, glucose sensors play an important role in the monitoring and control of diabetes. At present, the most widely used glucose sensor is based on enzyme catalysis. However, because the enzyme itself is easily affected by temperature, pH, humidity and chemical substances, the stability and reusability of glucose enzyme sensors are relatively poor. Therefore, it is of great practical significance to develop a fast, simple and reliable enzyme-free glucose sensor.

Carbon nanotubes are a one-dimensional quantum material with a special structure (the radial dimension is on the nanometer scale, the axial dimension is on the micron scale, and both ends of the tube are basically sealed), with a large specific surface area and high chemical stability. Sex, strong adsorption capacity and excellent electrical conductivity. Therefore, when carbon nanotubes are used as a modifier for electrochemical reaction electrodes, they exhibit extraordinary electron migration support capabilities, and have good electrochemical and chemical stability in aqueous and non-aqueous solutions.

Metal nanomaterials have attracted extensive attention due to their high specific surface area and high catalytic activity. Using nanotechnology, it is expected to improve the sensitivity, detection range and response time of sensors. Metal electrode materials commonly used in glucose sensors include noble metals such as Pt, Au, Rd, and Ru, and transition metal oxides such as NiO, MnO ₂ , CoO, ZnO, and CuO. However, the catalytic activity of nanomaterials strongly depends on their size and their distribution on the support, so choosing a suitable support is very important for improving the catalytic performance of the sensor.

In order to make full use of these two nanomaterials, people have further tried to use carbon nanotubes as templates to support metal nanocatalysts, but due to the special structure of carbon nanotubes, their solubility is not good, and they are easy to entangle and agglomerate. Surface modification of CNTs is required to obtain uniformly dispersed nanoparticles through covalent or non-covalent interactions, which can improve the dispersibility of carbon tubes in various organic solvents and compatibility with polymer matrices, thereby enhancing the composite Material properties.

Amphiphilic polymers are formed by the regular or random arrangement of hydrophilic and hydrophobic segments, so they can self-assemble in selective solvents to form various shapes, such as spherical, rod, bowl, vesicle, etc. structure and have surface active properties. In the self-assembly process of amphiphilic polymers, if the π-π interaction, hydrogen bond interaction or hydrophilic-hydrophobic interaction between carbon nanotubes and polymers can be used to break the intermolecular force between carbon nanotubes, it is expected to obtain uniform and stable The carbon nanotube dispersion makes the carbon nanotube more widely used in the field of enzyme-free sensors.

Contents of the invention

In view of the problems existing in the prior art, the object of the present invention is to provide a method based on amphiphilic polymer-modified carbon nanotube hybrids as a carrier, loaded with metal nano-catalyst particles, and applied to the production of glucose sensors . The present invention introduces a monomer structure unit capable of interacting with carbon nanotubes into the main chain of amphiphilic macromolecules, and simultaneously introduces conductive carbon nanotubes in the self-assembly process of amphiphilic macromolecules, and utilizes the assembly drive of amphiphilic macromolecules To realize the one-step co-assembly of macromolecules and carbon nanotubes, and prepare polymer-carbon nanotube hybrids. The prepared polymer-carbon nanotube hybrid can effectively integrate the "softness" of the polymer and the "hardness" of the carbon nanotube, so that it has excellent stability; in addition, this polymer-carbon nanotube hybrid is polymeric The structure of the carbon nanotubes is modified by the material nanoparticles, the carbon nanotubes can improve the electrical conductivity of the hybrid, and the polymer nanoparticles can greatly increase the specific surface area of the hybrid. Therefore, using this conductive polymer-carbon nanotube hybrid as an electrode modification material can effectively load metal nanoparticles with catalytic activity, thereby preparing an enzyme-free enzyme with good stability, high sensitivity, and a wide detection range. Glucose sensor.

Technical scheme of the present invention is as follows:

A kind of preparation method based on polymer-carbon nanotube enzyme-free glucose sensor, the specific steps of the preparation of polymer-carbon nanotube hybrid body, the construction of enzyme-free glucose sensor are as follows:

(1) Preparation of polymer-carbon nanotube hybrids

Dissolve the amphiphilic polymer in an organic solvent, add carbon nanotubes, and ultrasonically disperse for 1h to 24h, so that the amphiphilic polymer and carbon nanotubes can fully interact to obtain a uniformly dispersed amphiphilic polymer/carbon nanotube dispersion; Slowly drop ultrapure water into the dispersion to carry out self-assembly, and stir for 1h to 24h. After assembly, place the mixed solution in a dialysis bag and dialyze for 1d to 7d to obtain a polymer-carbon nanotube hybrid solution.

The amphiphilic polymer is one of block copolymers, graft copolymers, random copolymers, branched polymers, and conjugated polymers, and the organic solvent is N,N-dimethylformamide , tetrahydrofuran, dimethyl sulfoxide, dioxane; the initial solubility of the amphiphilic polymer is 0.1mg/mL～200mg/mL; the mass ratio of the amphiphilic polymer to carbon nanotubes is 1 :0.01～1:1, the force between the amphiphilic polymer and the carbon nanotube is non-covalent bond interaction including one or more of hydrogen bond interaction, electrostatic interaction, π-π interaction, and coordination kind.

(2) Construction of an enzyme-free glucose sensor

The modified electrode is pretreated, and then the polymer-carbon nanotube hybrid solution in step (1) is modified onto the surface of the electrode by drop coating, spin coating or electrophoretic deposition to obtain a polymer-carbon nanotube hybrid modification Electrodes were dried at room temperature. Subsequently, by vacuum sputtering or electrochemical reduction of the metal nano catalyst precursor, evenly distributed metal nano catalyst particles are generated on the surface of the modified electrode, that is, an enzyme-free glucose sensor is obtained.

The electrode is one of a gold electrode, a glassy carbon electrode, an ITO electrode, and a carbon paste electrode; the concentration of the amphiphilic polymer in the polymer-carbon nanotube hybrid solution is 0.1 mg/mL to 200 mg/mL, The mass ratio of the amphiphilic polymer to the carbon nanotube is 1:0.01 to 1:1; the drip coating method is to pipette 5 μL to 30 μL of the polymer-carbon nanotube hybrid solution and drop-coat it on the electrode surface; the electrophoretic deposition The method is to immerse the electrode in the polymer-carbon nanotube hybrid solution, and modify the polymer-carbon nanotube hybrid on the surface of the electrode by controlling the voltage and time. The specific electrophoretic deposition process conditions are: deposition voltage 0.5V ～10V, deposition time 1min～10min; the metal nanocatalyst is one of Pt, Pb, Ni, Cu, Au, Ag, NiO, MnO ₂ , CoO, ZnO, CuO; the concentration of the precursor solution is 0.01 mmol/L～10mmol/L, the electrochemical reduction method is one of cyclic voltammetry, constant potential method and constant current method.

The beneficial technical effects of the present invention are:

1. The present invention uses amphiphilic macromolecules to modify carbon nanotubes to prepare polymer-carbon nanotube hybrids, which are used as carriers to load metal nano-catalyst particles for the construction of enzyme-free glucose sensors. The prepared hybrid is a composite material of organic polymer and inorganic carbon nanotubes, which can combine the unique advantages of the two and has excellent comprehensive performance; the polymer is decorated on the surface of carbon nanotubes in the form of nanoparticles, which can effectively improve the composite material. specific surface area, and the introduction of carbon nanotubes can greatly improve the electrical conductivity of the material; using this hybrid as a carrier to support metal nanocatalyst particles can increase the loading capacity of metal nanocatalyst particles, and can play the role of carbon nanotubes and The synergistic catalytic effect of the metal nano-catalyst particles and the sensor endows the sensor with better sensing performance and stability.

2. The structure of the amphiphilic polymer used in the present invention has strong designability and simple synthesis. Carbon nanotubes are cheap as an excellent conductive material. The combination of organic polymers and inorganic carbon nanotubes can effectively solve the problem of sensing coatings in sensors. Layer and performance stability issues, easy to realize industrial production and application.

3. The enzyme-free glucose sensor prepared by the present invention can have the advantages of fast response, wide detection range, high sensitivity and good stability.

4. The present invention rationally combines the science of polymer materials with the field of electrochemical sensing, and can be expanded and applied to the construction of other biological and chemical sensors on the basis of the application of glucose sensors, thereby being widely used in the fields of food safety, biomedicine, and life and health. .

Description of drawings

Figure 1: Schematic diagram of the preparation of the enzyme-free glucose sensor of the present invention;

Fig. 2: the digital photo of the solution of pure carbon nanotube (a) and polymer-carbon nanotube hybrid (b) in Example 1 of the present invention;

Figure 3: Transmission electron microscope image of the polymer-carbon nanotube hybrid prepared in Example 1 of the present invention;

Figure 4: Chronoamperometric curves of glucose detection by the enzyme-free glucose sensor in Example 1 of the present invention.

Detailed ways

The present invention will be further explained below in conjunction with specific embodiments, but the present invention is not limited to the conditions used in the following examples.

Example 1

A method for preparing an enzyme-free glucose sensor based on polymer-carbon nanotubes, characterized in that the preparation steps are as follows:

(1) Preparation of polymer-carbon nanotube hybrids

Dissolve the amphiphilic polymer in N,N-dimethylformamide to prepare a 5 mg/mL polymer solution, add carbon nanotubes, and disperse ultrasonically for 24 hours to obtain a uniformly dispersed amphiphilic polymer/carbon nanotube dispersion solution (the concentration of carbon nanotubes is 1 mg/mL); slowly drop ultrapure water into the dispersion for self-assembly, stir for 4 hours and dialyze for 2 days to obtain a polymer-carbon nanotube hybrid solution; pure carbon nanotubes (a ) and the polymer-carbon nanotube hybrid (b) solution digital photo as shown in Figure 2, it can be seen that pure carbon nanotubes gather at the bottom of the solution, while the polymer-carbon nanotube hybrid solution is Uniform ink color, showing good dispersion stability; and this result is also shown in transmission electron microscopy, as shown in Figure 3, the polymer is adsorbed on the surface of carbon nanotubes to prevent entanglement and agglomeration between carbon nanotubes, A bead-like structure was thus formed, indicating the successful preparation of the polymer-carbon nanotube hybrid.

(2) Construction of an enzyme-free glucose sensor

Pretreat the glassy carbon electrode, and pipette 10 μL of the polymer-carbon nanotube hybrid solution in step (1) on the glassy carbon electrode to obtain a polymer-carbon nanotube hybrid modified electrode, which is dried at room temperature and then immersed in In the silver nitrate solution, uniformly distributed silver nanoparticles were generated on the surface of the modified electrode by constant potential reduction of silver nitrate, the concentration of silver nitrate was 1mmol/L, the deposition voltage was -0.2V, and the deposition time was 90s, the enzyme-free glucose sensor was obtained. . Figure 4 is the chronoamperometry curve of the sensor detecting glucose. It can be seen that with the increase of glucose content, the current value increases linearly, indicating the successful construction of the enzyme-free glucose sensor.

Example 2

A method for preparing an enzyme-free glucose sensor based on polymer-carbon nanotubes, characterized in that the preparation steps are as follows:

(1) Preparation of polymer-carbon nanotube hybrids

Dissolve the amphiphilic polymer in N,N-dimethylformamide to prepare a 5 mg/mL polymer solution, add carbon nanotubes, and disperse ultrasonically for 24 hours to obtain a uniformly dispersed amphiphilic polymer/carbon nanotube dispersion solution (the concentration of carbon nanotubes is 1 mg/mL); slowly drop ultrapure water into the dispersion for self-assembly, stir for 4 hours and then dialyze for 2 days to obtain a polymer-carbon nanotube hybrid solution.

(2) Construction of an enzyme-free glucose sensor

The glassy carbon electrode is pretreated, and the polymer-carbon nanotube hybrid body in step (1) is electrodeposited on the electrode surface, the deposition voltage is 0.7V, and the deposition time is 5min to obtain a polymer-carbon nanotube hybrid After drying at room temperature, immerse in the silver nitrate solution, and generate uniformly distributed silver nanoparticles on the surface of the modified electrode through constant potential reduction of silver nitrate. The concentration of silver nitrate is 1mmol/L, the deposition voltage is -0.2V, and the deposition time is 90s, the enzyme-free glucose sensor is obtained.

Example 3

A method for preparing an enzyme-free glucose sensor based on polymer-carbon nanotubes, characterized in that the preparation steps are as follows:

(1) Preparation of polymer-carbon nanotube hybrids

Dissolve the amphiphilic polymer in N,N-dimethylformamide to prepare a 5 mg/mL polymer solution, add carbon nanotubes, and disperse ultrasonically for 24 hours to obtain a uniformly dispersed amphiphilic polymer/carbon nanotube dispersion solution (the concentration of carbon nanotubes is 2 mg/mL); ultrapure water was slowly dropped into the dispersion for self-assembly, stirred for 4 hours and then dialyzed for 2 days to obtain a polymer-carbon nanotube hybrid solution.

(2) Construction of an enzyme-free glucose sensor

The glassy carbon electrode is pretreated, and the polymer-carbon nanotube hybrid body in step (1) is electrodeposited on the electrode surface, the deposition voltage is 0.7V, and the deposition time is 5min to obtain a polymer-carbon nanotube hybrid The modified electrode was dried at room temperature and then immersed in silver nitrate solution. The uniform distribution of silver nanoparticles was generated on the surface of the modified electrode through constant potential reduction of silver nitrate. The concentration of silver nitrate was 1mmol/L, and the deposition voltage was -0.2V. The time is 90s, and the enzyme-free glucose sensor is obtained.

Claims (10)

1. a kind of preparation method based on polymer-carbon nanotube enzyme-free glucose sensor, it is characterised in that polymer-carbon is received Prepared by mitron hybrid, the structure of enzyme-free glucose sensor, is as follows：

(1) prepared by polymer-carbon nanotube hybrid：Amphiphilic polymers are dissolved in organic solvent, add in carbon nanotubes, are surpassed Sound disperses 1h~for 24 hours, obtains homodisperse amphiphilic polymers/carbon nano tube dispersion liquid；It is slowly dropped into dispersion liquid super Pure water, stirring 1h~for 24 hours, mixed liquor is then placed in dialysis 1d~7d in bag filter, obtains polymer-carbon nanotube hybrid Solution；

(2) structure of enzyme-free glucose sensor：Modified electrode is pre-processed, then by the polymer-carbon nanotube in step (1) Hydridization liquid solution is modified by the method for drop coating, spin coating or electrophoretic deposition to electrode surface, obtains polymer-carbon nanotube hydridization Body modified electrode, drying at room temperature；Then by the method for vacuum sputtering or electrochemical reduction metal nano catalyst precursor, The equally distributed metal nano catalyst particle of modified electrode Surface Creation is to get to enzyme-free glucose sensor.

2. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute It is block copolymer, graft copolymer, random copolymer, branched polymer, conjugated polymers to state amphiphilic polymers in step (1) One kind in object.

3. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute It is one kind in N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, dioxane to state organic solvent in step (1).

4. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute It is 0.1mg/mL~200mg/mL, amphiphilic polymers and carbon nanotubes matter to state the initial solubility of amphiphilic polymers in step (1) Amount is than being 1:0.01~1:1.

5. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute State the active force in step (1) between amphiphilic polymers and carbon nanotubes includes hydrogen bond action, electrostatic for non-covalent bond effect One or more of effect, π-π effects, coordination.

6. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute It is one kind in gold electrode, glass-carbon electrode, ITO electrode, carbon paste electrode to state modified electrode in step (2).

7. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute It is 0.1mg/mL~200mg/mL to state in step (2) amphiphilic polymers concentration in polymer-carbon nanotube hydridization liquid solution, double Parent's property polymer is 1 with carbon nanotube mass ratio:0.01~1:1.

8. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute Drop coating method is stated in step (2) to pipette the μ L polymer-carbon nanotubes hydridization liquid solution drop coatings of 5 μ L~30 in electrode surface, electricity Electrode is is immersed in polymer-carbon nanotube hydridization liquid solution by swimming deposition method, by controlling voltage and making to gather with the time Object-carbon nano-tube hybridization body modification is closed in electrode surface, specific electrophoretic deposition process condition is：Deposition voltage 0.5V~10V sinks Product time 1min~10min.

9. the preparation method of polymer-carbon nanotube enzyme-free glucose sensor according to claim 1, it is characterised in that institute It is Pt, Pb, Ni, Cu, Au, Ag, NiO, MnO to state metal nano catalyst in step (2)₂, one kind in CoO, ZnO, CuO.

10. according to the preparation method of polymer-carbon nanotube enzyme-free glucose sensor described in claim 9, metal nano is urged The preparation of agent derives from corresponding precursor solution, and precursor solution concentration is 0.01mmol/L~10mmol/L.