CN111326743A

CN111326743A - Application of porous carbon derived from bamboo as electrode material for glucose biosensing and glucose biofuel cell

Info

Publication number: CN111326743A
Application number: CN201911251420.6A
Authority: CN
Inventors: 胡宗倩; 许崔星
Original assignee: Institute of Pharmacology and Toxicology of AMMS
Current assignee: Institute of Pharmacology and Toxicology of AMMS; Academy of Military Medical Sciences AMMS of PLA
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2020-06-23

Abstract

The invention discloses application of porous carbon derived from bamboo as an electrode material for glucose biosensing and glucose biofuel cells. The composite material with the bamboo-derived porous carbon loaded with the glucose oxidase can be used for preparing a grape-like biosensor and a biofuel cell, and has great potential in the fields of glucose detection and electrochemistry.

Description

Application of porous carbon derived from bamboo as electrode material for glucose biosensing and glucose biofuel cell

Technical Field

The invention relates to the field of biomass materials, in particular to application of porous carbon derived from bamboo as an electrode material for glucose biosensing and glucose biofuel cells.

Background

Glucose oxidase (GOx) is an important dimeric protein, consisting of two identical 80-kda subunits, two Flavin Adenine Dinucleotide (FAD) cofactors are tightly bound and deeply embedded in the protein GOx is capable of specifically catalyzing β -D-glucose to D-gluconolactone, and thus has been widely used in the construction of glucose biosensors and enzymatic biofuel cells, as well as in the pharmaceutical and food industries₂. Then, oxygenFADH as the final electron acceptor₂Oxidized to FAD and simultaneously reduced to hydrogen peroxide. However, it is quite difficult to show the direct electron transfer behavior between GOx and bare electrode. This may be due to the fact that: the electrically active centers of GOx are buried in the molecular cavities, resulting in a large electron transport resistance.

Fortunately, the large surface area and unique electrical properties of nanomaterials can shorten the tunneling distance of electrons, thereby providing an electron relay function. To date, various nanomaterials, including conductive polymers, metal oxides, and carbon nanomaterials, have demonstrated the ability to increase the electron transport rate. Among them, carbon nanomaterials, particularly for graphene and Carbon Nanotubes (CNTs), have good compatibility, high conductivity, wide potential window and chemical inertness, thus drawing attention to immobilized enzymes and promotion of electron transfer. Although these reports indicate the potential of these nanomaterials in electroanalysis, there are still some drawbacks to consider. Relatively expensive and hazardous chemicals, complex equipment and complex synthetic procedures may prevent widespread commercialization in electrochemical analysis.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the present invention to propose the use of bamboo-derived porous carbon as an electrode material for glucose biosensing and glucose biofuel cells. The composite material with the bamboo derived porous carbon loaded with the glucose oxidase can be used for preparing a glucose-like biosensor and a biofuel cell, and has great potential in the fields of glucose detection and electrochemistry.

In one aspect of the invention, a composite material is provided. According to an embodiment of the invention, the composite material comprises: bamboo-derived porous carbon (B-dPC); glucose Oxidase (GO)_X) The glucose oxidase is loaded on the bamboo-derived porous carbon. In the composite material, bamboo derived porous carbon is obtained by carbonizing and pyrolyzing bamboo (Phyllostachys), has wide sources, is cheap and easy to obtain, contains rich defect sites,can be used as an excellent immobilized enzyme carrier material for the application of an electrochemical glucose sensor and a biofuel cell (BFC). GO fixed on B-dPC_XThe kit can show effective direct electron transfer behavior, and has high sensitivity, wide linear range and low detection limit for detecting glucose; B-dPC assembled glucose/O₂BFCs can produce high power densities and open circuit potentials and can extract energy directly from sugar solutions.

In addition, the composite material according to the above embodiment of the present invention may also have the following additional technical features:

according to an embodiment of the invention, the composite material further comprises: a crosslinking agent and a stabilizer.

According to an embodiment of the invention, the cross-linking agent is Glutaraldehyde (GA).

According to an embodiment of the invention, the stabilizer is a Nafion polymer.

In another aspect of the invention, the invention provides a method of making the composite material of the above embodiments. According to an embodiment of the invention, the method comprises: (1) carbonizing bamboo in inert gas atmosphere to obtain carbonized material; after acid washing, carrying out pyrolysis treatment on the carbonized material to obtain bamboo derived porous carbon; (2) mixing the bamboo-derived porous carbon with a solvent to obtain a bamboo-derived porous carbon dispersion liquid; applying the bamboo-derived porous carbon dispersion to the surface of a substrate, and then removing the solvent from the bamboo-derived porous carbon dispersion to form a porous carbon carrier layer; (3) mixing glucose oxidase with a buffer solution to obtain a glucose oxidase dispersion solution; applying the glucose oxidase dispersion to the porous carbon support layer to form an active component layer; (4) applying a crosslinker solution to the active component layer and then removing the solvent from the crosslinker solution; (5) applying a stabilizer solution to the active component layer to obtain the composite. The method is simple, convenient and efficient, is easy to implement industrially, and the prepared composite material has great potential in the fields of glucose detection and electrochemistry.

In addition, the method for preparing the composite material according to the above embodiment of the present invention may further have the following additional technical features:

according to the embodiment of the invention, the carbonization treatment can be carried out at 700-900 ℃. Specifically, before carbonizing the bamboo, the bamboo can be washed and cut into small strips, dried at 40-70 ℃ for 10-14 h, and then carbonized, wherein the temperature of the carbonization treatment can be 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃ and the like, and the heating rate can be 5 ℃ and min^-1。

According to the embodiment of the invention, the acid washing treatment can be completed by using hydrochloric acid at 70-85 ℃ for 10-15 hours. Specifically, the temperature may be 70 ℃, 75 ℃, 80 ℃, 75 ℃ or the like, the time of the reaction may be 10 hours, 12 hours, 14 hours, 15 hours or the like, and the concentration of hydrochloric acid may be 3M, whereby inorganic impurities in the material can be effectively removed.

According to the embodiment of the invention, the pyrolysis treatment can be completed at 1500-1700 ℃ for 1-3 h. The pyrolysis treatment temperature can be 1500 deg.C, 1550 deg.C, 1600 deg.C, 1650 deg.C, 1700 deg.C, etc., and the heating rate can be 5 deg.C/min^-1The pyrolysis time can be 1h, 2h, 3h, etc.

According to the embodiment of the invention, the concentration of the bamboo-derived porous carbon dispersion liquid is 10-30 mg-mL^-1。

According to the embodiment of the invention, the concentration of the glucose oxidase dispersion liquid is 20-40 mg/mL^-1。

According to an embodiment of the invention, the volume ratio of the bamboo-derived porous carbon dispersion to the glucose oxidase dispersion is (2-4): 1. Thus, the loading effect of the glucose oxidase on the bamboo-derived porous carbon can be further improved, and the performance of the obtained composite material can be further improved.

In another aspect of the present invention, the present invention provides a glucose biosensor. According to an embodiment of the present invention, the glucose biosensor includes: an electrode base body; the composite material of the above embodiment, which is formed on the electrode base body. The glucose biosensor has a concentration of 42.9. mu.A.mM^-1·cm^-2High sensitivity, wide linear range of 0.01-3.86 mM and low detection limit of 1.2 mu M, and shows great glucose detection possibility in medical glucose injection and sugar-containing soft drinks.

In addition, the glucose biosensor according to the above embodiment of the present invention may further have the following additional technical features:

according to an embodiment of the invention, the electrode substrate is a Glassy Carbon Electrode (GCE).

In another aspect of the invention, a biofuel cell is provided. According to an embodiment of the present invention, the biofuel cell comprises: a bioanode and a biocathode, wherein the bioanode comprises a current collector and an anode active component, and the anode active component is the composite material of the embodiment; the biocathode comprises a current collector and a cathode active component, wherein the cathode active component comprises bamboo-derived porous carbon and laccase, and the laccase is loaded on the bamboo-derived porous carbon. The biofuel cell can produce 192 μ W cm^-2High power output and an open circuit potential of 0.76V, energy can be directly harvested from different sugar-containing soft drinks.

according to an embodiment of the invention, the current collector is nickel foam.

According to an embodiment of the present invention, the cathode active component further comprises: a stabilizer.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a graph of the results of characterization of bamboo-derived porous carbon (B-dPC), wherein A is an SEM image of B-dPC; b is a TEM image of B-dPC; c is the XRD pattern of B-dPC; d is the Raman spectrum of B-dPC, E is the XPS spectrum of B-dPC, and the inset is the O1s spectrum of B-dPC; f is the FT-IR spectrum of B-dPC;

FIG. 2 is a graph showing the results of electrochemical activity test of B-dPC/GCE, wherein A is 5mM K containing 0.1M KCl₃[Fe(CN)₆Cyclic Voltammograms (CV) of GCE (a) and B-dPC/GCE (B), sweep rate: 10mV s-1; b is in the presence of 0.1MKCl at 5mM [ Fe (CN)₆]^3-/4-The Nyquist plots at GCE (c) and B-dPC/GCE (d) in (1);

FIG. 3 is a graph showing the results of direct electrochemical measurements of glucose oxidase (GOx) on B-dPC/GCE electrodes, wherein A is Nafion/GA/GCE (a), Nafion/GA/GOx/GCE (B), Nafion/GA/B-dPC/GCE (c) and Nafion/GA/GOx/B-dPC/GCE (d) at 50 mV. s^-1Saturated with Ar at 0.1M CV in PBS at pH 7.0; b is the CV of Nafion/GA/GOx/B-dPC/GCE in Ar-saturated 0.1M PBS (pH 7.0) at a scan rate of from 50 mV. multidot.s^-1To 600 mV. s^-1(ii) a C is the relationship between current and scan rate; d is E_pRelationship to Ln v; e is the CV of Nafion/GA/GOx/B-dPC/GCE in Ar-saturated 0.1M PBS at various pH values; f is a correlation curve of E' 0 to the pH value of the electrolyte;

FIG. 4 is a graph of the results of characterization of a glucose biosensor, where A is the CV of Nafion/GA/GOx/B-dPC/GCE in Ar (a) and air saturation (B)0.1M pH7.0PBS, scan rate: 50 mV. s^-1(ii) a (B) CV for Nafion/GA/GOx/B-dPC/GCE in 0.1M pH7.0PBS in the absence (d) and in the presence (c) of 10mM glucose; c is the current response to continuous addition of GLU at Nafion/GA/GOx/B-dPC/GCE; d is the calibration curve for GLU at Nafion/GA/GOx/B-dPC/GCE, inset: Lineweaver-Burk type plot for electrochemical determination of the apparent Michaelis-Menten constant of Nafion/GA/GOx/B-dPC/GCE; e is the Ampere response to the sequential addition of 1.0mM GLU, 0.1mM DA, 0.1mM UA, 0.1mM AA, 0.1mM L-cys and 0.1mM APAP at Nafion/GA/GOx/B-dPC/GCE; f is the stability of the amperometric response to 0.5mM GLU on Nafion/GA/GOx/B-dPC/GCE; electrolytes in panels C, E and F: 0.1M pH7.0PBS, applied potentials of panels C, E and F: -0.45V;

FIG. 5 is a B-dPC based doughElectrochemical reduction of O on a material cathode₂Wherein A is a CV curve of Nafion/Lac/B-dPC/GCE biocathode in an Ar-saturated 0.04M BR solution (pH5.0) in the absence of ABTS (a) and in the presence of 0.5mM ABTS (B), and Nafion/Lac/B-dPC/GCE biocathode in O containing 0.5mM ABTS₂CV curve (c) in saturated 0.04MB-R solution (pH 5.0); b shows a schematic diagram and an operating mechanism of the designed BFC; c shows the dependence of power density on cell voltage; d shows stability of power output of BFC operating continuously at + 0.51V;

FIG. 6 is a B-dPC based glucose/O₂Energy output profile of a biofuel cell (BFC) where a is orange juice and B is coca-cola.

Detailed Description

The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

In the present invention, bamboo (Phyllostachys) is available in Beijing, China. Soda water with orange fruit and coca cola brands was purchased from coca cola, inc. Commercially available glucose injections were purchased from Jilin Huapasture animal health products, Inc. (China). Glucose oxidase (GOx, EC 1.1.3.4, initial activity: 200U. mg^-1) From Sigma-Aldrich, Ascorbic Acid (AA), N, N-Dimethylformamide (DMF) and Uric Acid (UA) from national drug-controlled chemical Limited Nafion solution (5 wt.% in a mixture of 15-20% lower aliphatic alcohol and water), 2,2' -azidobis (3-ethylbenzothiazoline-6-sulfonic Acid) (ABTS), glutaraldehyde (GA, 50%), acetaminophen (APAP), Dopamine (DA) and cysteine (L-cys) from Azadine, Nickel foam from a source of force Anhydrous α -D- (+) -glucose from Acros Organics, Nafion 117 membrane and laccase (Lac, ≧ 4.0U. mg^-1) Purchased from Alfa-Aesar. All reagents are of analytical reagent grade, without the need forFurther purifying for direct use.

In the present invention, Cyclic Voltammetry (CV), amperometry and Linear Sweep Voltammetry (LSV) were performed on a CHI 660C electrochemical workstation (chenhua instruments ltd, china). Electrochemical measurements were performed using a standard three-electrode configuration with a Glassy Carbon Electrode (GCE), a platinum sheet, and an Ag/AgCl (saturated KCl) electrode as the auxiliary electrode and auxiliary electrode, respectively. The WITec CRM200 instrument using a 532nm laser provides raman spectra. X-ray photoelectron spectroscopy (XPS) data was collected using a Thermo Scientific Escalab 250 spectrometer. The PANALYtic X' pert Pro X-ray diffractometer provided the diffraction data. SEM images were obtained using a JSM-6701 field emission Scanning Electron Microscope (SEM). The Micromeritics ASAP2020HD analyzer provides nitrogen adsorption-desorption data. Fourier transform Infrared Spectroscopy (FT-IR) spectra were obtained from Spectrum 100FT-IR obtained from Perkin Elmer.

Example 1

Preparation of bamboo-derived porous carbon (B-dPC)

First, fresh bamboo is rinsed with deionized water and cut to size (about 3 × 1 × 0.5.5 cm)³) Then dried in an oven (60 ℃) for 12 h. Drying bamboo in Ar atmosphere at 800 deg.C (5 deg.C. min)^-1) After carbonization in a tube furnace, the product was thoroughly treated with HCl (3M) at 80 ℃ for 12h to remove inorganic impurities. Finally, the dried sample was transferred again to a tube furnace and subjected to Ar atmosphere at 5 ℃ for min^-1Pyrolysis was carried out at 1600 ℃ for 2 h. The final product is designated B-dPC.

Example 2

Preparation of glucose biosensor

(1) GCE was polished on a polishing cloth with 0.05 μm alumina powder. After sequential sonication in dilute nitric acid solution, ethanol and deionized water, the cleaned electrode was dried in air. A homogeneous dispersion (20 mg. multidot.mL) was prepared by dissolving 20mg of B-dPC in 1mL of DMF by sonication^-1). After that, 6 μ L of the dispersion was dressed onto clean GCE. After evaporation of the solvent under infrared light, B-dPC/GCE was obtained.

(2) mu.L GOx solution (31.8 mg. mL)^-1Prepared by 0.1M pH 7.2 PBS) to B-dPC/GCE (denoted as GOx/B-dPC/GCE). To crosslink GOx onto B-dPC/GCE, 3. mu.L of GA solution (0.5% (w/v) in deionized water) was further spread on the surface of GOx/B-dPC/GCE (denoted as GA/GOx/B-dPC/GCE). The product was allowed to dry naturally for 2 hours. Finally, 2 μ L of a 0.5 wt.% Nafion solution was uniformly dispersed on the electrode surface to maintain its stability (expressed as Nafion/GA/GOx/B-dPC/GCE).

For comparison, Nafion/GA/GCE, Nafion/GA/GOx/GCE and Nafion/GA/B-dPC/GCE were prepared in a similar manner.

Example 3

Preparation of biofuel cell

glucose/O was prepared in two compartments separated by a Nafion 117 membrane using Nafion/GA/GOx/B-dPC/Ni foam as the bioanode and Nafion/Lac/B-dPC/Ni foam as the biocathode₂And (4) BFC. The bioanode was immersed in 0.1M pH5.0 PBS containing 10mM glucose and O containing 0.5mM ABTS₂A saturated 0.04M solution pH5.0 Britton-Robinson (B-R) was used as catholyte. glucose/O₂BFC Performance is measured by two-electrode LSV (2mV s)^-1) Evaluation was performed.

Foamed nickel treated with acetone and 3M HCl was used as current collectors for the preparation of bioanodes and biocathodes for biofuel cells (BFC).

To prepare the bioanode, 100 μ L B-dPC suspension was spread onto pre-treated Ni foam (denoted B-dPC/Ni foam). After drying under an infrared lamp, 30 μ LGOx solution was pipetted onto the B-dPC/Ni foam surface. Then, 50. mu.L of GA solution was further modified on the surface of GOx/B-dPC/Ni foam and dried in air for 2 h. Finally, 30 μ L of an Afion solution was dropped onto the surface and dried in air (denoted as Nafion/GA/GOx/B-dPC/Ni foam).

To prepare a biocathode, similarly, 100 μ L of B-dPC suspension was slowly spread over the surface of the Ni foam and dried under infrared light irradiation (denoted B-dPC/Ni foam). Then, 50. mu.L of Lac solution (20 mg. mL) was added^-1Prepared by 0.04M pH 5.0B-R) was spread on the B-dPC/Ni foam surface, and electrodes were placedDried at room temperature for 2h (expressed as Lac/B-dPC/Ni foam). Finally, the electrode was coated with 30. mu.L of Nafion solution and dried at room temperature (denoted as Nafion/Lac/B-dPC/Ni foam).

Test example 1

Characterization of bamboo-derived porous carbon (B-dPC)

The morphological observation of B-dPC was first verified using a Scanning Electron Microscope (SEM). In FIG. 1A, B-dPC maintained the vascular bundle structure of bamboo, which may facilitate the transport of electrolyte. Pores of about 1 μm size were found in the cross-section of B-dPC and were aligned (FIG. 1A inset). The pores of B-dPC were further characterized by Transmission Electron Microscope (TEM) measurements, as shown in FIG. 1B. To reveal structural information of B-dPC, the nanomaterials were characterized using X-ray diffraction (XRD) (FIG. 1C). In that

And

there are two characteristic peaks in the vicinity, due to the (002) and (100) planes of graphite, respectively. Raman spectroscopy was further determined to obtain structural and topological information of B-dPC. In FIG. 1D, the Raman spectrum of B-dPC reveals D (located at

At) and G-band (located at

At) due to sp²Lattice distortion in the domains and E_2gRespectively sp of²C ═ C bond. In addition, the intensity ratio (I) of the D band to the G band_D/I_G) The degree of structural defects may be reflected. I of B-dPC_D/I_GThe ratio was calculated to be 1.27, higher than mesoporous carbon (0.700) and carbon nanotubes (0.74). This indicates that B-dPC contains a high density of defect sites, which may improve electrochemical activity.

Test example 2

Electrochemical activity

Firstly, get throughThe electrochemical activity of B-dPC modified GCE (B-dPC/GCE) was determined by cyclic voltammetry (5 mM K with 0.1M KCl₃[Fe(CN)₆]) (FIG. 2A). The well-defined redox peak (B) observed on B-dPC/GCE had a lower peak-to-peak separation (. DELTA.Ep) than GCE (78mV, a), indicating that B-dPC/GCE had a faster electron transfer rate than GCE. According to the Randles-Sevcik equation, the sum of the linear velocity and the linear velocity of the linear velocity is 0.075cm²The GCE of (1) has a larger electroactive area of 0.096cm than that of B-dPC/GCE². To better understand the electron transfer capability of B-dPC/GCE, Electrochemical Impedance Spectroscopy (EIS) was used to estimate the charge transfer resistance (Rct) of the different electrodes. Rct values are equal to the diameter of the semicircular part of the EIS curve. As shown in FIG. 2B, the Rct value (69.2 Ω, d) of B-dPC/GCE was lower than that of GCE (314.3 Ω, c), which means that B-dPC promoted electron transfer between the electrolyte and GCE.

Test example 3

Direct electrochemistry of glucose oxidase (GOx) on B-dPC/GCE electrodes

The direct electrochemical behavior of GOx on Nafion/GA/GOx/B-dPC/GCE was studied using cyclic voltammetry. FIG. 3A shows Cyclic Voltammograms (CV) performed in Ar-saturated 0.1M Phosphate Buffered Saline (PBS) at a scan rate of 50 mV. multidot.s^-1. Obviously, the CVs of Nafion/GA/GCE, Nafion/GA/GOx/GCE and Nafion/GA/B-dPC/GCE are only squares due to the presence of the double layer capacitance. The CV background current for Nafion/GA/B-dPC/GCE was significantly greater compared to Nafion/GA/GCE and Nafion/GA/GOx/GCE, indicating that the use of high surface area B-dPC may facilitate its increase. No redox peaks were observed on the three electrodes, indicating that these electrodes are electrochemically inert. In contrast, Nafion/GA/GOx/B-dPC/GCE showed a pair of significant redox peaks with a formal potential of-0.458V, comparable to the previously reported FAD/FADH with pH7.0₂The data for the redox centers are similar. The results clearly show the Direct Electron Transfer (DET) capability of GOx on Nafion/GA/GOx/B-dPC/GCE. Furthermore, the peak-to-peak separation of Nafion/GA/GOx/B-dPC/GCE was 36mV, and the cathode peak current was approximately equal to the anode current, indicating that GOx was immobilized on Nafion/GA/GOx/B-dPC/GCEQuasi-reversible electrochemical processes.

To further evaluate the DET characteristics of GOx on Nafion/GA/GOx/B-dPC/GCE, the effect of scan rate on voltammetric response was investigated. As shown in FIG. 3B, Nafion/GA/GOx/B-dPC/GCE was at 50 to 600 mV. multidot.s^-1Shows a clear DET characteristic at the scanning rate. The redox peak current is linear with scan rate (fig. 3C), indicating that the electrochemical reaction of GOx is a surface-limited process. In FIG. 3D, the cathode and anode peak potentials of Nafion/GA/GOx/B-dPC/GCE are slightly shifted in the negative and positive directions, respectively. The scanning speed is higher than 150 mV.s^-1While the peak potential is linearly related to the log of the scan rate, and the slope of the potential with respect to ln v is equal to RT/(1- α) nF and-RT/α nF. based thereon, α can be calculated as 0.49 the electron transport rate constant (ks) of GOx at Nafion/GOx/B-dPC/GCE is calculated as 5.43s with the aid of the Laviron equation for the surface control process^-1. This value is significantly greater than previously reported immobilization on pCoTTP-SWNTs/GCE (1.01 s)^-1) graphene/SWCNT cogel electrode (0.23 s)^-1) Value of GOx on AuNPs-MWCNTs-PVA film (2.2 s)^-1)，GCE/RGO(4.8s^-1) And porous TiO₂Electrode (3.96 s)^-1). This means that B-dPC can greatly facilitate electron transfer between GOx and the electrode. DET in GOx is a 2 proton and 2 electron transfer process, and thus DET properties will be affected by buffer pH. As follows:

FIG. 3E shows Nafion/GA/GOx/B-dPC/GCE with CV's at different pH values in Ar-saturated 0.1M PBS. As shown, the electrodes showed a pair of well-defined GOx redox peaks in each buffer. In addition, an increase in buffer pH from 5.0 to 9.0 resulted in a negative shift in both the cathodic and anodic peaks. In addition, as shown in FIG. 3F, the formal potential was found to be linearly related to the pH of the buffer, with a slope of-57.1 mV/pH. The slope is close to the theoretical Nernst value of-58.6 mV/pH, indicating that the double proton coupled double electron process participates in the electrochemical process of GOx.

Test example 4

Glucose biosensors are very important in clinical diagnostics and biotechnology applications. Nafion/GA/GOx/B-dPC/GCE can be considered as a very advantageous electrode for the fabrication of highly sensitive and selective biosensors due to its advantages of relatively negative redox potential (-0.458V, pH 7.0) and enhanced electron transfer capability. FIG. 4A compares Nafion/GA/GOx/B-dPC/GCE at 50mV s^-1Ar- (curve a) and air saturated (curve b) CV in 0.1M pH7.0 PBS. As shown, a larger reduction peak current and a lower oxidation peak current can be found in the air-saturated solution than in the Ar-saturated solution. The results may be attributed to a reductase on the electrode (GOx-FADH)₂) Can be rapidly oxidized by oxygen in an air-saturated solution as follows:

GOx-FADH₂+O₂→GOx-FAD+H₂O₂

notably, catalytic regeneration of GOx to the oxidized form (GOx-FAD) resulted in a loss of curve reversibility. Furthermore, the addition of 10mM glucose to an air-saturated solution resulted in a decrease in the reduction peak current of Nafion/GA/GOx/B-dPC/GCE (FIG. 4B, where curves c and d are the CVs of Nafion/GA/GOx/B-dPC/GCE in 0.1M PBS pH7.0, in the presence and absence of 10mM glucose, respectively). This can be explained by the occurrence of enzyme catalysis. According to the equation, the reaction between GOx-FAD and glucose is shown below:

Glucose+GOx-FAD→Gluconolactone+GOx-FADH₂

the biosensing application of Nafion/GA/GOx/B-dPC/GCE to glucose was evaluated amperometrically at-0.45V based on the excellent electrochemical performance of Nafion/GA/GOx/B-dPC/GCE in glucose electrooxidation. FIG. 4C shows the current time curves for different glucose concentrations in 0.1M pH7.0PBS saturated with magnetically stirred air at Nafion/GA/GOx/B-dPC/GCE. As shown, a clear response was found with each glucose injection. The calibration curve depicted in FIG. 4D shows a linear range (R) of 0.01 to 3.86mM²0.996), sensitivity 42.9 μ AmM^-1cm^-2The detection limit was 1.2. mu.M (S/N-3). Root of herbaceous plantAccording to the Lineweaver-Burk plot (FIG. 4D inset), the apparent Michaelis-Menten constant (Km, app) determined as an indicator of the kinetics of the enzyme substrate reaction was 1.7 mM. Km, app value was significantly less than GOx/single-walled carbon nanohorn (8.5mM) and GOx/Pt @ MZF-1(6.1 mM). The smaller Km, the app value, indicates that Nafion/GA/GOx/B-dPC/GCE has a significant affinity for glucose.

Nafion/GA/GOx/B-dPC/GCE also has higher selectivity for glucose detection. As shown in fig. 4E, the injection of 0.1mM interferents, such as Uric Acid (UA), Ascorbic Acid (AA), Dopamine (DA), acetaminophen (APAP) and L-cysteine (L-cys) to the electrolyte was negligible in current change, whereas a significant current change was observed with the addition of 1.0mM glucose. To evaluate its antifouling capacity, the antifouling capacity of Nafion/GA/GOx/B-dPC/GCE was determined by evaluating the current time response of 0.5mM glucose. As shown in FIG. 4F, the current response at Nafion/GA/GOx/B-dPC/GCE remained 95.3% of the initial response after 10000s, indicating that the antifouling capacity of Nafion/GA/GOx/B-dPC/GCE was high. In addition, after Nafion/GA/GOx/B-dPC/GCE was stored at 4 ℃ for 2 weeks, its current response to 1mM glucose was still 96.9% of its original response, indicating a long shelf life. Repeatability was also investigated by measuring the current response at 0.5mM glucose at five Nafion/GA/GOx/B-dPC/GCE. The relative standard deviation was determined to be 1.8%, indicating that Nafion/GA/GOx/B-dPC/GCE has excellent reproducibility. The high performance glucose detection capability of Nafion/GA/GOx/B-dPC/GCE makes it a great potential in determining the glucose content in real samples. Glucose content of commercial glucose injections and soft drinks was analyzed using Nafion/GA/GOx/B-dPC/GCE using standard addition methods and the results are shown in Table 1. The recovery was between 95.8% and 103.1%, indicating: Nafion/GA/GOx/B-dPC/GCE has great potential in sensitive and practical glucose determination. In particular, the glucose concentration in the commercial glucose injection measured by Nafion/GA/GOx/B-dPC/GCE matched well with the concentration provided by the company, indicating that the accuracy of glucose detection in Nafion/GA/GOx/B-dPC/GCE was very high.

TABLE 1 detection of glucose in real samples

Test example 5

Electrochemical reduction of O on B-dPC-based biocathodes₂

Considering that DET between the active center of laccase (Lac) and the electrode is difficult to achieve due to strict enzyme orientation and relatively complicated reaction mechanism, electron transfer between Lac and the electrode is mediated using 2,2' -azidobis (3-ethylbenzothiazoline- (6-sulfonic Acid) (ABTS) FIG. 5A shows CV recorded in Nafion/Lac/B-dPC/GCE, ar saturation (B) and oxygen saturation with 0.5mM ATBTS (c)0.04M pH5.0 Britton-Robinson (B-R) solution for comparison, studies were performed without ABTS, the current response of the biocathode in Ar saturated solution (a) as shown, when the electrolyte is saturated with Ar, there is a pair of distinct redox peaks only in the presence of abts (b), this is representative of the electrocatalytic properties of ABTS in O containing 0.5mM ABTS.₂In the saturated solution (c), a higher reduction current than that of the Ar saturated solution (b) can be found. This suggests that electron transfer between the redox site of Lac and the electrode can be mediated by ABTS.

Test example 6

Assembled B-dPC-based glucose/O₂Performance of biofuel cell (BFC)

As described above, Nafion/Lac/B-dPC/GCE and Nafion/GA/GOx/B-dPC/GCE respectively showed excellent results against O₂Electrochemical activity of reduction and glucose oxidation. These advantages make B-dPC a means to construct high performance glucose/O₂Ideal selection of BFC. The BFC consists of a Nafion/GA/GOx/B-dPC/Ni foam biological anode and a Nafion/Lac/B-dPC/Ni foam biological cathode. FIG. 5B shows glucose/O equipped with B-dPC electrodes₂Schematic of BFC. Figure 5C shows the power output density versus cell voltage (P-V curve) for the assembled BFC. As expected, the open circuit voltage and maximum power density at 0.51V for the assembled BFC were 0.76V and 193 μ W-cm, respectively^-2. After BFC was discharged continuously at room temperature for 12 hours, it retained 73.8% of its initial power,this indicates that the assembled BFC is relatively stable (fig. 5D). In addition, the ability of the assembled BFC to harvest energy from commercial soft drinks was further investigated. Glucose-rich soft drinks are considered glucose/O because of their green, available and low cost characteristics₂BFC, suitable fuels. Fig. 6A-B show power-voltage curves by using as fuel a mixture of soft drink and 0.1M PBS (pH5.0) in a ratio of 1:4(v: v). If orange juice or Coca Cola is used as fuel, the OCP of BFC is almost the same, and the maximum power density of BFC is 96.2 or 113.7 μ W-cm, respectively^-2. The excellent power output of replacing soft drinks with glucose can be explained by relatively high glucose levels and complex ingredients. Therefore, BFCs equipped with B-dPC can generate energy directly from commercial soft drinks.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A composite material, comprising:

bamboo-derived porous carbon;

glucose oxidase supported on the bamboo-derived porous carbon.

2. The composite material of claim 1, further comprising: a crosslinking agent and a stabilizer;

optionally, the cross-linking agent is glutaraldehyde;

optionally, the stabilizer is a Nafion polymer.

3. A method of making the composite material of claim 1 or 2, comprising:

(1) carbonizing bamboo in inert gas atmosphere to obtain carbonized material; after acid washing, carrying out pyrolysis treatment on the carbonized material to obtain bamboo derived porous carbon;

(2) mixing the bamboo-derived porous carbon with a solvent to obtain a bamboo-derived porous carbon dispersion liquid; applying the bamboo-derived porous carbon dispersion to the surface of a substrate, and then removing the solvent from the bamboo-derived porous carbon dispersion to form a porous carbon carrier layer;

(3) mixing glucose oxidase with a buffer solution to obtain a glucose oxidase dispersion solution; applying the glucose oxidase dispersion to the porous carbon support layer to form an active component layer;

(4) applying a crosslinker solution to the active component layer and then removing the solvent from the crosslinker solution;

(5) applying a stabilizer solution to the active component layer to obtain the composite.

4. The method according to claim 3, wherein the carbonization treatment is performed at 700 to 900 ℃;

optionally, the acid cleaning treatment is completed by hydrochloric acid at 70-85 ℃ for 10-15 h;

optionally, the pyrolysis treatment is carried out at 1500-1700 ℃ for 1-3 h.

5. According to claim 3The method is characterized in that the concentration of the bamboo-derived porous carbon dispersion liquid is 10-30 mg/mL^-1；

Optionally, the concentration of the glucose oxidase dispersion is 20-40 mg/mL^-1。

6. The method according to claim 3, wherein the volume ratio of the bamboo-derived porous carbon dispersion to the glucose oxidase dispersion is (2-4): 1.

7. A glucose biosensor, comprising:

an electrode base body;

the composite material of claim 1 or 2, formed on the electrode substrate.

8. The glucose biosensor of claim 1, wherein the electrode substrate is a glassy carbon electrode.

9. A biofuel cell, comprising: a bioanode and a biocathode, wherein,

the bioanode comprising a current collector and an anode active component, the anode active component being the composite of claim 1 or 2;

the biocathode comprises a current collector and a cathode active component, wherein the cathode active component comprises bamboo-derived porous carbon and laccase, and the laccase is loaded on the bamboo-derived porous carbon.

10. The biofuel cell of claim 9 wherein the current collector is a nickel foam;

optionally, the cathode active component further comprises: a stabilizer;

optionally, the stabilizer is a Nafion polymer.