CN113176314A - Based on g-C3N4/Mo:BiVO4And CuS device preparation - Google Patents

Abstract

The invention discloses a method based on g-C₃N₄/Mo:BiVO₄Firstly, g-C with good photoelectrochemical signals is synthesized by combining with a preparation method of a CuS catalytic signal amplification sensor₃N₄/Mo:BiVO₄BiVO is increased due to Mo doping₄The carrier concentration improves the carrier separation efficiency; at the same time, g-C₃N₄BiVO loaded to Mo₄Forming a heterojunction to make the photogenerated holes from BiVO₄The generated and smoothly transmitted to g-C3N4, accelerates the separation of electrons and holes, and effectively inhibits the recombination of carriers; in addition, the CuS-GR is modified on the secondary antibody to be used as a signal amplification carrier, so that on one hand, the impedance of the sensor is increased, the photoelectric signal is reduced, on the other hand, the CuS is used as a p-type semiconductor, the light energy can be competitively absorbed, the electron donating reagent ascorbic acid in the solution can be competitively consumed, the signal is reduced, and the satisfactory detection line is finally detected by the sandwich type sensor.

Description

Based on g-C3N4/Mo:BiVO4And CuS device preparation

Technical Field

The invention relates to the field of quantitative detection of carcinoembryonic antigen, in particular to a method based on g-C₃N₄/Mo:BiVO₄A preparation method of a sensor combining CuS catalytic signal amplification.

Background

In recent years, the number of tumor cancer patients has increased, and among all cancers, gastric cancer is very common and is the 1 cancer with the highest incidence. The gastric cancer is usually mistaken for gastritis and the like, patients do not pay attention to the hidden improvement of diseases caused by detection and treatment, and the patients find that the optimal treatment opportunity is missed and the possibility of removing tumors by surgery is lower and the success rate of treatment is lower. Early accurate diagnosis is therefore of concern. Gastroscopy is the main method for diagnosing stomach diseases, but the operation is invasive and requires preoperative bowel preparation treatment, and the clinical application is greatly limited. The gastric cancer tumor marker can reflect physicochemical properties of the existence of tumors, and is convenient and sensitive to detect, so that the application is gradually increased in recent years.

The photoelectrochemical biosensor is a new biomarker detection technology, and has the advantages of simple operation, high response speed, miniaturization and the like, so that the photoelectrochemical biosensor is widely concerned by countries in the world. Furthermore, due to the separation of the input (light) and output (electrical) signals, the photoelectrochemical biosensor has a low background signal and excellent sensitivity. In recent years, due to the need for rapid, ultra-sensitive bioassays and the trend towards miniaturization of analytical methods, unique signal amplification techniques have long been appreciated in the field.

Disclosure of Invention

The invention aims to construct a sandwich type signal amplification electrochemical biosensor for detecting carcinoembryonic antigen.

In order to solve the technical problem, the invention is realized by the following measures: a preparation method of a g-C3N 4/Mo-based BiVO4 combined CuS catalytic signal amplification sensor is characterized by comprising the following steps:

(1) electrodeposition of the BiOI electrode: weighing 0.4 mol/L KI (99%) in a clean beaker, dissolving in 50 mL of distilled water, magnetically stirring, and slowly dropwise adding concentrated HNO into the solution after the KI is fully dissolved₃Adjusting pH to about 1.7, continuously stirring, adding 0.04 mol/L Bi (NO)₃)₃·5H₂O (99.0%), stirring until dissolved; weighing 0.23 mol/L p-benzoquinone in another clean beaker, dissolving in 20 mL absolute ethyl alcohol, and stirring for dissolving; finally, uniformly mixing the two cups of solution to obtain electroplating solution; electrodeposition usingA three-port quartz electrolytic tank, and three electrode systems are respectively doped with F-SnO₂The reference electrode of the Ag/AgCl electrode and the Pt electrode are counter electrodes, and the BiOI electrode is obtained by electrodeposition for 200 s under the cathode voltage of-0.1V and the Ag/AgCl;

（2）Mo:BiVO₄preparing an electrode: dissolving 0.2 mol/L of vanadium acetylacetonate containing 1% of molybdenum acetylacetonate in 0.2 mL of dimethyl sulfoxide, stirring and dissolving, dripping the solution on the surface of a BiOI electrode, and then putting the BiOI electrode into a muffle furnace to anneal for 2 hours at 450 ℃ to convert the BiOI into Mo, namely BiVO₄(ii) a In this process, a black V is formed due to the excess of vanadium acetoneacetate₂O₅The sample was immersed in 1mol/L NaOH solution and stirred to remove excess V₂O₅(ii) a Finally washing with deionized water and drying at room temperature to obtain Mo-doped BiVO₄An electrode;

（3）g-C₃N₄preparation of the dispersion: weighing 5 g of melamine powder in an alumina crucible, heating to 500 ℃ at a heating rate of 2 ℃/min in a muffle furnace, and calcining for 4 h to obtain g-C₃N₄Yellow block, grinding thoroughly, collecting 100 mg g-C₃N₄Adding 100 mL of isopropanol into the powder, fully stirring, performing ultrasonic treatment for 24 hours to obtain uniformly dispersed suspension, performing centrifugal separation on the stripped suspension for 10 min, and drying after centrifugation;

（4）g-C₃N₄/Mo:BiVO₄the preparation of (1): BiVO is the prepared Mo₄Electrodes in g-C₃N₄Soaking in isopropanol solution for 1 h, and annealing at 450 deg.C for 1 h to obtain g-C with different soaking times₃N₄/Mo:BiVO₄An electrode;

(5) synthesis of Au @ CuS-GR: 40 mg of CuAc were added under stirring₂ H₂O and 7.5 mL of a 1 mg/mL GO solution were added to 20 mL of ultrapure water, 25 mL of 0.67 mg/mL NaOH was slowly added dropwise to the above solution with constant stirring for 10 min, after centrifugation and washing with ultrapure water, the precipitate was dispersed in 30 mL of an 8 mmol thioacetamide solution, the mixture was then heated at 160 ℃ for 6.5 h, the resulting product was isolated by centrifugation and washed with EtOHWashing alcohol and ultrapure water, followed by drying at 35 ℃ for 12 h to obtain CuS-graphene oxide (CuS-GR), then, dispersing 1.25 mg of CuS-GR in 10 mL of ultrapure water and performing sonication for 5 min, 100. mu.L of 10 mg/mL HAuCl₄And 300. mu.L of an ammonium aqueous solution were gradually added to the above solution in this order, and after stirring for 30 min, 0.8 mL of 10 mmol of AA was added dropwise to reduce HAuCl₄After stirring for 4.5 h, the final product obtained is centrifuged and washed with ultrapure water and ethanol; finally, Au @ CuS-GR was dispersed in 10 mL of ultrapure water for further use;

(6) synthesis of Ab₂-Au @ CuS-GR: 1 mL of a secondary antibody, Ab, at a concentration of 10. mu.g/mL₂Adding into the synthesized product of step (5), incubating at 4 deg.C for 2 h, washing 3 times with pH 7.4 phosphate buffer solution to remove non-complexed Ab₂To obtain Ab₂-Au@CuS-GR；

(7) Construction of the photoelectrochemical sensor: the conductive glass is Indium Tin Oxide (ITO) glass, the conductive glass is cut into strips of 4.0 multiplied by 0.5 cm, ultrasonic cleaning is carried out for 5 min by using acetone solution, secondary distilled water and absolute ethyl alcohol in sequence, and then drying is carried out under nitrogen for standby; 20 μ L of g-C prepared above₃N₄/Mo:BiVO₄The solution was coated on the surface of an ITO electrode, dried at room temperature, and then 6 μ L of a primary antibody, Ab1, with a concentration of 10 μ g/mL was incubated at 4 ℃ for 16 h, thoroughly washed 3 times with a phosphate buffer solution of pH 7.4; continuously dripping 20 mu L of 3% bovine serum albumin to block the non-specific binding sites, thoroughly washing the non-specific binding sites for 3 times by using a phosphate buffer solution with pH 7.4, dripping 20 mu L of prostate antigens with different concentrations onto the surface of the electrode, incubating for 30 min at room temperature, and washing for 3 times by using a phosphate buffer solution with pH 7.4; continuously dropwise adding 20 mu L of Ab synthesized in the step (6)₂-Au @ CuS-GR, incubated at room temperature for 2 h;

(8) photoelectrochemical detection of sandwich-type signal amplification biosensors: and (3) taking the modified electrode processed in the step (7) as a working electrode, taking the counter electrode as a platinum wire electrode, taking the reference electrode as an Ag/AgCl electrode, taking the bias voltage value as 0V, taking a xenon lamp as a light source for stimulation, taking an electrolytic cell as a phosphate buffer solution system (containing 1mol/L of ascorbic acid) with the pH value of 7.4, and measuring a current I-T curve to detect the photoelectric property.

The invention has the beneficial effects that:

(1) the method has the advantages of low cost, simple experimental operation and easy control of reaction conditions.

(2) BiVO is increased due to Mo doping₄The carrier concentration improves the carrier separation efficiency; at the same time, g-C₃N₄BiVO loaded to Mo₄Forming a heterojunction to make the photogenerated holes from BiVO₄Generated and smoothly transmitted to g-C3N4, accelerates the separation of electrons and holes, and effectively inhibits the recombination of carriers.

(3) The large specific surface area of GR can enable more CuS and gold nano-ions to be loaded on the surface.

(4) The higher quenching efficiency of the CuS as a typical p-type semiconductor loaded on the GR as a signal tag can be obtained, and in addition, in order to combine the CuS-GR with the antigen, gold nano-ions are marked on the GR, and the gold nano-particles are combined with the antigen through the non-covalent bonding between Au and thiol.

Detailed Description

In order to further understand the invention, the technical scheme is implemented by combining the embodiment, and the specific implementation mode is given:

(1) electrodeposition of the BiOI electrode: weighing 0.4 mol/L KI (99%) in a clean beaker, dissolving in 50 mL of distilled water, magnetically stirring, and slowly dropwise adding concentrated HNO into the solution after the KI is fully dissolved₃Adjusting pH to about 1.7, continuously stirring, adding 0.04 mol/L Bi (NO)₃)₃·5H₂O (99.0%), stirring until dissolved; weighing 0.23 mol/L p-benzoquinone in another clean beaker, dissolving in 20 mL absolute ethyl alcohol, and stirring for dissolving; finally, uniformly mixing the two cups of solution to obtain electroplating solution; the electrodeposition adopts a three-port quartz electrolytic tank, and three electrode systems are respectively doped with F-SnO₂The reference electrode of the Ag/AgCl electrode and the Pt electrode are counter electrodes, and the BiOI electrode is obtained by electrodeposition for 200 s under the cathode voltage of-0.1V and the Ag/AgCl;

（2）Mo:BiVO₄preparing an electrode: 0.2 mol/L of vanadium acetylacetonate containing 1% of molybdenum acetylacetonate was dissolved in 0.2 mL of dimethyl sulfoxideIn sulfone, stirring and dissolving, dripping the solution on the surface of a BiOI electrode, and then putting the BiOI electrode into a muffle furnace to anneal for 2 hours at 450 ℃ to convert the BiOI into Mo, namely BiVO₄(ii) a In this process, a black V is formed due to the excess of vanadium acetoneacetate₂O₅The sample was immersed in 1mol/L NaOH solution and stirred to remove excess V₂O₅(ii) a Finally washing with deionized water and drying at room temperature to obtain Mo-doped BiVO₄An electrode;

（3）g-C₃N₄preparation of the dispersion: weighing 5 g of melamine powder in an alumina crucible, heating to 500 ℃ at a heating rate of 2 ℃/min in a muffle furnace, and calcining for 4 h to obtain g-C₃N₄Yellow block, grinding thoroughly, collecting 100 mg g-C₃N₄Adding 100 mL of isopropanol into the powder, fully stirring, performing ultrasonic treatment for 24 hours to obtain uniformly dispersed suspension, performing centrifugal separation on the stripped suspension for 10 min, and drying after centrifugation;

（4）g-C₃N₄/Mo:BiVO₄the preparation of (1): BiVO is the prepared Mo₄Electrodes in g-C₃N₄Soaking in isopropanol solution for 1 h, and annealing at 450 deg.C for 1 h to obtain g-C with different soaking times₃N₄/Mo:BiVO₄An electrode;

(5) synthesis of Au @ CuS-GR: 40 mg of CuAc were added under stirring₂ H₂O and 7.5 mL of a 1 mg/mL GO solution were added to 20 mL of ultrapure water, 25 mL of 0.67 mg/mL NaOH was slowly added dropwise to the above solution with constant stirring for 10 min, after centrifugation and washing with ultrapure water, the precipitate was dispersed in 30 mL of an 8 mmol thioacetamide solution, and then the mixture was heated at 160 ℃ for 6.5 h, the resulting product was separated by centrifugation and washed with ethanol and ultrapure water, and then dried at 35 ℃ for 12 h to obtain CuS-graphene oxide (CuS-GR), then 1.25 mg of CuS-GR was dispersed in 10 mL of ultrapure water and subjected to sonication for 5 min, and 100. mu.L of 10 mg/mL HAuCl was added₄And 300. mu.L of an ammonium aqueous solution were gradually added to the above solution in this order, and after stirring for 30 min, 0.8 mL of 10 mmol of AA was added dropwise to reduce HAuCl₄After stirring for 4.5 hCentrifuging the final product, and washing with ultrapure water and ethanol; finally, Au @ CuS-GR was dispersed in 10 mL of ultrapure water for further use;

(6) synthesis of Ab₂-Au @ CuS-GR: 1 mL of a secondary antibody, Ab, at a concentration of 10. mu.g/mL₂Adding into the synthesized product of step (5), incubating at 4 deg.C for 2 h, washing 3 times with pH 7.4 phosphate buffer solution to remove non-complexed Ab₂To obtain Ab₂-Au@CuS-GR；

(7) Construction of the photoelectrochemical sensor: the conductive glass is Indium Tin Oxide (ITO) glass, the conductive glass is cut into strips of 4.0 multiplied by 0.5 cm, ultrasonic cleaning is carried out for 5 min by using acetone solution, secondary distilled water and absolute ethyl alcohol in sequence, and then drying is carried out under nitrogen for standby; 20 μ L of g-C prepared above₃N₄/Mo:BiVO₄The solution was coated on the surface of an ITO electrode, dried at room temperature, and then 6 μ L of a primary antibody, Ab1, with a concentration of 10 μ g/mL was incubated at 4 ℃ for 16 h, thoroughly washed 3 times with a phosphate buffer solution of pH 7.4; continuously dripping 20 mu L of 3% bovine serum albumin to block the non-specific binding sites, thoroughly washing the non-specific binding sites for 3 times by using a phosphate buffer solution with pH 7.4, dripping 20 mu L of prostate antigens with different concentrations onto the surface of the electrode, incubating for 30 min at room temperature, and washing for 3 times by using a phosphate buffer solution with pH 7.4; continuously dropwise adding 20 mu L of Ab synthesized in the step (6)₂-Au @ CuS-GR, incubated at room temperature for 2 h;

(8) photoelectrochemical detection of sandwich-type signal amplification biosensors: the modified electrode treated in the step (7) is used as a working electrode, the counter electrode is a platinum wire electrode, the reference electrode is an Ag/AgCl electrode, the bias voltage value is 0V, a xenon lamp is used as a light source for stimulation, the electrolytic cell is a phosphate buffer solution system (containing 1mol/L of ascorbic acid) with the pH of 7.4, the photoelectric property is detected by measuring a current I-T curve, the linear equation is I = -2.5 log (c) -35.14, the correlation coefficient is 0.993, the detection limit is 0.03 pg/mL, and the prostate specific antigen is detected with high sensitivity.

Claims (1)

1. Based on g-C₃N₄/Mo:BiVO₄Preparation method of sensor combining CuS catalytic signal amplification and characteristic bag thereofThe method comprises the following steps:

(1) electrodeposition of the BiOI electrode: weighing 0.4 mol/L KI (99%) in a clean beaker, dissolving in 50 mL of distilled water, magnetically stirring, and slowly dropwise adding concentrated HNO into the solution after the KI is fully dissolved₃Adjusting pH to about 1.7, continuously stirring, adding 0.04 mol/L Bi (NO)₃)₃·5H₂O (99.0%), stirring until dissolved; weighing 0.23 mol/L p-benzoquinone in another clean beaker, dissolving in 20 mL absolute ethyl alcohol, and stirring for dissolving; finally, uniformly mixing the two cups of solution to obtain electroplating solution; the electrodeposition adopts a three-port quartz electrolytic tank, and three electrode systems are respectively doped with F-SnO₂The reference electrode of the Ag/AgCl electrode and the Pt electrode are counter electrodes, and the BiOI electrode is obtained by electrodeposition for 200 s under the cathode voltage of-0.1V and the Ag/AgCl;

（2）Mo:BiVO₄preparing an electrode: dissolving 0.2 mol/L of vanadium acetylacetonate containing 1% of molybdenum acetylacetonate in 0.2 mL of dimethyl sulfoxide, stirring and dissolving, dripping the solution on the surface of a BiOI electrode, and then putting the BiOI electrode into a muffle furnace to anneal for 2 hours at 450 ℃ to convert the BiOI into Mo, namely BiVO₄(ii) a In this process, a black V is formed due to the excess of vanadium acetoneacetate₂O₅The sample was immersed in 1mol/L NaOH solution and stirred to remove excess V₂O₅(ii) a Finally washing with deionized water and drying at room temperature to obtain Mo-doped BiVO₄An electrode;

（3）g-C₃N₄preparation of the dispersion: weighing 5 g of melamine powder in an alumina crucible, heating to 500 ℃ at a heating rate of 2 ℃/min in a muffle furnace, and calcining for 4 h to obtain g-C₃N₄Yellow block, grinding thoroughly, collecting 100 mg g-C₃N₄Adding 100 mL of isopropanol into the powder, fully stirring, performing ultrasonic treatment for 24 hours to obtain uniformly dispersed suspension, performing centrifugal separation on the stripped suspension for 10 min, and drying after centrifugation;

（4）g-C₃N₄/Mo:BiVO₄the preparation of (1): BiVO is the prepared Mo₄Electrodes in g-C₃N₄Soaking in isopropanol solution for 1 h, and annealing at 450 deg.C for 1 h to obtain compact structureTo obtain g-C with different soaking times₃N₄/Mo:BiVO₄An electrode;

(5) synthesis of Au @ CuS-GR: 40 mg of CuAc were added under stirring₂ H₂O and 7.5 mL of a 1 mg/mL GO solution were added to 20 mL of ultrapure water, 25 mL of 0.67 mg/mL NaOH was slowly added dropwise to the above solution with constant stirring for 10 min, after centrifugation and washing with ultrapure water, the precipitate was dispersed in 30 mL of an 8 mmol thioacetamide solution, and then the mixture was heated at 160 ℃ for 6.5 h, the resulting product was separated by centrifugation and washed with ethanol and ultrapure water, and then dried at 35 ℃ for 12 h to obtain CuS-graphene oxide (CuS-GR), then 1.25 mg of CuS-GR was dispersed in 10 mL of ultrapure water and subjected to sonication for 5 min, and 100. mu.L of 10 mg/mL HAuCl was added₄And 300. mu.L of an ammonium aqueous solution were gradually added to the above solution in this order, and after stirring for 30 min, 0.8 mL of 10 mmol of AA was added dropwise to reduce HAuCl₄After stirring for 4.5 h, the final product obtained is centrifuged and washed with ultrapure water and ethanol; finally, Au @ CuS-GR was dispersed in 10 mL of ultrapure water for further use;

(6) synthesis of Ab₂-Au @ CuS-GR: 1 mL of a secondary antibody, Ab, at a concentration of 10. mu.g/mL₂Adding into the synthesized product of step (5), incubating at 4 deg.C for 2 h, washing 3 times with pH 7.4 phosphate buffer solution to remove non-complexed Ab₂To obtain Ab₂-Au@CuS-GR；

(7) Construction of the photoelectrochemical sensor: the conductive glass is Indium Tin Oxide (ITO) glass, the conductive glass is cut into strips of 4.0 multiplied by 0.5 cm, ultrasonic cleaning is carried out for 5 min by using acetone solution, secondary distilled water and absolute ethyl alcohol in sequence, and then drying is carried out under nitrogen for standby; 20 μ L of g-C prepared above₃N₄/Mo:BiVO₄The solution was coated on the surface of an ITO electrode, dried at room temperature, and then 6 μ L of a primary antibody, Ab1, with a concentration of 10 μ g/mL was incubated at 4 ℃ for 16 h, thoroughly washed 3 times with a phosphate buffer solution of pH 7.4; continuously dripping 20 mu L of 3% bovine serum albumin to block the nonspecific binding sites, thoroughly washing with phosphate buffer solution with pH of 7.4 for 3 times, dripping 20 mu L of prostate antigen with different concentrations to the surface of the electrode, and standing at room temperatureIncubating for 30 min, and washing 3 times with phosphate buffer solution with pH 7.4; continuously dropwise adding 20 mu L of Ab synthesized in the step (6)₂-Au @ CuS-GR, incubated at room temperature for 2 h;

(8) photoelectrochemical detection of sandwich-type signal amplification biosensors: and (3) taking the modified electrode processed in the step (7) as a working electrode, taking the counter electrode as a platinum wire electrode, taking the reference electrode as an Ag/AgCl electrode, taking the bias voltage value as 0V, taking a xenon lamp as a light source for stimulation, taking an electrolytic cell as a phosphate buffer solution system (containing 1mol/L of ascorbic acid) with the pH value of 7.4, and measuring a current I-T curve to detect the photoelectric property.