CN110320281B - Surface acoustic wave biosensor for depositing oxide nanoparticle/polyacrylamide composite sensitive film and preparation method thereof - Google Patents
Surface acoustic wave biosensor for depositing oxide nanoparticle/polyacrylamide composite sensitive film and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a surface acoustic wave biosensor for depositing an oxide nanoparticle/polyacrylamide composite sensitive film and a preparation method thereof, wherein the preparation method comprises the following steps: uniformly dispersing an AM monomer in a KCl aqueous solution to obtain an AM aqueous solution, adding oxide nanoparticles into the AM aqueous solution, uniformly dispersing, and adjusting the pH to 5.5-7.5 to obtain a suspension; immersing the interdigital and piezoelectric piece of the surface acoustic wave biosensor into the suspension, putting the bottom of a platinum wire into the suspension, electrically connecting the surface acoustic wave biosensor and the platinum wire with an electrochemical workstation respectively, and depositing an oxide nanoparticle/polyacrylamide composite sensitive film on the surface acoustic wave biosensor by adopting a cyclic voltammetry method.
Description
Technical Field
The invention belongs to the technical field of surface acoustic wave biosensors, and particularly relates to a surface acoustic wave biosensor deposited with an oxide nanoparticle/polyacrylamide composite sensitive film and a preparation method thereof.
Background
The surface acoustic wave biosensor (SAW sensor) mainly comprises a piezoelectric substrate, an interdigital transducer and a sensitive film. When the surface acoustic wave propagates along the solid surface, the interdigital transducer realizes the excitation and conversion of signals, and the sensitive film induces the change of physical and chemical quantities such as components, concentration, temperature and the like to cause the change of signals such as the frequency, the phase and the like of the SAW, so that the SAW device extracts the signals in propagation.
Although the SAW sensor has the advantages of high sensitivity, high accuracy, small volume, low power consumption and capability of realizing wireless sensing, the problems of small volume, process compatibility of in-situ synthesis and the like cause difficulty in preparation of the sensitive film, so that the selection range of the sensitive film is limited. At present, few types of sensitive films are used on SAW devices, wherein metal oxides and metal sensitive layers are main sensitive materials and are mostly prepared by methods such as sputtering, evaporation and the like, a biological sensitive layer is formed by relying on various noble metal transition regions such as a gold coating and the like, various nano materials and the like are prepared by methods such as drop coating and drying, and the problem of low adhesive force exists, and the biological sensitive layer is difficult to be polymerized with an electrode of the SAW. At present, an SAW sensor modified by a metal oxide nanoparticle/polyacrylamide composite sensitive film prepared in situ and a preparation technology of the sensitive film are not reported.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method of an oxide nanoparticle/polyacrylamide composite sensitive film for a surface acoustic wave biosensor, wherein the preparation method adopts an electropolymerization auxiliary electrophoretic deposition method, and the sensitivity of the surface acoustic wave biosensor is improved by utilizing the large specific surface area and high biocompatibility of the oxide nanoparticle/polyacrylamide composite sensitive film; the production process is simple, the production is efficient, and the cost is low.
The invention also aims to provide the oxide nanoparticle/polyacrylamide composite sensitive film obtained by the preparation method.
The invention also aims to provide the surface acoustic wave biosensor deposited with the oxide nanoparticle/polyacrylamide composite sensitive film obtained by the preparation method.
The purpose of the invention is realized by the following technical scheme.
A preparation method of an oxide nanoparticle/polyacrylamide composite sensitive film for a surface acoustic wave biosensor comprises the following steps:
1) preparing a KCl aqueous solution with the KCl concentration of 0.04-0.06 mol/L, and uniformly dispersing an AM monomer in the KCl aqueous solution to obtain an AM aqueous solution, wherein the AM aqueous solution isAM monomer concentration of 0.9 x 10-3～5.5*10-3mol/L, wherein the AM monomer is acrylamide powder;
in the step 1), the uniform dispersion is achieved by magnetic stirring.
2) Adding 10-20 parts by mass of oxide nanoparticles into 10-20 parts by volume of the AM aqueous solution, uniformly dispersing to enable the oxide nanoparticles to be suspended in the AM aqueous solution, and adjusting the pH to 5.5-7.5 to obtain a suspension;
in the step 2), the particle size of the oxide nanoparticles is 20-50 nm.
In the step 2), 0.1mol/L disodium hydrogen phosphate aqueous solution is dripped to adjust the pH value to 5.5-7.5.
In the step 2), when the unit of the volume part is mL, the unit of the mass part is mg.
In the step 2), the oxide nanoparticles are SiO2Or Al2O3。
3) Immersing the interdigital and piezoelectric piece part of the surface acoustic wave biosensor into the suspension liquid obtained in the step 2), putting the bottom of the platinum wire into the suspension liquid obtained in the step 2), electrically connecting the surface acoustic wave biosensor and the platinum wire with an electrochemical workstation respectively, wherein the surface acoustic wave biosensor is used as a working electrode, and the platinum wire is used as a reference electrode and a counter electrode, so that the surface acoustic wave biosensor and the platinum wire form a two-electrode system;
in the step 3), the platinum wire is a straight line segment which is bent into a right angle, so that the platinum wire forms a horizontal segment and a vertical segment, and after the bottom of the platinum wire is placed in the suspension liquid obtained in the step 2), the horizontal segment of the platinum wire is partially parallel to the interdigital and the piezoelectric plate of the surface acoustic wave biosensor.
In the technical scheme, the distance between the horizontal section of the platinum wire and the interdigital and piezoelectric sheet parts of the surface acoustic wave biosensor is 1-2 cm.
In the step 3), the diameter of the platinum wire is 0.5 mm.
In the step 3), the platinum wire is polished and polished by alumina powder before use, and then is washed by nitric acid aqueous solution with the concentration of 50 wt%, ultrapure water, absolute ethyl alcohol and ultrapure water in sequence.
In the step 3), the surface acoustic wave biosensor is a single-port resonator with center frequency 433-.
In the step 3), the volume of the suspension is 10-15 mL.
4) Starting an electrochemical workstation, and depositing an oxide nanoparticle/polyacrylamide composite sensitive film on the surface acoustic wave biosensor by adopting a cyclic voltammetry method, wherein the set parameters of the electrochemical workstation are as follows: the initial potential of the working potential is-0.8V to-0.5V, the termination potential is 0.5V to 1V, the potential scanning speed range is 10 to 30mV/s, and the cycle number is 10 to 20 circles;
5) and taking out the surface acoustic wave biosensor, cleaning and drying to obtain the oxide nano-particle/polyacrylamide composite sensitive membrane on the surface acoustic wave biosensor.
In the step 5), the surface of the surface acoustic wave biosensor is washed by ultrapure water, and the surface acoustic wave biosensor is dried and placed at 35-37 ℃ for 5-10 min.
The oxide nanoparticle/polyacrylamide composite sensitive film obtained by the preparation method.
The surface acoustic wave biosensor deposited with the oxide nanoparticle/polyacrylamide composite sensitive membrane is obtained by the preparation method.
The preparation method is applied to improving the sensitivity of the sensor.
In the technical scheme, the sensor is electrically connected with the electrochemical workstation, and the sensor is used for detecting the concentration of the solution to be detected by adopting a multi-potential step method.
In the above technical scheme, the sensor is a surface acoustic wave biosensor.
In the above technical solution, the lower limit of the detection of the concentration in the solution to be detected is 10-2μM。
The invention discloses an electropolymerization-assisted electrophoretic deposition methodThe method is applied to preparing the oxide nanoparticle/polyacrylamide composite sensitive film, the PAM and the oxide nanoparticles are deposited on a surface acoustic wave biosensor (SAW device) under the action of an electric field, the direct polymerization of the sensitive film (the oxide nanoparticle/polyacrylamide composite sensitive film) and the interdigital is realized on the surface acoustic wave biosensor, the full coverage of the sensitive film on the SAW device can be realized, and the PAM and the oxide nanoparticles cannot influence the characteristic of the interdigital and cannot damage the SAW device; the electropolymerization auxiliary electrophoretic deposition method is suitable for in-situ preparation of a polymer-based composite sensitive film, the preparation method is rapid and convenient, the conditions of the growth sensitive film are changed by changing the parameters of the preparation method, so that sensitive films with different shapes and different components can be obtained, the sensitive films have good process compatibility with SAW devices, the specific surface areas of the sensitive films with different shapes are different, the adsorption capacity to biomolecules is different, the detection is more sensitive when the specific surface area is larger, the detection limit is lower, and the detection is suitable for characteristic detection of low concentration, and as can be seen from the abscisic acid detection experiment provided in the attached figure 10 of the invention, the surface acoustic wave biosensor deposited with the oxide nanoparticle/polyacrylamide composite sensitive film prepared by the method can also detect the abscisic acid with low concentration, and the concentration range of the abscisic acid in the detection experiment is 10-8～10-6mol/L, and the change of the negative frequency deviation presents a linear rule, which can prove that the lower detection limit of the surface acoustic wave biosensor of the deposited oxide nano-particle/polyacrylamide composite sensitive film prepared by the invention is very low and can be used for detecting low concentration; AM can be combined with different oxide nano-particles to generate a polymerization sensitive film with different components, thereby improving the application diversity of the invention.
Drawings
FIG. 1 is a schematic connection diagram of a two-electrode system of the present invention, wherein 1 is a platinum wire, 2 is a surface acoustic wave biosensor, 3 is an interdigital and piezoelectric plate portion, 4 is a first wire, and 5 is a second wire;
FIG. 2 is the frequency response of the SAW biosensor before and after deposition of the oxide nanoparticle/polyacrylamide composite sensing film in example 1;
FIG. 3 shows the frequency response of the SAW biosensor before and after deposition of the oxide nanoparticle/polyacrylamide composite sensing film in example 2;
FIG. 4a is an SEM photograph of interdigital under a factor of 2k of the SAW biosensor obtained in example 1;
FIG. 4b is an SEM photograph of the SAW biosensor obtained in example 1 at a magnification of 10 k;
FIG. 5a is an SEM photograph of interdigital under a multiple of 2k of the SAW biosensor obtained in example 3;
FIG. 5b is an SEM photograph of the SAW biosensor obtained in example 3 at a magnification of 10 k;
FIG. 6a is an SEM photograph of interdigital under a multiple of 2k of the surface acoustic wave biosensor obtained in example 2;
FIG. 6b is an SEM photograph of the SAW biosensor obtained in example 2 at a magnification of 10 k;
FIG. 7a is an SEM photograph of interdigital under a multiple of 2k of the SAW biosensor obtained in example 4;
FIG. 7b is an SEM photograph of the SAW biosensor obtained in example 4 at a magnification of 10k
FIG. 8a is a mapping scan of the C element of the SAW biosensor obtained in example 1;
FIG. 8b is a mapping scan of N elements of the SAW biosensor obtained in example 1;
FIG. 8c is a mapping scan of the O element of the SAW biosensor obtained in example 1;
FIG. 8d is a mapping scan of Al element of the SAW biosensor obtained in example 1;
FIG. 8e is a mapping scan of Si element of the SAW biosensor obtained in example 1;
FIG. 9a is a mapping scan of the C element of the SAW biosensor obtained in example 2;
FIG. 9b is a mapping scan of N elements of the SAW biosensor obtained in example 2;
FIG. 9c is a mapping scan of the O element of the SAW biosensor obtained in example 2;
FIG. 9d is the mapping scanning diagram of Si element of the SAW biosensor obtained in example 2;
FIG. 9e is the mapping scanning diagram of Al element in the SAW biosensor obtained in example 2;
FIG. 10 is a diagram of the negative frequency offset of the surface acoustic wave biosensor deposited with the oxide nanoparticle/polyacrylamide composite sensitive film for detecting aqueous solutions of abscisic acid of different concentrations.
Detailed Description
The technical scheme of the invention is further explained by combining specific examples.
The sources of purchase of the drugs in the following examples are as follows:
KCL was purchased from Tianjin Bodi chemical Co., Ltd;
the AM monomer is acrylamide powder with analytical purity (AR) precision grade produced by Dalochi chemical reagent factory in Tianjin;
SiO2nanoparticles were purchased from gauss nano materials equipment ltd;
disodium hydrogen phosphate was purchased from Tianjin Bailun Biotechnology, Inc.;
the following examples relate to the following instruments and models:
the model of the electrochemical workstation is 7601, Shanghai Chenghua apparatus Co., Ltd;
the model of the electric heating constant temperature incubator is DH3600BII, Tianjin Tester apparatus Co., Ltd;
the model of the network analyzer is E5070B, Agilent technologies, Inc.
The surface acoustic wave biosensor is a single-port resonator with the center frequency of 433-.
Before use, the platinum wire is polished and polished by alumina powder, and then washed by nitric acid aqueous solution with the concentration of 50 wt%, ultrapure water, absolute ethyl alcohol and ultrapure water in sequence.
Examples 1 to 4
A preparation method of an oxide nanoparticle/polyacrylamide composite sensitive film for a surface acoustic wave biosensor comprises the following steps:
1) preparing a KCl aqueous solution with the KCl concentration of 0.05mol/L, and uniformly dispersing an AM monomer in the KCl aqueous solution by magnetic stirring for 1min to obtain an AM aqueous solution, wherein the AM monomer is acrylamide powder, and the concentration of the AM monomer in the AM aqueous solution is C mol/L;
2) adding M mg of oxide nanoparticles into 20mL of AM aqueous solution, magnetically stirring for 1min to realize uniform dispersion so as to suspend the oxide nanoparticles in the AM aqueous solution, and dropwise adding 0.1mol/L of disodium hydrogen phosphate aqueous solution to adjust the pH value to P to obtain suspension;
m, C, P and oxide nanoparticles are shown in Table 1, the particle size of the oxide nanoparticles is 20-50 nm.
3) 10mL of the suspension was transferred to a 25mL electrolytic cell container, and a platinum wire with a diameter of 0.5mm was prepared, which was a straight section bent at a right angle so that the lower end of the platinum wire formed a horizontal section and the upper end of the platinum wire formed a vertical section. The interdigital and piezoelectric piece parts of a surface acoustic wave biosensor (SAW device) are downward and immersed into the suspension liquid obtained in the step 2), the bottom (lower end) of a platinum wire 1 is placed into the suspension liquid obtained in the step 2), the surface acoustic wave biosensor 2 and the platinum wire are respectively and electrically connected with an electrochemical workstation, the surface acoustic wave biosensor is used as a working electrode, an input and grounding pin of the surface acoustic wave biosensor is connected with the electrochemical workstation through a second wire 5, the platinum wire is connected with the electrochemical workstation through a first wire 4 and is used as a reference electrode and a counter electrode, so that the surface acoustic wave biosensor and the platinum wire form a two-electrode system, as shown in figure 1; after the bottom of the platinum wire is placed in the suspension liquid obtained in the step 2), the horizontal section of the platinum wire is immersed in the suspension liquid obtained in the step 2) and is parallel to the interdigital and piezoelectric plate part 3 of the surface acoustic wave biosensor, and the distance between the horizontal section of the platinum wire and the interdigital and piezoelectric plate parts of the surface acoustic wave biosensor is 1 cm.
4) Starting an electrochemical workstation, and depositing an oxide nanoparticle/polyacrylamide composite sensitive film on the surface acoustic wave biosensor by adopting a cyclic voltammetry method, wherein the set parameters of the electrochemical workstation are as follows: the initial potential of the working potential is-0.5V, the final potential is 0.5V, the potential scanning speed range is 10mV/s, the cycle number is 10 circles, and the direction of the external electric field points to the platinum wire from the SAW device.
5) And taking out the surface acoustic wave biosensor, washing the surface of the surface acoustic wave biosensor with ultrapure water, placing the surface acoustic wave biosensor in an electrothermal constant temperature incubator at 37 ℃ for 5min, and obtaining the oxide nanoparticle/polyacrylamide composite sensitive film on the surface acoustic wave biosensor.
TABLE 1
| Examples | Oxide nanoparticles | P | C | M |
| Example 1 | SiO2 | 6.5 | 10-3 | 20mg |
| Example 2 | Al2O3 | 6.3 | 10-3 | 20mg |
| Example 3 | SiO2 | 6.5 | 5*10-3 | 20mg |
| Example 4 | Al2O3 | 6.3 | 10-3 | 10mg |
And (3) testing the surface acoustic wave biosensor obtained in the embodiment 1-4 by using a network analyzer, observing the change of the front and back central frequencies and the loss of the surface acoustic wave biosensor in the preparation method, and when the central frequency changes, proving that the oxide nanoparticle/polyacrylamide composite sensitive membrane is successfully prepared.
FIG. 2 is a graph showing frequency responses before and after deposition of an oxide nanoparticle/polyacrylamide composite sensitive film in the surface acoustic wave biosensor in example 1, where the surface acoustic wave biosensor without the oxide nanoparticle/polyacrylamide composite sensitive film deposited is a SAW bare part, and the surface acoustic wave biosensor with the oxide nanoparticle/polyacrylamide composite sensitive film deposited is a SiO2PAW/SAW, the center frequency of the single-port resonator of the surface acoustic wave biosensor before and after electropolymerization can be seen to shift, and the fact that the oxide nano-particle/polyacrylamide composite sensitive film is polymerized on the surface acoustic wave biosensor can be proved.
FIG. 3 is a diagram illustrating frequency responses before and after deposition of an oxide nanoparticle/polyacrylamide composite sensitive film in the surface acoustic wave biosensor in accordance with example 2, where the surface acoustic wave biosensor without the oxide nanoparticle/polyacrylamide composite sensitive film deposited thereon is a SAW bare part, and the surface acoustic wave biosensor with the oxide nanoparticle/polyacrylamide composite sensitive film deposited thereon is a SiO2PAW/SAW, the center frequency of the single-port resonator of the surface acoustic wave biosensor is shifted before and after electropolymerization, and oxygen can be provedThe compound nano-particle/polyacrylamide composite sensitive film is polymerized on a surface acoustic wave biosensor.
Fig. 4a is an SEM photograph of the surface acoustic wave biosensor obtained in example 1 under a magnification of 2k, and fig. 4b is an SEM photograph of the surface acoustic wave biosensor obtained in example 1 under a magnification of 10k, which shows that direct polymerization of the interdigital and the oxide nanoparticle/polyacrylamide composite sensitive film has been achieved, the oxide nanoparticle/polyacrylamide composite sensitive film is wrapped on the surface of the interdigital, and the interdigital structure is intact.
Fig. 5a is an SEM photograph of the surface acoustic wave biosensor obtained in example 3 under a 2k multiple, and fig. 5b is an SEM photograph of the surface acoustic wave biosensor obtained in example 3 under a 10k multiple, as can be seen from comparison with fig. 4a and 4b, the difference in the concentration of the AM aqueous solution affects the morphology of the composite sensitive film after electropolymerization, and the difference in the concentration of the AM and the binding strength with the oxide nanoparticles are different, thereby affecting the strength of polymerization onto the SAW interdigital to form different morphological features.
Fig. 6a is an SEM photograph of the surface acoustic wave biosensor obtained in example 2 under a magnification of 2k, and fig. 6b is an SEM photograph of the surface acoustic wave biosensor obtained in example 2 under a magnification of 10k, which shows that the direct polymerization of the interdigital and the oxide nanoparticle/polyacrylamide composite sensitive film has been achieved, the oxide nanoparticle/polyacrylamide composite sensitive film is wrapped on the surface of the interdigital, and the interdigital structure is intact.
Fig. 7a is an SEM photograph of the surface acoustic wave biosensor obtained in example 4 under 2k times of interdigital, fig. 7b is an SEM photograph of the surface acoustic wave biosensor obtained in example 4 under 10k times of interdigital, and comparing with fig. 6a and 6b, it can be seen that the difference in the content of oxide nanoparticles affects the morphology of the electropolymerized composite sensitive film, the oxide nanoparticles can increase the specific surface area, and the coverage of the sensitive film is easy, and the more the oxide nanoparticles, the larger the adhesive force, the larger the specific surface area, and thus the morphology of the sensitive film is affected.
FIGS. 8a to 8e are mapping scanning charts of the SAW biosensor obtained in example 1, and FIGS. 8a to 8e are successively a SAW biosensor in the order namedMapping scanning graph of C, N, O, Al and Si elements of the device shows that C, N elements and SiO contained in AM monomer2Si and O elements in the nano particles are completely attached to the surface of the electrode and are distributed very uniformly, so that the oxide nano particle/polyacrylamide composite sensitive film is proved to be generated on the surface acoustic wave biosensor.
FIGS. 9a to 9e are mapping scans of the SAW biosensor obtained in example 2, and FIGS. 9a to 9e are mapping scans of C, N, Ol, Si and Al elements of the SAW biosensor, respectively, and it can be seen from these views that the AM monomer contains C, N element and Al element2O3Al and O elements in the nano particles are completely attached to the surface of the electrode and are distributed very uniformly, so that the oxide nano particle/polyacrylamide composite sensitive film generated on the surface acoustic wave biosensor (SAW device) is proved.
FIG. 10 is a graph showing the negative frequency shift of the SAW biosensor prepared in example 1, measured with aqueous solutions of different concentrations of abscisic acid, where the range of the concentration of abscisic acid in the measured aqueous solution of abscisic acid is 10-21 μ M (i.e., 10)-8～10-6mol/L), the detection process of the abscisic acid aqueous solution with each concentration is as follows: 10mL of the abscisic acid aqueous solution with the concentration is added into a beaker, the surface of the SAW device deposited with the oxide nanoparticle/polyacrylamide sensitive film obtained in example 1 is immersed into the abscisic acid aqueous solution, the SAW device is used as a working electrode, the input and grounding pins of the device are connected with an electrochemical workstation through a second wire 5, a platinum wire is connected with the electrochemical workstation through a first wire 4 and is used as a reference electrode and a counter electrode, so that the surface acoustic wave biosensor and the platinum wire form a two-electrode system, wherein the platinum wire is a straight line segment which is bent into a right angle to form a horizontal segment and a vertical segment, after the bottom of the platinum wire is put into the abscisic acid aqueous solution, the horizontal section of the platinum wire is parallel to the interdigital and piezoelectric sheet part 3 of the surface acoustic wave biosensor, and the distance between the horizontal section of the platinum wire and the interdigital and piezoelectric sheet part of the surface acoustic wave biosensor is 1 cm. Adopting a multi-potential step method in an electrochemical workstation to detect abscisic acid, setting the first step potential and the step time to be-0.3V and 5s, and setting the second step potential and the step time to be-0.3V and 5sThe bit and step time are set to 0.3V and 1s, and the cycle time is 8 times; and after the surface of the SAW device to be detected with the abscisic acid is dried, detecting the SAW device by using a network analyzer, and proving that the abscisic acid aqueous solution is successfully detected by reducing the central frequency of the SAW device after the abscisic acid aqueous solution is detected.
FIG. 10 shows the abscissa of the logarithm of the concentration of the aqueous solution of abscisic acid, and represents N (i.e., the concentration of the aqueous solution of abscisic acid is 10)Nμ M), the ordinate is the central frequency difference between the SAW device after detecting the abscisic acid aqueous solution with corresponding concentration and the SAW device which is not detected at the beginning, and is set as negative frequency deviation; as can be seen from FIG. 10, when the concentration of the aqueous abscisic acid solution to be detected was 10-2When the concentration of the abscisic acid in the aqueous solution of the abscisic acid is lower than the preset value, the negative frequency deviation is-0.0175 MHz, the negative frequency deviation is increased along with the increase of the concentration of the abscisic acid in the aqueous solution of the abscisic acid, and the linear fitting of a curve can show that the negative frequency deviation is in a linear rule, so that the negative frequency deviation is proved to be related to the concentration of the abscisic acid in the aqueous solution of the abscisic acid, and the detection method is real and feasible; the surface acoustic wave biosensor prepared by the method has low detection limit, can be used for low-concentration detection, and improves the sensitivity of SAW devices.
The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.
Claims (10)
1. A preparation method of an oxide nanoparticle/polyacrylamide composite sensitive film for a surface acoustic wave biosensor is characterized by comprising the following steps:
1) preparing a KCl aqueous solution with the KCl concentration of 0.04-0.06 mol/L, and uniformly dispersing an AM monomer in the KCl aqueous solution to obtain an AM aqueous solution, wherein the AM monomer concentration in the AM aqueous solution is 0.9 x 10-3～5.5*10-3mol/L, wherein the AM monomer is acrylamide powder;
2) adding 10-20 parts by mass of oxide nanoparticles into 10-20 parts by volume of the AM aqueous solution, uniformly dispersing to enable the oxide nanoparticles to be suspended in the AM aqueous solution, and adjusting the pH to 5.5-7.5 to obtain a suspension;
3) immersing the interdigital and piezoelectric piece parts of the surface acoustic wave biosensor into the suspension liquid obtained in the step 2), putting the bottom of a platinum wire into the suspension liquid obtained in the step 2), and electrically connecting the surface acoustic wave biosensor and the platinum wire with an electrochemical workstation respectively, wherein the surface acoustic wave biosensor is used as a working electrode, and the platinum wire is used as a reference electrode and a counter electrode, so that the surface acoustic wave biosensor and the platinum wire form a two-electrode system;
4) starting an electrochemical workstation, and depositing an oxide nanoparticle/polyacrylamide composite sensitive film on the surface acoustic wave biosensor by adopting a cyclic voltammetry method, wherein the set parameters of the electrochemical workstation are as follows: the initial potential of the working potential is-0.8V to-0.5V, the termination potential is 0.5V to 1V, the potential scanning speed range is 10 to 30mV/s, and the cycle number is 10 to 20 circles;
5) and taking out the surface acoustic wave biosensor, cleaning and drying to obtain the oxide nano-particle/polyacrylamide composite sensitive membrane on the surface acoustic wave biosensor.
2. The method according to claim 1, wherein in the step 1), the uniform dispersion is achieved by magnetic stirring.
3. The method according to claim 2, wherein in the step 2), the oxide nanoparticles have a particle size of 20 to 50 nm;
in the step 2), dropwise adding 0.1mol/L disodium hydrogen phosphate aqueous solution to adjust the pH value to 5.5-7.5;
in the step 2), when the unit of the volume part is mL, the unit of the mass part is mg;
in the step 2), the oxide nanoparticles are SiO2Or Al2O3。
4. The preparation method according to claim 3, wherein in the step 3), the platinum wire is a straight line segment which is bent into a right angle, so that the platinum wire forms a horizontal segment and a vertical segment, after the bottom of the platinum wire is placed in the suspension obtained in the step 2), the horizontal segment of the platinum wire is parallel to the interdigital and piezoelectric plate portion of the surface acoustic wave biosensor, and the distance between the horizontal segment of the platinum wire and the interdigital and piezoelectric plate portion of the surface acoustic wave biosensor is 1-2 cm.
5. The production method according to claim 4, wherein in the step 3), the platinum wire has a diameter of 0.5 mm;
in the step 3), the platinum wire is polished and polished by alumina powder before use, and then is sequentially washed by nitric acid aqueous solution with the concentration of 50 wt%, ultrapure water, absolute ethyl alcohol and ultrapure water;
in the step 3), the surface acoustic wave biosensor is a single-port resonator with center frequency 433-;
in the step 3), the volume of the suspension is 10-15 mL.
6. The method according to claim 5, wherein in the step 5), the cleaning is to rinse the surface of the surface acoustic wave biosensor with ultrapure water, and the drying is to leave the surface acoustic wave biosensor at 35-37 ℃ for 5-10 min.
7. The oxide nanoparticle/polyacrylamide composite sensitive film obtained by the preparation method according to any one of claims 1-6.
8. The surface acoustic wave biosensor deposited with the oxide nanoparticle/polyacrylamide composite sensitive film, obtained by the preparation method of any one of claims 1-6.
9. Use of the preparation method according to any one of claims 1 to 6 for improving the sensitivity of a sensor.
10. The use according to claim 9, characterized in that a sensor is electrically connected to the electrochemical workstation, the sensor being used to detect the concentration of the solution to be tested by means of a multi-potential step method;
the sensor is a surface acoustic wave biosensor;
the lower detection limit of the concentration in the solution to be detected is 10-2μM。
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| CN101971012A (en) * | 2007-12-20 | 2011-02-09 | 雅培医护站股份有限公司 | Formation of immobilized biological layers for sensing |
| CN106979975A (en) * | 2017-03-14 | 2017-07-25 | 天津理工大学 | A kind of electrochemical in-situ preparation method of surface acoustic wave biological sensor sensing film |
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| CN101971012A (en) * | 2007-12-20 | 2011-02-09 | 雅培医护站股份有限公司 | Formation of immobilized biological layers for sensing |
| CN106979975A (en) * | 2017-03-14 | 2017-07-25 | 天津理工大学 | A kind of electrochemical in-situ preparation method of surface acoustic wave biological sensor sensing film |
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| 声表面波分子印迹技术检测甲基膦酸二甲酯的研究;潘勇;《分析测试学报》;20050731;第42-44页 * |
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