CN115097149A - Method for simultaneously detecting glucose and cholesterol, electrode and electrode manufacturing method - Google Patents

Abstract

The invention discloses a Ti based on MXene material ₃ C ₂ T _x The enzyme-free screen printing electrode SPE for simultaneously detecting the glucose and the cholesterol and the manufacturing method thereof can be used for simultaneously detecting the glucose and the free cholesterol in a human blood sample. The electrode is prepared by combining screen printing with an electrochemical deposition technology, and a working electrode, a counter electrode and a reference electrode are combined on a PET substrate, wherein the working electrode is MXene/carbon C/chitosan CTS/cuprous oxide Cu ₂ O, the reference electrode is silver Ag/silver chloride AgCl, the counter electrode is C, and the test can be completed by only a small amount of the solution to be tested. Oxidation of glucose, Cu at Positive potential Using MXene ₂ And oxidizing cholesterol by O at a negative potential, simultaneously detecting multiple substances by using electrochemical testing technologies such as a time-current method it and the like, and testing in a real human blood sample to prove the detection feasibility of the substances.

Description

Method for simultaneously detecting glucose and cholesterol, electrode and electrode manufacturing method

Technical Field

The invention relates to the technical field of blood sugar and cholesterol detection, in particular to a method for simultaneously detecting glucose and cholesterol, a detection electrode and an electrode manufacturing method.

Background

Glucose is an important biological index, plays an important role in the field of biology, is a main energy supply substance of organisms, is an energy source and a metabolic intermediate product of living cells, and is related to diabetes, renal dysfunction and failure existing in human blood and the like.

Currently, there is no effective treatment for these diseases, and therefore, rapid and accurate blood glucose detection is crucial to the treatment and control of diabetes and the like. Meanwhile, the incidence of 'three highs', namely hyperglycemia, hypertension and hyperlipidemia, rapidly rises in the world, belongs to 'rich diseases' derived from the rapid development of times, and has certain relevance, for example, a diabetic is susceptible to hyperlipidemia, arteriosclerosis is easily formed, the poor elasticity of blood vessels of the diabetic is aggravated, and the blood pressure is increased, so that the 'three highs' can be caused by any one of the three diseases. Meanwhile, diabetes easily causes atherosclerotic cardiovascular disease complications such as heart failure, myocardial infarction, peripheral vascular occlusion, cerebral apoplexy and the like, and seriously affects the life quality and life expectancy of diabetic patients. The large-scale biochemical analyzer can complete simultaneous detection, but wastes time and labor, and needs to depend on professional operators, thereby bringing inconvenience to long-term frequent reexamination of chronic diseases and being not beneficial to early discovery and early diagnosis of diseases. Therefore, the accurate, stable and low-cost biosensor for synchronously detecting the glucose and the cholesterol is researched and developed, the concentration and the dynamic change trend of the glucose and the cholesterol are monitored, the compliance of daily tests of patients is improved, and the biosensor has important research values in prevention, diagnosis and treatment and screening of various diseases.

At present, two methods, namely an electrochemical method and an optical method, are mainly used for measuring glucose, cholesterol and other small biological molecules.

The optical measurement method has the advantages of non-invasiveness, but has poor anti-interference performance, weak signal, high uncertainty and complex operation, and is not suitable for preparing portable household sensors.

Electrochemical methods have become increasingly effective and important detection methods due to their unique advantages, including high sensitivity, high detection efficiency, simple instrument, easy operation, low production cost, and the like. The electrochemical glucose sensor electrode is characterized in that glucose oxidase (GOx) or Glucose Dehydrogenase (GDH) is modified on the electrode to serve as a sensitive unit, cholesterol oxidase (ChOx) is mainly utilized by the cholesterol sensor, the enzyme-containing sensor has the advantages of good specificity, high accuracy and the like, and the activity of the enzyme is sensitive to the environment and is easily influenced by factors such as pH value, humidity, toxic chemical substances and the like.

Therefore, the enzyme-free electrochemical glucose/cholesterol sensor with high detection index, low cost and strong applicability is developed, the dependence of detection on environmental factors is eliminated, and the enzyme-free electrochemical glucose/cholesterol sensor has extremely high research value and wide application prospect.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aims to solve the problems in the prior art and provide a method for simultaneously detecting glucose and cholesterol, an electrode and a manufacturing method of the electrode.

The invention provides the following technical scheme: the invention discloses a method for detecting glucose and cholesterol simultaneously, which uses Ti4+ in MXene to oxidize glucose at a positive potential, uses Cu2+ generated by Cu2O at a negative potential to oxidize cholesterol, and realizes enzyme-free simultaneous detection of glucose and cholesterol by the synergistic action of the MXene and the Cu 2O.

Further, through the synergistic effect of the MXene and the Cu2O, the generated reaction current is output to a sensing detection end through a microelectrode, and concentration information is output in real time through establishing a correlation model of blood sugar/cholesterol concentration and an electrical signal

The invention also discloses an electrode for simultaneously detecting and detecting glucose and cholesterol, wherein the electrode is MXene/CTS/Cu ₂ The O/SPCE electrode comprises an insulating layer, a PET substrate, and an Ag/AgCl reference electrode, a C counter electrode and MXene/CTS/Cu integrated on the PET substrate ₂ An O/C working electrode.

The invention also discloses a manufacturing method of the electrode for detecting and detecting glucose and cholesterol, which comprises the steps of preparing MXene solution, mixing the MXene solution with carbon paste, and modifying the mixture on SPC (specific protein chip) through screen printingE, obtaining MXene/SPCE in the defined working electrode area; subsequent electrodeposition of cuprous oxide Cu on the MXene/SPCE ₂ Performing O treatment to obtain MXene/CTS/Cu ₂ And (3) an O/SPCE electrode.

Further, the method comprises the following steps of,

s1: etching an Al layer in MAX by using a hydrothermal method to generate a layered two-dimensional nano material to prepare an MXene solution;

s2: mixing the MXene solution with carbon slurry, modifying a working electrode area defined on the SPCE through screen printing, and drying to obtain an MXene/SPCE electrode;

s3: under constant potential, the MXene/SPCE electrode is subjected to electrodeposition of cuprous oxide Cu ₂ Performing O treatment to obtain MXene/CTS/Cu ₂ O/SPCE electrodes.

Further, the step S1 specifically includes the following steps,

s1.1, 1 g of lithium fluoride is added to 20 mL of 9M aqueous hydrochloric acid solution, and then 1 g of Ti is slowly added over 10min ₃ AlC ₂ Then transferring the mixture into a 35 ℃ water bath for treatment for 24 h, centrifuging at 3500 rpm for 10min, and pouring off the supernatant;

s1.2, washing the mixture precipitate after the supernatant is removed with deionized water, putting the mixture precipitate into a high-power ultrasonic machine for ultrasonic treatment for 10min, taking out the mixture for continuous centrifugation, and repeating the step for multiple times until the pH value of the supernatant poured out after centrifugation reaches 5;

s1.3, adding ethanol as an intercalation agent into the centrifuge tube, respectively carrying out ultrasonic treatment and centrifugation on the dispersion for 1 hour, wherein the ultrasonic power is 750W, and the centrifugation parameter is 10000 rpm;

s1.4, adding deionized water into the centrifugal precipitation product, continuing to perform ultrasonic treatment for 20 min at 750W power, then centrifuging the dispersion liquid for 3 min at 3500 rpm, and collecting the black brown supernatant as MXene solution.

Further, the S2 specifically includes the following steps:

s2.1, cutting the PET film into a proper size, cleaning with ethanol and deionized water, and drying; then, the membrane is placed in a working area of a screen printing machine, and a vacuum pump is started to enable the membrane to be tightly attached to the surface of the machine and ensure that no air bubbles exist;

s2.2, fully aligning the screen plate on the PET film, printing Ag, carbon paste, Ag/AgCl and an insulating ink layer by layer, and drying each layer in an oven for 20 min at 70 ℃ after printing is finished; obtaining SPCE after the last layer is dried, and connecting the SPCE with an electrochemical workstation for testing;

s2.3, mixing 1 ml of MXene solution with a proper amount of carbon paste, quickly stirring until clear liquid appears on the surface, and continuously stirring until no liquid is separated out to obtain saturated MXene/C mixed ink;

s2.4, printing the saturated MXene/C mixed ink on the working electrode area of the SPCE, and putting the working electrode area into a 70 ℃ oven to dry for 20 min to obtain the MXene/SPCE.

Further, the S3 concretely comprises the steps of adding 0.5wt% of CTS into 0.5M copper acetate solution, mixing, and then carrying out 2000S constant potential deposition at-0.4V potential to obtain MXene/CTS/Cu ₂ O/SPCE electrodes.

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

1. the invention utilizes transition metal carbide MXene and transition metal oxide Cu ₂ O and the like construct an enzyme-like catalyst with excellent catalytic activity, an electrochemical biosensor is prepared based on a PET-based screen printing electrode, and a high-sensitivity biosensor with good biocompatibility, large specific surface area and sufficient active sites is developed; the MXene two-dimensional nano material in the working electrode area has excellent biocompatibility and conductivity, large specific surface area and modified Cu ₂ And further enhancing the reactive sites on the surface of the electrode, and fully utilizing the synergistic effect of the active sites to realize the simultaneous detection of multiple substances through potential separation without mutual interference.

2. MXene/CTS/Cu of the invention ₂ The O/SPCE electrode can realize enzyme-free simultaneous detection of glucose and cholesterol, realizes high-sensitivity biomass detection by using an electrochemical measurement technology, improves the problems of high lower limit of enzyme electrode detection, low sensitivity, easy failure of working electrode, frequent replacement and the like, realizes accurate, quick and stable detection of a blood glucose/cholesterol sensor, and has the advantages of low cost, compact structure, simple operation, easy replacement and convenient carryingAnd (4) point, POCT can be realized only by a trace amount of samples.

3. Modification of Cu by electrochemical deposition ₂ O in Cu (CH) ₃ COO) ₂ CTS (0.5 wt%) is added into the solution to serve as an electrolyte solution, and the stability of the electrode test is enhanced by utilizing the electrostatic interaction between the CTS and MXene and the hydrogen bond interaction between amino groups on the CTS and OH, O and F groups on the surface of the MXene nanosheet.

4. The screen printing electrode has the advantages of simple manufacturing process, small size, good flexibility, low manufacturing cost and mass production, and is favorable for integrated development with portable wearable equipment.

Drawings

FIG. 1 is a schematic flow chart of the electrode preparation method for simultaneous detection of glucose and cholesterol in the present invention;

FIG. 2 is a scanning electron microscope image of the working area of the electrode in accordance with the present invention; wherein, FIG. 2a is before test, and FIG. 2b is after test;

FIG. 3 shows MXene/CTS/Cu electrodes of the present invention ₂ O/SPCE and MXene/Cu ₂ Comparing Cyclic Voltammetry (CV) curves of O/SPCE in a 1.0M NaOH solution;

FIG. 4 shows MXene/CTS/Cu in the present invention ₂ CV images of O/SPCE electrodes in NaOH solution; wherein

FIG. 4a is a CV image of an electrode in a 1.0M NaOH solution;

FIG. 4b is a CV curve of the electrode after the addition of different concentrations of glucose and cholesterol;

FIG. 5 shows MXene/CTS/Cu in the present invention ₂ The O/SPCE electrode is used for performing i-t image and linear fitting on cholesterol with different concentrations in a 1M NaOH electrolyte under the condition of adding 0.01 mM cholesterol every second;

FIG. 6 shows MXene/CTS/Cu in the present invention ₂ The O/SPCE electrode is used for performing i-t image and linear fitting on glucose with different concentrations in 1M NaOH electrolyte under the condition that 0.1 mM glucose is added every second;

FIG. 7 shows MXene/CTS/Cu in the present invention ₂ The O/SPCE electrode is used for selectively testing the detection of glucose and cholesterol in 1.0M NaOH electrolyte;

wherein, FIG. 7a is a comparison of current response values with 0.5 mM of other substances and 0.05 mM of cholesterol added at the cholesterol detection potential;

FIG. 7b is a comparison of current response values for the addition of 0.5 mM of other substances and 0.5 mM of glucose at the glucose detection potential.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be more clearly and completely described below with reference to the accompanying drawings in the examples of the present invention.

A method for detecting glucose and cholesterol simultaneously comprises the steps of oxidizing glucose at a positive potential by using Ti4+ in MXene, oxidizing cholesterol by using Cu2+ generated by Cu2O at a negative potential, outputting generated reaction current to a sensing detection end through the synergy of MXene and Cu2O, and outputting concentration information in real time by establishing a correlation model of blood glucose/cholesterol concentration and an electrical signal to realize enzyme-free simultaneous detection of glucose and cholesterol.

The invention discloses an electrode for simultaneously detecting and detecting glucose and cholesterol, which is MXene/CTS/Cu ₂ The O/SPCE electrode comprises an insulating layer 41, a PET substrate 45, an Ag/AgCl reference electrode 42, a C counter electrode 43 and MXene/CTS/Cu integrated on the PET substrate 45 ₂ An O/C working electrode 44.

The invention also discloses an electrode manufacturing method for detecting and detecting glucose and cholesterol, which comprises the steps of preparing MXene solution, mixing the MXene solution with carbon slurry, and modifying a working electrode area defined by SPCE through screen printing to obtain MXene/SPCE; subsequent electrodeposition of cuprous oxide Cu on MXene/SPCE ₂ Performing O treatment to obtain MXene/CTS/Cu ₂ O/SPCE electrodes.

In particular, the method comprises the following steps,

s1: etching an Al layer in MAX by using a hydrothermal method to generate a layered two-dimensional nano material to prepare an MXene solution;

s1.1 adding 1 g of lithium fluoride to 20 mL of 9M aqueous hydrochloric acid solution, then slowly adding 1 g of Ti over 10min ₃ AlC ₂ Will subsequently mixTransferring the compound into 35 ℃ water bath for treatment for 24 h, centrifuging at 3500 rpm for 10min, and pouring off the supernatant;

s1.2, washing the mixture precipitate after the supernatant is removed with deionized water, putting the mixture precipitate into a high-power ultrasonic machine for 750W ultrasonic for 10min, taking out the mixture precipitate, continuously centrifuging the mixture precipitate, and repeating the steps for many times until the pH value of the supernatant poured out after centrifugation reaches 5;

s1.3, adding ethanol serving as an intercalation agent into the centrifugal tube, and respectively carrying out ultrasonic treatment and centrifugation on the dispersion for 1 hour, wherein the ultrasonic power is 750W, and the centrifugation parameter is 10000 rpm;

s1.4, adding deionized water into the centrifugal precipitation product, continuing to perform ultrasonic treatment for 20 min at 750W power, then centrifuging the dispersion liquid for 3 min at 3500 rpm, and collecting the black brown supernatant as MXene solution.

S1.5, repeating S1.4 for multiple times to obtain more MXene solutions;

s2: mixing MXene solution with carbon slurry, modifying a working electrode area defined on the SPCE through screen printing, and drying to obtain an MXene/SPCE electrode;

s2.1, cutting a PET film into a proper size, cleaning the PET film with ethanol and deionized water, and drying the PET film; then, the membrane is placed in a working area of a screen printing machine, and a vacuum pump is started to enable the membrane to be tightly attached to the surface of the machine and ensure that no air bubbles exist;

s2.2, fully aligning the screen plate on the PET film, printing Ag, carbon paste, Ag/AgCl and an insulating ink layer by layer, and drying each layer in an oven for 20 min at 70 ℃ after printing is finished; obtaining SPCE after the last layer is dried, and connecting the SPCE with an electrochemical workstation for testing;

s2.3, mixing 1 ml of MXene solution with a proper amount of carbon paste, quickly stirring to obtain a clear liquid on the surface, and continuously stirring until no liquid is separated out to obtain saturated MXene/C mixed ink;

s2.4, printing the saturated MXene/C mixed ink on the working electrode area of the SPCE, and drying in an oven at 70 ℃ for 20 min to obtain the MXene/SPCE.

S3: under constant potential, electrodepositing cuprous oxide Cu on MXene/SPCE electrode ₂ Performing O treatment to obtain MXene/CTS/Cu ₂ O/SPCE electrode, specifically, 0.5wAdding t% CTS into 0.5M copper acetate solution, mixing, and performing constant potential deposition for 2000s at-0.4V potential to obtain MXene/CTS/Cu ₂ And (3) an O/SPCE electrode.

As shown in fig. 1, a preparation method and a structure of a screen printing electrode for simultaneously detecting glucose and cholesterol based on transition metal two-dimensional nanomaterial MXene are shown.

As shown in step 1 in fig. 1, MXene is prepared by etching with a fluoride-containing salt/hydrochloric acid mixed system.

Firstly, a fluoride-containing acid salt/hydrochloric acid mixed system is used for replacing hydrofluoric acid (HF), an Al layer in a MAX phase is etched by generating HF molecules, and the ethanol is used for further intercalation.

The method specifically comprises the following steps: 1 g of lithium fluoride (LiF) was added to 20 mL of 9M aqueous hydrochloric acid solution, and 1 g of Ti was slowly added over 10min ₃ AlC ₂ (MAX), the mixture was then transferred to a 35 ℃ water bath for 24 h, then centrifuged at 3500 rpm for 10min and the supernatant (strong acid product) was decanted. Washing the precipitate with deionized water, placing into a high-power ultrasonic machine, ultrasonic treating for 10min, taking out, centrifuging,

this procedure was repeated several times until the supernatant poured out after centrifugation reached pH 5.

And then, adding ethanol as an intercalating agent into the centrifuge tube, and respectively carrying out ultrasonic treatment and centrifugation on the dispersion for 1 hour, wherein the ultrasonic power is 750W, and the centrifugation parameter is 10000 rpm.

And adding deionized water into the centrifugal precipitation product, continuing to perform ultrasonic treatment for 20 min at the power of 750W, then centrifuging the dispersion liquid for 3 min at 3500 rpm, and collecting the black brown supernatant as an MXene solution.

Repeating the above steps for multiple times to obtain more less-layer dispersion liquid.

Screen Printed Carbon Electrodes (SPCE) and MXene/SPCE as shown in fig. 1, step 2;

mixing 1 mL of the MXene solution with a proper amount of carbon paste, and quickly stirring to obtain clear liquid on the surface, wherein the clear liquid on the surface is poured off because the binding force of MXene molecules and the carbon paste is greater than the binding force of MXene molecules and water;

and continuously stirring until no liquid is precipitated to obtain the saturated MXene/C mixed ink.

And printing the mixed slurry in a working electrode area, and drying in a 70 ℃ drying oven for 20 min to obtain MXene/SPCE.

As shown in step 2 of FIG. 1, Cu is electrodeposited at constant potential ₂ O to obtain MXene/CTS/Cu ₂ O/SPCE；

Modification of Cu by electrochemical deposition ₂ O, but the stability of the combination with the electrode is poor, and the corresponding signal of the current is unstable, so that the Cu (CH) is ₃ COO) ₂ CTS (0.5 wt%) is added into the solution to serve as an electrolyte solution, and the stability of the electrode test is enhanced by utilizing the electrostatic interaction between the CTS and MXene and the hydrogen bond interaction between amino groups on the CTS and OH, O and F groups on the surface of the MXene nanosheet.

Carrying out 2000s of electrodeposition on MXene/SPCE under-0.4V potential by using a time-current method (i-t) method to obtain MXene/CTS/Cu ₂ O/SPCE。

FIG. 2 is a microstructure of a working region of a prepared electrode, and SEM images show that Cu is obviously present before the test ₂ O particles are fully attached to the surface of the electrode, and after multiple tests, Cu ₂ O is consumed by oxidation of cholesterol leaving only a small amount of particles on the surface.

Description of Cu ₂ O oxidizes cholesterol at negative potential, thus utilizing Cu ₂ O can detect cholesterol.

FIG. 3 shows MXene/CTS/Cu test by CV method ₂ The O/SPCE electrode is conductive. As the Ti element in MXene is easily oxidized into titanium dioxide (TiO) at a larger positive potential ₂ ) Forming compact oxide film to block ion transmission and influence electrode sensing performance, setting voltage range to-0.8V to 0.4V, standing time to be 2 s, scanning speed to be 50 mV/s, using 1.0M sodium hydroxide (NaOH) solution as electrolyte to obtain CV curve, and obtaining MXene/Cu after electrochemical deposition ₂ O/SPCE and MXene/CTS/Cu ₂ The significant increase in current values for O/SPCE compared to MXene/SPCE is probably due to the modified Cu ₂ After O, active sites are increased, electron transport channels are improved, and electrode conductivity is enhanced.

Although MXene/Cu ₂ The O/SPCE conductivity is the best, but the CV curve only shows a pair of oxidation-reduction peaks of Cu, which indicates that the Cu ₂ The molecular bonding force between O and MXene is insufficient.

And in Cu (CH) ₃ COO) ₂ After adding CTS to the solution, although the current peak value is equal to MXene/Cu ₂ The O/SPCE ratio is reduced, but MXene/CTS/Cu ₂ The O/SPCE has a few obvious pairs of redox peaks and is stable in the electrochemical test process, so that the detection of cholesterol and glucose is hopeful.

FIG. 4 is a CV test image of the electrode in a 1.0M NaOH solution, wherein in FIG. 4a, peak I is Cu ¹⁺ To Cu, peak II is Cu to Cu ¹⁺ Peak III is Cu ²⁺ To Cu ¹⁺ Peak IV Cu ¹⁺ To Cu ²⁺ Peak V is Ti ⁴⁺ To Ti ²⁺ Peak VI is Ti at 0.35V potential ^{2 +} To Ti ⁴⁺ 。

Glucose is oxidized by Ti element in MXene at positive potential, cholesterol is oxidized by Cu element at negative potential, and the synergistic effect of the two components is exerted to realize multifunctional detection.

In FIG. 4b, MXene/CTS/Cu was evaluated ₂ The detection capability of the O/SPCE to cholesterol and glucose is realized by adding two substances to be detected respectively, and the glucose only causes positive potential current response.

The addition of cholesterol caused only a change in peak current at peak i and peak iii. The peak I current is smaller, so that the peak III-0.165V is selected as the cholesterol test potential, and the peak VI, which is 0.35V, is selected as the glucose test potential.

FIGS. 5 and 6 show the results of it tests performed at peak III and peak VI potentials, respectively, again using 1.0M NaOH as the electrolyte.

Firstly, cholesterol is detected on a peak III, because the water solubility of the cholesterol is poor, the cholesterol is dissolved in ethanol to prepare a 10 mM high-concentration cholesterol solution, 60 mu l of the solution is dripped into 60 ml of electrolyte each time, namely, the concentration of the cholesterol is increased by 0.01 mM each time, and a test image and an error bar after multiple tests are shown in figure 5.

Sensor pair cholesterolThe fitted line detected was I (mA) = -0.00609C (mM) + 0.08 (R) ² = 0.9951), the cholesterol detection sensitivity is 48.44 muA.mM ^-1 cm ^-2 The linear range was 15.5-100 μ M, and the lower limit of detection was calculated (S/N = 3) to be 15.5 μ M.

The it curve for glucose measurement at peak VI, i.e., 0.35V potential, is shown in FIG. 6, and error bars are made and fitted linearly for multiple measurements, I (mA) = 0.171C (mM) -0.007 (R) ² = 0.9944) its sensitivity to glucose is 1361.36 μ a.mm ^-1 cm ^-2 . The linear range was 78.9-1000. mu.M, with a lower detection limit of (S/N = 3) 78.9. mu.M.

Demonstration of MXene/CTS/Cu ₂ O/SPCE has the ability to detect small molecules commonly found in both glucose and cholesterol organisms.

Fig. 7 is an anti-interference test of the electrodes to further demonstrate the potential of the sensor application.

The sensor is proved to have excellent anti-interference characteristics by respectively adding 5 mM concentration of Uric Acid (UA), Ascorbic Acid (AA), acetaminophen (APAP), sodium chloride (NaCl) and lactose (L-T) into NaOH solution to serve as common interference substances in blood and comparing the common interference substances with current signals caused by 0.1 mM glucose and 0.05 mM cholesterol respectively, and can be used as a multifunctional biosensor for practical test.

TABLE 1 MXene/CTS/Cu ₂ O/SPCE electrode simultaneously detects glucose and cholesterol in 2% blood samples

Sample(s)	Test object	Amount of the substance to be measured	Test value of the object to be tested	Recovery (%)
					1	Glucose	0.1mM	0.09399496	93.99%
	Cholesterol	0.02mM	0.02102842	105.14%
					2	Glucose	0.1mM	0.09364423	93.64%
	Cholesterol	0.02mM	0.01922129	96.11%
					3	Glucose	0.1mM	0.09493023	94.93%
	Cholesterol	0.02mM	0.02052407	102.62%
					4	Glucose	0.1mM	0.1056274	105.63%
	Cholesterol	0.02mM	0.01936915	96.85%

Table 1 shows the results of actual blood sample testing of the electrodes for MXene/CTS/Cu ₂ O/SPCE performed the actual blood sample test, which was provided by the large Hospital in Nanjing.

Glucose is normally present in humans at around 4 mM, while cholesterol is desirably present at <5.2 mM, with free cholesterol in about 10% being available for direct oxidation by nanomaterials. Therefore, after the normal blood sample is diluted by 50 times, the contents of glucose and cholesterol just fall in the detection range of the material prepared in the text, and the blood sample with high biomass content can be diluted for multiple times, so that the blood volume for detection is greatly reduced.

2 mL of serum is diluted by 50 times with 1.0M NaOH electrolyte to be used as a test solution, the glucose and cholesterol molecule detection capability is respectively tested by using a standard recovery method, the results are shown in Table 5-1, the recovery rates are 93% -106%, the error is not more than 10%, and the electrode provided by the invention can realize accurate and rapid detection of multiple substances.

The foregoing detailed description is provided for the purpose of illustrating the technical concept and structural features of the present invention and is not intended to limit the scope of the present invention, which is defined by the claims and their equivalents.

Claims (8)

1. A method for simultaneously detecting and detecting glucose and cholesterol is characterized in that: glucose is oxidized at a positive potential by using Ti4+ in MXene, cholesterol is oxidized by using Cu2+ generated by Cu2O at a negative potential, and the MXene and the Cu2O act synergistically to realize enzyme-free simultaneous detection of glucose and cholesterol.

2. The method for simultaneously detecting glucose and cholesterol according to claim 1, wherein: through the synergistic effect of the MXene and the Cu2O, the generated reaction current is output to a sensing detection end through a microelectrode, and concentration information is output in real time through establishing a correlation model of the blood glucose/cholesterol concentration and an electrical signal.

3. An electrode for simultaneously detecting glucose and cholesterol, comprising: the electrode is MXene/CTS/Cu ₂ An O/SPCE electrode comprising an insulating layer (41), a PET substrate (45) and an Ag/AgCl reference electrode (42), a C counter electrode (43) and MXene/CTS/Cu integrated on the PET substrate (45) ₂ An O/C working electrode (44).

4. A method for manufacturing an electrode for detecting and detecting glucose and cholesterol is characterized in that: preparing MXene solution, mixing the MXene solution with carbon slurry, and modifying a working electrode area defined by SPCE through screen printing to obtain MXene/SPCE; subsequent electrodeposition of cuprous oxide Cu on the MXene/SPCE ₂ Performing O treatment to obtain MXene/CTS/Cu ₂ And (3) an O/SPCE electrode.

5. The method for manufacturing an electrode for detecting glucose and cholesterol according to claim 4, wherein: comprises the following steps of (a) carrying out,

s1: etching an Al layer in MAX by using a hydrothermal method to generate a layered two-dimensional nano material to prepare an MXene solution;

s2: mixing the MXene solution with carbon slurry, modifying a working electrode area defined on the SPCE through screen printing, and drying to obtain an MXene/SPCE electrode;

s3: under constant potential, the MXene/SPCE electrode is subjected to electrodeposition of cuprous oxide Cu ₂ Performing O treatment to obtain MXene/CTS/Cu ₂ And (3) an O/SPCE electrode.

6. The method of claim 5, wherein: the step S1 specifically includes the following steps,

s1.1, 1 g of lithium fluoride is added to 20 mL of 9M aqueous hydrochloric acid solution, and then 1 g of Ti is slowly added within 10min ₃ AlC ₂ Then transferring the mixture into a 35 ℃ water bath for treatment for 24 h, centrifuging at 3500 rpm for 10min, and pouring off the supernatant;

s1.2, washing the mixture precipitate after the supernatant is removed with deionized water, putting the mixture precipitate into a high-power ultrasonic machine (750W) for ultrasonic treatment for 10min, taking out the mixture precipitate and continuing to centrifuge, and repeating the step for multiple times until the pH value of the supernatant poured out after centrifugation reaches 5;

s1.3, adding ethanol as an intercalation agent into the centrifuge tube, respectively carrying out ultrasonic treatment and centrifugation on the dispersion for 1 hour, wherein the ultrasonic power is 750W, and the centrifugation parameter is 10000 rpm;

s1.4, adding deionized water into the centrifugal precipitation product, continuing to perform ultrasonic treatment for 20 min at 750W power, then centrifuging the dispersion liquid for 3 min at 3500 rpm, and collecting the black brown supernatant as MXene solution.

7. The electrode production method according to claim 5 or 6, characterized in that: the S2 specifically includes the following steps,

s2.1, cutting the PET film into a proper size, cleaning with ethanol and deionized water, and drying; then placing the membrane in a working area of a screen printing machine, and opening a vacuum pump to enable the membrane to cling to the surface of the machine and ensure that no air bubbles exist;

s2.2, fully aligning the screen plate on the PET film, printing Ag, carbon paste, Ag/AgCl and an insulating ink layer by layer, and drying each layer in an oven for 20 min at 70 ℃ after printing is finished; obtaining SPCE after the last layer is dried, and connecting the SPCE with an electrochemical workstation for testing;

s2.3, mixing 1 ml of MXene solution with a proper amount of carbon slurry, quickly stirring until clear liquid appears on the surface, and continuously stirring until no liquid is separated out to obtain saturated MXene/C mixed ink;

s2.4, printing the saturated MXene/C mixed ink on the working electrode area of the SPCE, and putting the working electrode area into a 70 ℃ oven to dry for 20 min to obtain the MXene/SPCE.

8. The method of claim 7, wherein: s3 specifically comprises adding 0.5wt% of CTS into 0.5M copper acetate solution, mixing, and performing constant potential deposition for 2000S at-0.4V potential to obtain MXene/CTS/Cu ₂ And (3) an O/SPCE electrode.

Images