Miniaturized water quality sensor chip with antifouling function and preparation method thereof

Abstract

The invention relates to a miniaturized water quality sensor chip with an antifouling function and a preparation method of the miniaturized water quality sensor chip. The preparation method comprises the following steps: firstly, immersing the miniaturized water quality sensor chip into a macromolecular initiator solution; the macroinitiator spontaneously adheres to various substrates on the surface of a microminiaturized water quality sensor chip, so that a layer of macroinitiator is modified on each substrate, and then a zwitter-ion functionalized polymer is initiated, polymerized and grafted on the substrate modified with the macroinitiator to form a zwitter-ion functionalized antifouling coating. The micro water quality sensor chip with the antifouling function is prepared; the zwitter-ion functional antifouling coating is arranged on the substrate on the surface of the prepared miniaturized water quality sensor chip with the antifouling function. The product provided by the invention has the characteristics of miniaturization and integration, also has excellent antifouling performance, can effectively resist the attachment of sediments and organisms, and reduces the interference of pollutants; the preparation method disclosed by the invention can be used for simultaneously carrying out antifouling treatment on various substrates of the miniaturized water quality sensor chip.

Description

Technical Field

[0001] The invention belongs to the technical field of water quality detection sensors and relates to a miniaturized water quality sensor chip with an anti-fouling function and a preparation method thereof. Background Art

[0002] With the rapid development of industrialization and urbanization, the pollution of water resources has become increasingly prominent, and the demand for water quality monitoring has become more and more urgent. Multi-parameter water quality sensors are widely used in the field of water environment monitoring because they can simultaneously monitor multiple water quality indicators, such as pH, dissolved oxygen, temperature, etc. However, existing commercial water quality testing equipment has problems such as large size, fewer detection parameters, high cost, and complex structure, which makes it difficult to accurately detect the water quality of water environments such as tap water and household sewage. At the same time, there are some problems with multi-parameter water quality sensors during long-term use: First, the working stability of the sensor chip is affected by environmental pollution. For example, sediments and biological attachment in the water body will cause the sensor readings to drift, thereby affecting the accuracy of the monitoring data. Secondly, some water quality sensor chips are easily interfered by pollutants in complex water quality environments, resulting in large errors or even loss of monitoring capabilities.

[0003] There have been some attempts to improve the anti-fouling problem of water quality sensor chips and to miniaturize the design of water quality testing equipment.

[0004] Reference 1 (Anal. Chem. 2019, 91(16): 10524–10531) uses silicone rubber as the outer coating of a PVC-based K+ selective electrode. After adding silicone rubber coating to the K+ selective membrane, ellipsometry analysis showed that the amount of BSA adsorbed by silicone rubber was only half of that of the PVC-based membrane, indicating that the silicone rubber coating can improve the anti-fouling property of the sensor.

[0005] Reference 2 (IEEE Sensors Journal, 2014, 14(10): 3400-3407) uses polydimethylsiloxane (PDMS) to make an oxygen permeable membrane. In order to improve the anti-fouling performance of the oxygen permeable membrane, plasma irradiation is used to generate a large number of hydroxyl groups on its surface, and 3-aminopropyltriethoxysilane (APTES) is fixed on the PDMS surface by reacting the hydroxyl group with the ethoxy group. Then, the APTES amino group and the carboxyl group are used to cap the PEG chain and graft PEG. A heme-based dissolved oxygen sensor with anti-biological contamination is successfully prepared.

[0006] In general, the current improvement of the antifouling performance of miniaturized water quality sensor chips is mostly to modify the material on the sensitive layer of a single electrode for performance verification, without considering that in actual applications, the surface of the miniaturized water quality sensor chip involves multiple substrates, such as electrode substrate, encapsulation layer substrate and sensitive layer substrate, and multiple substrates need to be antifouling. In addition, there is a problem with the surface coating method used in document 1, that is, the interaction between the substrate and the coating is relatively weak, which causes the coating to easily fall off the membrane surface, thereby reducing the antifouling performance. Therefore, it is not suitable for the antifouling improvement of miniature water quality sensor chips. The traditional surface grafting method used in document 2 requires the introduction of reactive groups on the material surface in advance before grafting, which increases the complexity of the modification process. In addition, the reactive groups cannot be introduced simultaneously on the different substrate surfaces of the miniaturized water quality sensor chip due to different materials, resulting in the inability to simultaneously perform antifouling modification on multiple substrates. In addition, the use of organic solvents damages the sensitive layer, so it is also not suitable for the antifouling improvement of miniature water quality sensor chips.

[0007] Although existing commercial sensors also process multiple substrates of multiple sensor chips, for example, reference 3 (Sensors 2021, 21(2), 389; doi.org / 10.3390 / s21020389) summarizes the commonly used anti-fouling methods for current commercial water quality sensors, including the wiper method, the bactericide method, etc.

[0008] The wiper method is a method of removing surface dirt by physical scraping, which is often used in large water quality sensor equipment. However, the size of miniaturized water quality sensors is small, often much smaller than traditional water quality sensors, which makes it difficult to install complex mechanical wiper devices on the sensor surface. Due to limited space, it is difficult to accommodate larger mechanical components, so it is difficult to apply to miniaturized water quality sensor chips. At the same time, this method is prone to damage the sensor surface, and has limited cleaning effect on small structures or pores that are difficult to clean.

[0009] The bactericide method inhibits bacterial growth and reduces scale formation by adding bactericides (such as quaternary ammonium compounds and halogens). This method can effectively reduce the adhesion and adhesion of bacteria, thereby reducing the accumulation of scale. Although it can be applied to miniaturized water quality sensor chips, some bactericides pose potential risks to the environment and human health and need to be strictly evaluated.

[0010] Therefore, it is of great significance to study a miniaturized water quality sensor chip with anti-fouling function and a preparation method thereof so as to simultaneously perform anti-fouling treatment on multiple substrates of the miniaturized water quality sensor chip, which is green and environmentally friendly. Summary of the invention

[0011] The purpose of the present invention is to solve the problems existing in the prior art and to provide a miniaturized water quality sensor chip with anti-fouling function and a preparation method thereof.

[0012] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0013] A method for preparing a miniaturized water quality sensor chip with an antifouling function, firstly immersing the miniaturized water quality sensor chip in a macromolecular initiator solution, wherein the macromolecular initiator spontaneously adheres to a variety of substrates (such as an electrode substrate, a packaging layer substrate, a sensitive layer substrate, etc.) on the surface of the miniaturized water quality sensor chip, thereby modifying a layer of macromolecular initiator on the substrate, and then initiating polymerization on the substrate after the modification of the macromolecular initiator to graft a zwitterionic functionalized polymer to form a zwitterionic functionalized antifouling coating, thereby preparing a miniaturized water quality sensor chip with an antifouling function;

[0014] The macromolecular initiator solution is obtained by dissolving the macromolecular initiator in a buffer solution having a pH of 3.7 to 5.5;

[0015] The time for the macromolecular initiator to spontaneously adhere and modify is 1 to 5 minutes;

[0016] The chemical structure of the macroinitiator is shown in formula (A);

[0017]

[0018] Where:

[0019] m, n, z are positive integers, and 1≤m≤50000, 1≤n≤50000, 1≤z≤50000, m / (m+n+z)=0.1%~99.9%, n / (m+n+z)=0.1%~99.9%, z / (m+n+z)=0.1%~99.9%;

[0020] R1, R2, and R3 are independently any one of -H, -CH3, -NH2, -OH, -COOH, and --SH;

[0021] R4, R5, and R7 are independently -H, --(CH) d Any one of CH3, wherein d is a positive integer and 0≤d≤8;

[0022] R6-X is -X, Any one of, wherein X is any one of Br, Cl, I;

[0023] R8 is Any one of , where c is a positive integer and 1≤c≤30;

[0024] L1 and L2 are independently -CO-O-(CH2) a -、-O-CO-(CH2) a -、-NH-CO-(CH2) a -、-CO-NH-CO-(CH2) a -、-CO-NH-(CH2) a -O-CO-, -NH-CO-(CH2) a -O-CO-, -CO-O-(CH2) a -O-CO-, -O-CO-(CH2) a -O-CO-, -CO-O-(CH2) a -NH-CO-, -O-CO-(CH2) a -NH-CO-, -CO-NH-(CH2) a -NH-CO-, -NH-CO-(CH2) a Any one of -NH-CO-, wherein a is a positive integer, and 0≤a≤8.

[0025] As the preferred technical solution:

[0026] The method for preparing a miniaturized water quality sensor chip with anti-fouling function as described above, wherein the substrate comprises an electrode substrate, a packaging layer substrate and a sensitive layer substrate;

[0027] The electrode substrate material is gold, platinum, graphene, carbon nanotubes, metal nanowires or conductive polymers;

[0028] The base material of the encapsulation layer is polyparaxylene, polydimethylsiloxane, polyurethane or polyimide;

[0029] The substrate material of the sensitive layer is polyvinyl chloride, metal nanoparticles, carbon nanotubes, graphene or conductive polymer.

[0030] The method for preparing a miniaturized water quality sensor chip with an anti-fouling function as described above, the specific steps for preparing the miniaturized water quality sensor chip with an anti-fouling function are as follows:

[0031] (1) first dissolving the macromolecular initiator in a buffer solution with a pH of 3.7 to 5.5 to obtain a macromolecular initiator solution with a concentration of 0.1 to 5 mg / mL, and then immersing the miniaturized water quality sensor chip in the macromolecular initiator solution for 1 to 5 minutes to complete the macromolecular initiator modification;

[0032] (2) The zwitterionic polymer chain was grafted onto the macromolecular initiator by atom transfer radical polymerization to form a zwitterionic functional antifouling coating on the surface substrate of the miniaturized water quality sensor chip. After rinsing with deionized water and drying with nitrogen, a miniaturized water quality sensor chip with antifouling function was prepared.

[0033] In the method for preparing a miniaturized water quality sensor chip with anti-fouling function as described above, the buffer solution in step (1) is an acetic acid buffer solution.

[0034] In the method for preparing a miniaturized water quality sensor chip with antifouling function as described above, the process of forming a zwitterion functional antifouling coating on the substrate on the surface of the miniaturized water quality sensor chip in step (2) is as follows: adding a catalyst, a ligand, a zwitterion monomer and a miniaturized water quality sensor chip modified with a macromolecular initiator to a solvent, performing atom transfer radical polymerization under the protection of a N2 atmosphere, and forming a zwitterion functional antifouling coating on the substrate on the surface of the miniaturized water quality sensor chip;

[0035] The molar ratio of the catalyst to the ligand is 1:1-8; the concentration of the zwitterionic monomer after being dissolved in the solvent is 10-5000 mM; the concentration of the macromolecular initiator after being dissolved in the solvent is 1-10 mol% of the concentration of the zwitterionic monomer after being dissolved in the solvent.

[0036] In the method for preparing a miniaturized water quality sensor chip with antifouling function as described above, the temperature of the atom transfer radical polymerization is 10-100° C. and the time is more than 1 hour.

[0037] The method for preparing a miniaturized water quality sensor chip with an antifouling function as described above, the preparation process of the macromolecular initiator is: preparing a mixed solvent, adding a thermal initiator, monomer I, monomer II and monomer III to the mixed solvent, reacting under the protection of a N2 atmosphere, and dialyzing and freeze-drying the product after the reaction to obtain the macromolecular initiator;

[0038] The mixed solvent is dimethylformamide (DMF) / water, dimethylformamide (DMF) / methanol, dimethyl sulfoxide (DMSO) / water or dimethyl sulfoxide (DMSO) / methanol;

[0039] The thermal initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate and azobisisobutylamidine hydrochloride;

[0040] The chemical structures of monomer I, monomer II and monomer III are shown in formula (B), (C) and (D), respectively;

[0041]

[0042] In the method for preparing a miniaturized water quality sensor chip with anti-fouling function as described above, the reaction temperature is 10 to 100° C. and the reaction time is 0.1 to 5 hours.

[0043] The method for preparing a miniaturized water quality sensor chip with antifouling function as described above, based on the total amount of monomer I, monomer II, and monomer III, the molar percentage of monomer I is 1% to 50%, the molar percentage of monomer II is 1% to 20%, and the molar percentage of monomer III is 30% to 98%;

[0044] The molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.001-1;

[0045] The total concentration of monomer I, monomer II and monomer III after being dissolved in the mixed solvent is 0.1-1000 mg / mL.

[0046] The present invention also provides a miniaturized water quality sensor chip with antifouling function prepared by the method described in any one of the above, wherein the surface substrate of the miniaturized water quality sensor chip with antifouling function has a zwitterion functionalized antifouling coating, and the chemical structure of the zwitterion functionalized antifouling coating is:

[0047]

[0048] Wherein: y is a positive integer, and 1≤y≤50000.

[0049] Principle of the invention:

[0050] The present invention adopts a novel method to improve the antifouling performance of a water quality sensor. First, a macromolecular initiator that can adhere to a variety of substrates is synthesized. The initiator combines a zwitterion-modified monomer, a dopamine-modified monomer and a graft polymerization initiator functionalized monomer. The strong adhesion of dopamine is used to modify the initiator on the surface of a water quality sensor chip. Subsequently, a zwitterion polymer chain is grafted on the surface of the sensor chip by a graft polymerization method to prepare a zwitterion functionalized antifouling coating.

[0051] The dopamine component in the macromolecular initiator contains catechol functional groups in its molecular structure, which makes it have excellent self-adhesion properties and can adhere to various substrates of the water quality sensor chip to achieve the modification of the macromolecular initiator (the principle of self-adhesion of the dopamine structure is: the dopamine structure contains catechol groups and benzene rings, etc., and can achieve self-adhesion on the surface of multiple substrates through hydrogen bonds, cation-π, π-π stacking, hydrophobic interactions, etc.); at the same time, the excellent hydrophilicity of the zwitterionic group of the macromolecular initiator promotes the dissolution of the macromolecular initiator in aqueous solution, so that no additional organic solvent is required, that is, the macromolecular initiator can be quickly modified on the surface of the water quality sensor chip, and the modification of the macromolecular initiator can be completed in only 1 to 5 minutes. The pH value of the solution also affects the adhesion of the macromolecular initiator. The QCM experiment verified that the macromolecular initiator showed excellent adhesion in the buffer solution with a pH of 3.7 to 5.5. This is because the charge state and chemical structure of the dopamine structure will also change under different pH conditions, thus affecting the interaction mode with the surface functional groups. At a pH of 3.7 to 5.5, the structure of the dopamine molecule can interact with the surface through hydrogen bonds and hydrophobic interactions. After dopamine is ionized, charged ions are formed, and there is a π-π interaction, which is beneficial to the adhesion performance. In addition, when the solution is alkaline, the dopamine structure is easily oxidized to dopaquinone, resulting in weakened adhesion. Therefore, the charge state and chemical structure of the dopamine structure can be adjusted by adjusting the pH value of the solution to regulate its adhesion performance on the surface of the object.

[0052] The grafted polymerization initiator functionalized monomer in the macromolecular initiator can further initiate the grafted polymerization of the grafted zwitterionic polymer. The zwitterionic polymer and the zwitterionic groups in the macromolecular initiator have a synergistic effect on the improvement of antifouling performance. Specifically, the zwitterionic groups in the macromolecular initiator have excellent hydrophilicity, which helps to improve the hydrophilicity of the coating surface, making it difficult for water and pollutants to adhere to the surface; and when the zwitterionic polymer chains are grafted by grafting polymerization, the excellent hydrophilicity of the bottom layer is more conducive to the expansion of the upper zwitterionic polymer chains, and its molecular structure is more diverse, which increases the interaction with water molecules and further improves the hydrophilicity of the coating. Because the zwitterionic polymer and the zwitterionic groups in the macromolecular initiator give the coating excellent hydrophilicity, it can effectively reduce the adhesion of pollutants such as proteins and microorganisms on the surface, and improve the antifouling performance of the water quality sensor chip.

[0053] In summary, the present invention achieves anti-fouling modification on multiple substrate surfaces of water quality sensor chips by cleverly designing macromolecular initiators and functional anti-fouling coatings, utilizing the self-adhesion of dopamine and the hydrophilicity of zwitterionic polymers. This anti-fouling coating has good stability and is not easy to fall off, thereby significantly improving the long-term monitoring capability of the miniaturized water quality sensor chip in complex water environments.

[0054] Beneficial effects:

[0055] (1) The miniaturized water quality sensor chip with anti-fouling function of the present invention has the characteristics of miniaturization and integration, and has excellent anti-fouling performance, which can effectively resist the attachment of sediments and organisms and reduce the interference of pollutants;

[0056] (2) The method for preparing a miniaturized water quality sensor chip with antifouling function of the present invention can simultaneously perform antifouling treatment on multiple substrates of the miniaturized water quality sensor chip;

[0057] (3) The zwitterion-functionalized antifouling coating of the miniaturized water quality sensor chip with antifouling function of the present invention has good stability and is not easy to fall off, thereby significantly improving the long-term monitoring capability of the miniaturized water quality sensor chip in a complex water environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a schematic diagram of the macroinitiator synthesis process of Example 1;

[0059] Figure 2 The macromolecular initiator of Example 1 1 H NMR spectrum;

[0060] Figure 3 This is a schematic diagram of the preparation process of a miniaturized multi-parameter water quality sensor chip with anti-fouling function according to Example 7;

[0061] Figure 4 The adhesion curves of macromolecular initiators with different DMA feeds on different substrates when the MBR content remains unchanged. Figure a) is a pure gold substrate, Figure b) is a parylene substrate; Figure c) is a PVC substrate;

[0062] Figure 5 These are the anti-BSA adhesion curves of macromolecular initiators with different DMA feeds on different substrates. Figure a) is a pure gold substrate, Figure b) is a parylene substrate; Figure c) is a PVC substrate;

[0063] Figure 6 The adhesion curves of different substrates modified by macromolecular initiators in buffer solutions with different pH values ​​are shown in Figure a) for pure gold substrate, Figure b) for parylene substrate, and Figure c) for PVC substrate.

[0064] Figure 7 It is a comparison diagram of the effects of the unmodified, macromolecular initiator-modified and ATRP-grafted zwitterion functionalized antifouling coatings of Example 7 on the contact angles of pure gold substrate, PVC substrate and Parylene substrate;

[0065] Figure 8Microscope images of fluorescent protein (FITC-BSA) adhered to the surface of different types of water quality sensor chips, Figure a) and Figure d) are local and fluorescence microscope images of FITC-BSA adhered to the surface of unmodified water quality sensor chip, Figure b) and Figure e) are local and fluorescence microscope images of FITC-BSA adhered to the surface of water quality sensor chip modified with macromolecular initiator, Figure c) and Figure f) are local and fluorescence microscope images of FITC-BSA adhered to the surface of water quality sensor chip modified with zwitterion functionalized antifouling coating, respectively;

[0066] Fig. 9 The comparison diagrams of sensitivity changes of different sensors before and after modification of zwitterion functionalized antifouling coatings and the comparison diagrams of conductivity cell coefficient K changes of conductivity sensors are shown in Figure a) for pH sensors, Figure b) for ammonia nitrogen sensors, and Figure c) for dissolved oxygen sensors;

[0067] Fig.10 It is a comparison diagram of the anti-BSA adhesion curves of the miniaturized water quality sensor chip. Figure a) is the anti-BSA adhesion curve of the pure gold substrate modified by the zwitterion functionalized antifouling coating at different reaction times, Figure b) is the anti-BSA adhesion curve of the pure gold substrate surface modified by the macromolecular initiator and the zwitterion functionalized antifouling coating, Figure c) is the anti-BSA adhesion curve of the parylene substrate surface modified by the macromolecular initiator and the zwitterion functionalized antifouling coating; Figure d) is the anti-BSA adhesion curve of the PVC substrate surface modified by the macromolecular initiator and the zwitterion functionalized antifouling coating;

[0068] Fig.11 The figures are comparison graphs of the sensitivity of pH, ammonia nitrogen, and dissolved oxygen sensors and the conductivity cell coefficient K of the conductivity sensor in different complex water environments before and after modification with zwitterion functionalized antifouling coating. Figure a) and Figure b) are comparison graphs of the sensitivity changes of the pH sensor in pond water and BSA solution before and after modification with zwitterion functionalized antifouling coating, respectively. Figure c) and Figure d) are comparison graphs of the sensitivity changes of the ammonia nitrogen sensor in pond water and BSA solution before and after modification with zwitterion functionalized antifouling coating, respectively. Figure e) and Figure f) are comparison graphs of the sensitivity changes of the dissolved oxygen sensor in pond water and BSA solution before and after modification with zwitterion functionalized antifouling coating, respectively. Figure g) and Figure h) are comparison graphs of the sensitivity changes of the integrated conductivity sensor in pond water and BSA solution before and after modification with zwitterion functionalized antifouling coating, respectively. DETAILED DESCRIPTION

[0069] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0070] In order to verify the adhesion and anti-adhesion properties of the material, the present invention adopts QCM test, and the specific test method is as follows (taking the adhesion performance experiment of the macromolecular initiator p(DMA-co-MPC-co-MBR) as an example): the macromolecular initiator is dissolved in an acetate buffer with a pH of 5.5 to prepare a macromolecular initiator buffer with a concentration of 1 mg / ml; the flow order of the QCM solution is: ① flow blank buffer for 10 minutes; ② flow the macromolecular initiator buffer for another 30 minutes; ③ finally flow blank buffer for 10 minutes; the buffer flow rate is 30 μL / min, and the frequency and dissipation changes of the third order of the QCM chip are taken as the final test results.

[0071] The modification time of the macromolecular initiator is obtained by calculating the time of the QCM chip frequency change.

[0072] Example 1

[0073] A method for preparing a macromolecular initiator, such as Figure 1 As shown, the specific steps are as follows:

[0074] (1) Preparation of raw materials:

[0075] The thermal initiator was azobisisobutyronitrile (AIBN);

[0076] The mixed solvent was dimethylformamide / water in a volume ratio of 4:1;

[0077] Monomer I: Chemical structure is

[0078] Monomer II: Chemical structure is

[0079] Monomer III: Chemical structure is

[0080] (2) adding a thermal initiator, monomer I, monomer II and monomer III into a mixed solvent, reacting at 75° C. for 3 h under N2 atmosphere protection, dialyzing the product after the reaction, and freeze-drying it at -40° C. for 48 h to obtain a macromolecular initiator p (DMA-co-MBR-co-MPC);

[0081] Wherein, based on the total amount of monomer I, monomer II and monomer III, the molar percentage of monomer I is 30%, the molar percentage of monomer II is 10%, and the molar percentage of monomer III is 60%; the molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.001; the total concentration of monomer I, monomer II and monomer III after being dissolved in a mixed solvent is 150 mg / mL.

[0082] like Figure 2 As shown, the chemical structure of the macromolecular initiator is:

[0083] The macromolecular initiator prepared above was dissolved in an acetate buffer solution with a pH of 3.7 to obtain a macromolecular initiator solution with a concentration of 1 mg / mL; the modification time of the macromolecular initiator on different substrates was investigated by QCM experiment, and the modification time required for the gold substrate was 80 s, the modification time required for the parylene substrate was 110 s, and the modification time required for the PVC substrate was 276 s;

[0084] The macroinitiator prepared above was dissolved in an acetate buffer solution with a pH of 4 to obtain a macroinitiator solution with a concentration of 1 mg / mL; the modification time of the macroinitiator on different substrates was investigated by QCM experiment, with the modification time of gold substrate being 80 s, parylene substrate being 231 s, and PVC substrate being 177 s;

[0085] The macroinitiator prepared above was dissolved in an acetate buffer solution with a pH of 5.5 to obtain a macroinitiator solution with a concentration of 1 mg / mL. The modification time of the macroinitiator on different substrates was investigated by QCM experiment. The modification time of the gold substrate was 117 s, the modification time of the parylene substrate was 123 s, and the modification time of the PVC substrate was 98 s.

[0086] like Figure 6 As shown, the macromolecular initiator exhibited adhesion on all three substrates, and the frequency decrease of the macromolecular initiator was the largest in the acetate buffer solution with a pH of 4.0, indicating that at this pH value, the macromolecular initiator exhibited excellent substrate adhesion.

[0087] When the MBR content remains unchanged, the QCM test results of the macromolecular initiator with DMA feed composition of 5%, 15%, 30%, and 45% on three different substrates are as follows: Figure 4As shown, in the QCM test graph, the X-axis represents time, and the Y-axis represents the degree of decrease in the third-order vibration frequency of the QCM chip during the flow of the solution; the greater the frequency decrease on the Y-axis, the better the adhesion of the macromolecular initiator on the substrate; it can be seen from the figure that the three different substrates show the same trend. With the increase of DMA feed composition, the adhesion of the macromolecular initiator on the three substrates becomes better. This is because the catechol group on the DMA component plays a decisive role in the adhesion. When the DMA component content increases, the adhesion of the macromolecular initiator on the substrate also increases.

[0088] like Figure 5 As shown in the figure, when the MBR content remains unchanged, when the DMA feed composition is 30%, the Y-axis frequency decreases the least and the anti-protein adhesion performance is the best, and when the DMA feed composition is 5%, the anti-protein adhesion performance is the worst; when the MBR content remains unchanged, as the DMA feed composition increases, the MPC content decreases accordingly. Although the macromolecular initiator can adhere to the substrate better, the reduction of the MPC component will also cause the macromolecular initiator's anti-nonspecific adhesion performance to decrease. There is an antagonistic effect between substrate adhesion and anti-nonspecific adhesion, and the changes in different components may affect the final anti-nonspecific adhesion performance.

[0089] Example 2

[0090] A method for preparing a macromolecular initiator, the specific steps are as follows:

[0091] (1) Preparation of raw materials:

[0092] The thermal initiator is azobisisoheptanonitrile;

[0093] The mixed solvent was dimethylformamide / methanol in a volume ratio of 3:1;

[0094] Monomer I: Chemical structure is

[0095] Monomer II: Chemical structure is

[0096] Monomer III: Chemical structure is

[0097] (2) adding a thermal initiator, monomer I, monomer II and monomer III into a mixed solvent, reacting at 10° C. for 5 h under N2 atmosphere protection, dialyzing the product after the reaction, and freeze-drying it at -40° C. for 48 h to obtain a macromolecular initiator;

[0098] Wherein, based on the total amount of monomer I, monomer II and monomer III, the molar percentage of monomer I is 20%, the molar percentage of monomer II is 15%, and the molar percentage of monomer III is 65%; the molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.01; and the total concentration of monomer I, monomer II and monomer III after being dissolved in a mixed solvent is 100 mg / mL.

[0099] The chemical structure of the macroinitiator is:

[0100] Example 3

[0101] A method for preparing a macromolecular initiator, the specific steps are as follows:

[0102] (1) Preparation of raw materials:

[0103] The thermal initiator was dimethyl azobisisobutyrate;

[0104] The mixed solvent was dimethyl sulfoxide / water in a volume ratio of 2:1;

[0105] Monomer I: Chemical structure is

[0106] Monomer II: Chemical structure is

[0107] Monomer III: Chemical structure is

[0108] (2) adding a thermal initiator, monomer I, monomer II and monomer III into a mixed solvent, reacting at 100° C. for 0.1 h under N2 atmosphere protection, dialyzing the product after the reaction, and freeze-drying it at -40° C. for 48 h to obtain a macromolecular initiator;

[0109] Wherein, based on the total amount of monomer I, monomer II and monomer III, the molar percentage of monomer I is 15%, the molar percentage of monomer II is 20%, and the molar percentage of monomer III is 65%; the molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.001; the total concentration of monomer I, monomer II and monomer III after being dissolved in a mixed solvent is 200 mg / mL.

[0110] The chemical structure of the macroinitiator is:

[0111] Example 4

[0112] A method for preparing a macromolecular initiator, the specific steps are as follows:

[0113] (1) Preparation of raw materials:

[0114] The thermal initiator is azobisisobutylamidine hydrochloride;

[0115] The mixed solvent was dimethyl sulfoxide / methanol in a volume ratio of 1:1;

[0116] Monomer I: Chemical structure is

[0117] Monomer II: Chemical structure is

[0118] Monomer III: Chemical structure is

[0119] (2) adding a thermal initiator, monomer I, monomer II and monomer III into a mixed solvent, reacting at 50° C. for 4 h under N2 atmosphere protection, dialyzing the product after the reaction, and freeze-drying it at -40° C. for 48 h to obtain a macromolecular initiator;

[0120] Wherein, based on the total amount of monomer I, monomer II and monomer III, the molar percentage of monomer I is 30%, the molar percentage of monomer II is 15%, and the molar percentage of monomer III is 55%; the molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.1; and the total concentration of monomer I, monomer II and monomer III after being dissolved in a mixed solvent is 300 mg / mL.

[0121] The chemical structure of the macroinitiator is:

[0122] Example 5

[0123] A method for preparing a macromolecular initiator, the specific steps are as follows:

[0124] (1) Preparation of raw materials:

[0125] The thermal initiator is azobisisoheptanenitrile and dimethyl azobisisobutyrate in a mass ratio of 1:1;

[0126] The mixed solvent was dimethylformamide / water in a volume ratio of 4:1;

[0127] Monomer I: Chemical structure is

[0128] Monomer II: Chemical structure is

[0129] Monomer III: Chemical structure is

[0130] (2) adding a thermal initiator, monomer I, monomer II and monomer III into a mixed solvent, reacting at 80° C. for 1 h under N2 atmosphere protection, dialyzing the product after the reaction, and freeze-drying it at -40° C. for 48 h to obtain a macromolecular initiator;

[0131] Wherein, based on the total amount of monomer I, monomer II and monomer III, the molar percentage of monomer I is 10%, the molar percentage of monomer II is 10%, and the molar percentage of monomer III is 80%; the molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.005; the total concentration of monomer I, monomer II and monomer III after being dissolved in a mixed solvent is 400 mg / mL.

[0132] The chemical structure of the macroinitiator is:

[0133] Example 6

[0134] A method for preparing a macromolecular initiator, the specific steps are as follows:

[0135] (1) Preparation of raw materials:

[0136] The thermal initiator is dimethyl azobisisobutyrate and azobisisobutylamidine hydrochloride in a mass ratio of 1:1;

[0137] The mixed solvent was dimethylformamide / methanol in a volume ratio of 5:1;

[0138] Monomer I: Chemical structure is

[0139] Monomer II: Chemical structure is

[0140] Monomer III; chemical structure is

[0141] (2) adding a thermal initiator, monomer I, monomer II and monomer III into a mixed solvent, reacting at 90° C. for 1.5 h under N2 atmosphere protection, dialyzing the product after the reaction, and freeze-drying it at -40° C. for 48 h to obtain a macromolecular initiator;

[0142] Wherein, based on the total amount of monomer I, monomer II and monomer III, the molar percentage of monomer I is 40%, the molar percentage of monomer II is 20%, and the molar percentage of monomer III is 40%; the molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.05; the total concentration of monomer I, monomer II and monomer III after being dissolved in a mixed solvent is 150 mg / mL.

[0143] The chemical structure of the macroinitiator is:

[0144] Example 7

[0145] A method for preparing a miniaturized multi-parameter water quality sensor chip with anti-fouling function, such as Figure 3 As shown, the specific steps are as follows:

[0146] (1) Preparation of raw materials:

[0147] Macromolecular initiator solution: The macromolecular initiator of Example 1 was dissolved in an acetate buffer solution with a pH of 3.7 to obtain a macromolecular initiator solution with a concentration of 0.5 mg / mL;

[0148] The micronized multi-parameter water quality sensor chip has a surface substrate including an electrode substrate made of gold, a packaging layer substrate made of parylene, and a sensitive layer substrate made of polyvinyl chloride (PVC); the micronized multi-parameter water quality sensor chip can detect the following parameters:

[0149] pH detection: The all-solid-state ion selective electrode method was used to modify a layer of conductive polymer PEDOT:PSS on the surface of the gold substrate as a transducer layer to achieve ion-electron signal transduction. A layer of ion selective membrane (PVC membrane) was modified on the surface of the transducer layer, and hydrogen ion carrier I was used as an ion carrier to achieve H + Selective detection of concentration;

[0150] Ammonia nitrogen detection: First, a layer of conductive polymer PEDOT:PSS is modified on the gold substrate as a transducer layer, and then a layer of ammonium ion selective membrane (PVC membrane) is modified as a sensitive layer, and the ammonium ion carrier in the membrane is used to achieve selective detection of ammonium ions;

[0151] Dissolved oxygen detection: The electrode consists of three parts: working electrode, reference electrode and counter electrode. Both the working electrode and the counter electrode are gold electrodes, and the reference electrode is a solid-state Ag / AgCl reference electrode modified with PVB. The principle of electrochemical detection is that the oxygen dissolved in water undergoes a reduction reaction at the working electrode and an oxidation reaction at the counter electrode. The linear relationship between oxygen concentration and current is used, and the dissolved oxygen content is detected by detecting the current using a three-electrode system;

[0152] Conductivity detection: The design of the annular four-electrode structure is adopted. The four-electrode structure consists of two voltage electrodes and two current electrodes. All four electrodes are gold electrodes. An alternating current is applied between the current electrodes as an excitation signal. By detecting the induced voltage between the voltage electrodes, the conductivity of the solution can be calculated, and then the conductivity of the solution to be tested can be calculated;

[0153] Temperature detection: Gold is selected as the material of RTD temperature sensor. The principle of detecting temperature change is to detect temperature change by using the property that the resistance of metal conductor increases with the increase of temperature within a certain temperature range.

[0154] (2) immersing the miniaturized multi-parameter water quality sensor chip in a macromolecular initiator solution for 2 minutes, and simultaneously and autonomously adhering and modifying a layer of macromolecular initiator on a variety of substrates on the surface of the miniaturized multi-parameter water quality sensor chip to complete the macromolecular initiator modification;

[0155] (3) Using copper bromide as a catalyst, tri(2-pyridylmethyl)amine as a ligand, and a reaction solvent of a mixed solvent of DMSO:H2O (volume ratio 1:1), the monomer concentration was controlled to be 800mM, the macromolecular initiator concentration was 40mM, the copper bromide concentration was 2mM, and the tri(2-pyridylmethyl)amine concentration was 4mM. The zwitterionic polymer chain was grafted onto the macromolecular initiator by atom transfer radical polymerization (ATRP) at 75°C. The reaction was carried out for 3h to form a zwitterionic functional antifouling coating on the substrate of the miniaturized multi-parameter water quality sensor chip. After rinsing with deionized water and drying with N2, a miniaturized multi-parameter water quality sensor chip with antifouling function was prepared.

[0156] The surface substrate of the miniaturized multi-parameter water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is:

[0157] like Figure 7 As shown in the figure, the contact angles of the substrates were significantly reduced after modification with the macromolecular initiator, and the contact angles of all substrates were further reduced after ATRP polymerization was initiated on the surface, proving that the MPC polymer chains were successfully grafted onto the surface, promoting the hydrophilicity of the substrate surface.

[0158] The unmodified, macromolecular initiator-modified, and zwitterion-functionalized antifouling coating-modified multi-parameter water quality sensor chips were immersed in 1 mg / mL fluorescent protein (FITC-BSA)-PBS buffer solution for 30 min, then rinsed with deionized water and observed under a fluorescence microscope. The green fluorescence intensity was used to determine the amount of protein adhesion. Figure 8 As shown, the green fluorescence intensity of the unmodified water quality sensor chip surface is the strongest, the green fluorescence intensity of the water quality sensor chip surface modified with the macromolecular initiator is significantly weakened, and there is no obvious fluorescence phenomenon on the water quality sensor chip surface modified with the zwitterion functionalized antifouling coating, indicating that the surface of the water quality sensor chip modified with the zwitterion functionalized antifouling coating has excellent anti-nonspecific adhesion performance.

[0159] like Fig. 9As shown, the detection sensitivity of the pH sensor modified with the zwitterion functionalized antifouling coating decreased by only 1.6 mV / dec compared with the pH sensor not modified with the zwitterion functionalized antifouling coating; the detection sensitivity of the ammonia nitrogen sensor modified with the zwitterion functionalized antifouling coating decreased by 1.38 mV / dec compared with the ammonia nitrogen sensor not modified with the zwitterion functionalized antifouling coating; the detection sensitivity of the dissolved oxygen sensor modified with the zwitterion functionalized antifouling coating decreased by 0.23 μA / (mg / L) compared with the dissolved oxygen sensor not modified with the zwitterion functionalized antifouling coating; the conductivity cell coefficient K of the conductivity sensor modified with the zwitterion functionalized antifouling coating became 0.75, which was only 0.03 lower than that of the conductivity sensor not modified with the zwitterion functionalized antifouling coating; the above results show that the modification of the zwitterion functionalized antifouling coating has little effect on the detection performance of each sensor, because the zwitterion polymer has excellent hydrophilicity and permeability and will not have a significant effect on surface mass transfer.

[0160] like Fig.11 As shown in a) and b), the sensitivity of the pH sensor modified with the zwitterion functionalized antifouling coating decreased by only 14.5% after being tested in pond water for 21 days, while the sensitivity of the sensor not modified with the zwitterion functionalized antifouling coating decreased by 31.2% after being immersed in pond water for 21 days; and after being immersed in a PBS solution containing 1 mg / mL BSA (i.e., BSA solution) for 21 days, the sensitivity of the pH sensor modified with the zwitterion functionalized antifouling coating decreased by 21%, and the sensitivity of the unmodified pH sensor decreased from the initial 50.2 mV / dec to 21.55 mV / dec due to the influence of protein adhesion, which decreased by 57%; Fig.11 As shown in c) and d), the sensitivity of the ammonia nitrogen sensor modified with zwitterion functional antifouling coating decreased by 11.2% and 17.4% respectively after being immersed in pond water and BSA solution for 21 days, while the sensitivity of the ammonia nitrogen sensor not modified with zwitterion functional antifouling coating decreased by 36.9% and 48.8% respectively after being immersed in pond water and BSA solution for 21 days; Fig.11 As shown in Figures e) and f), the sensitivity of the unmodified dissolved oxygen sensor after being immersed in pond water and BSA solution for 21 days decreased by 42.8% and 44.6%, respectively, indicating that the adhesion of pollutants such as proteins on the electrode has a great influence on the sensor performance. After being modified with the zwitterion functionalized antifouling coating, the sensitivity of the dissolved oxygen sensor after being immersed in the two solutions for 21 days decreased by 20.6% and 22.1%, respectively, showing good anti-nonspecific adhesion performance; Fig.11As shown in g) and h), the conductivity cell coefficient K of the unmodified conductivity sensor decreased by 17.6% after being immersed in pond water for 21 days, and the K value decreased by 26.4% after being immersed in BSA solution for 21 days. After being modified with the zwitterion functionalized antifouling coating, the conductivity cell coefficient K of the conductivity sensor decreased by only 8% after being immersed in pond water for 21 days, and the K value decreased by 10.1% after being immersed in BSA solution for 21 days, and the degree of change was lower than that of the unmodified one. The above experimental results show that compared with the unmodified multi-parameter water quality sensor chip, the multi-parameter water quality sensor chip modified with the zwitterion functionalized antifouling coating has good anti-nonspecific adhesion performance, and the sensors of each parameter still maintain good detection performance after 21 days of detection in a complex water environment.

[0161] Using ternary copolymer (DMA:MPC:MBR=30:60:10wt%) as macromolecular initiator, MPC as monomer, CuBr2 as catalyst, TPMA as ligand, and reaction solvent as mixed solvent of DMSO:H2O (volume ratio 1:1), the reaction time of preparing zwitterionic functional antifouling coating was controlled to be 0.5h, 1h, 2h, and 3h respectively, and the zwitterionic functional antifouling coating prepared with different reaction time was grafted on the surface of gold substrate. The adhesion of gold surface and bovine serum albumin (BSA) after different ATRP polymerization time was tested by QCM, and the results are as follows Fig.10 As shown in a, when the reaction time of ATRP polymerization increases from 0.5h to 3h, the frequency decreases from 5Hz to 1Hz in the QCM test; when the reaction time increases from 2h to 3h, the frequency does not change much, indicating that after 3h of ATRP reaction, the modified substrate surface already has excellent anti-nonspecific adhesion performance, so 3h is selected as the ATRP polymerization reaction time. In order to compare the anti-nonspecific adhesion performance of each material surface before and after ATRP polymerization, the QCM experiment was used to evaluate the protein adhesion behavior of gold, Parylene and PVC substrates modified with macromolecular initiators and gold, Parylene and PVC substrates after 3h ATRP grafting polymerization; the results are shown in Fig.10 As shown in b, c, and d, the surface anti-protein adhesion ability of the three substrates was greatly improved after ATRP grafting polymerization, confirming the excellent anti-nonspecific adhesion performance of the zwitterionic functionalized antifouling coating.

[0162] Example 8

[0163] A method for preparing a miniaturized multi-parameter water quality sensor chip with anti-fouling function, the specific steps are as follows:

[0164] (1) Preparation of raw materials:

[0165] Macromolecular initiator solution: The macromolecular initiator of Example 2 was dissolved in an acetate buffer solution with a pH of 3.7 to obtain a macromolecular initiator solution with a concentration of 1 mg / mL;

[0166] The micronized multi-parameter water quality sensor chip has a surface substrate including an electrode substrate made of platinum, a packaging layer substrate made of polydimethylsiloxane, and a sensitive layer substrate made of iridium oxide nanoparticles; the micronized multi-parameter water quality sensor chip can detect the following parameters:

[0167] pH detection: A layer of iridium oxide nanoparticles is modified on the surface of the platinum electrode to detect H + Selective detection of concentration;

[0168] Ammonia nitrogen detection: This is achieved by modifying the surface of a platinum electrode with a layer of iridium oxide nanoparticles that selectively detect ammonia nitrogen;

[0169] Dissolved oxygen detection: The electrode consists of three parts: working electrode, reference electrode and counter electrode. Both the working electrode and the counter electrode are platinum electrodes, and the reference electrode is a PVB-modified all-solid-state Ag / AgCl reference electrode. The principle of electrochemical detection is that the oxygen dissolved in water undergoes a reduction reaction at the working electrode and an oxidation reaction at the counter electrode. The linear relationship between oxygen concentration and current is used, and the dissolved oxygen content is detected by detecting the current using a three-electrode system;

[0170] Conductivity detection: The design of the annular four-electrode structure is adopted. The four-electrode structure consists of two voltage electrodes and two current electrodes. All four electrodes are platinum electrodes. An alternating current is applied between the current electrodes as an excitation signal. By detecting the induced voltage between the voltage electrodes, the conductivity of the solution can be calculated, and then the conductivity of the solution to be tested can be calculated;

[0171] Temperature detection: Platinum is selected as the material of RTD temperature sensor. The principle of detecting temperature change is to detect temperature change by using the property that the resistance of metal conductor platinum increases with the increase of temperature within a certain temperature range.

[0172] (2) The miniaturized multi-parameter water quality sensor chip is immersed in a macromolecular initiator solution for 3 minutes, and a layer of macromolecular initiator is self-adhered and modified on various substrates on the surface of the miniaturized multi-parameter water quality sensor chip at the same time, thereby completing the macromolecular initiator modification;

[0173] (3) Using cuprous bromide as a catalyst, tri(2-pyridylmethyl)amine as a ligand, and a reaction solvent of a mixed solvent of DMSO:H2O (volume ratio 1:1), the monomer concentration was controlled to be 1000mM, the macromolecular initiator concentration was 80mM, the cuprous bromide concentration was 5mM, and the tri(2-pyridylmethyl)amine concentration was 15mM. The zwitterionic polymer chain was grafted onto the macromolecular initiator by atom transfer radical polymerization (ATRP) at 10°C. The reaction was carried out for 5h to form a zwitterionic functional antifouling coating on the substrate of the miniaturized multi-parameter water quality sensor chip. After rinsing with deionized water and drying with N2, a miniaturized multi-parameter water quality sensor chip with antifouling function was prepared.

[0174] The surface substrate of the miniaturized multi-parameter water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is:

[0175] After the antifouling coating was modified on the surface of the miniaturized multi-parameter water quality sensor chip, the contact angle of the platinum substrate decreased to 8°, the contact angle of the polydimethylsiloxane substrate decreased to 10.5°, and the contact angle of the iridium oxide nanoparticle substrate decreased to 10.3°. In the green fluorescence experiment, no obvious fluorescence phenomenon was observed on the surface of the miniaturized multi-parameter water quality sensor chip modified with the zwitterion functional antifouling coating, indicating that the zwitterion functional antifouling coating was successfully modified on the surface of the miniaturized multi-parameter water quality sensor chip. The adhesion of the miniaturized multi-parameter water quality sensor chip modified with the zwitterion functional antifouling coating to bovine serum albumin (BSA) was tested by QCM. The results showed that the frequency of the platinum substrate decreased by 0.8Hz, the frequency of the polydimethylsiloxane substrate decreased by 0.85Hz, and the frequency of the iridium oxide nanoparticle substrate decreased by 0.84Hz after modification, indicating that the miniaturized multi-parameter water quality sensor chip has good anti-nonspecific adhesion performance. The sensor chip integrating various parameters still maintains good detection performance after 30 days of detection in BSA solution.

[0176] Example 9

[0177] A method for preparing a miniaturized multi-parameter water quality sensor chip with anti-fouling function, the specific steps are as follows:

[0178] (1) Preparation of raw materials:

[0179] Macromolecular initiator solution: The macromolecular initiator of Example 3 was dissolved in an acetate buffer solution at a pH of 4 to obtain a macromolecular initiator solution with a concentration of 2 mg / mL;

[0180] The miniaturized multi-parameter water quality sensor chip has a surface substrate including an electrode substrate made of graphene, an encapsulation layer substrate made of polyurethane, and a sensitive layer substrate made of carbon nanotubes; the miniaturized multi-parameter water quality sensor chip can detect the following parameters:

[0181] pH detection: Use the change of carbon nanotube conductivity to indirectly detect the change of pH value in water;

[0182] Conductivity detection: The design of a ring-shaped four-electrode structure is adopted. The four-electrode structure consists of two voltage electrodes and two current electrodes. All four electrodes are graphene electrodes. An alternating current is applied between the current electrodes as an excitation signal. By detecting the induced voltage between the voltage electrodes, the conductivity of the solution can be calculated, and then the conductivity of the solution to be tested can be calculated;

[0183] Mercury ion detection: Carbon nanotubes can interact with heavy metal ions in water through adsorption or surface reaction, thereby changing their electron transport properties for detection;

[0184] (2) The miniaturized multi-parameter water quality sensor chip is immersed in a macromolecular initiator solution for 4 minutes, and a layer of macromolecular initiator is self-adhered and modified on various substrates on the surface of the miniaturized multi-parameter water quality sensor chip at the same time, thereby completing the macromolecular initiator modification;

[0185] (3) Using cuprous bromide as a catalyst, tri(2-methylaminoethyl)amine as a ligand, and dimethyl sulfoxide (DMSO):H2O (volume ratio 1:1) as the reaction solvent, the monomer concentration was controlled to be 500 mM, the macromolecular initiator concentration was 20 mM, the cuprous bromide concentration was 3 mM, and the tri(2-methylaminoethyl)amine concentration was 8 mM. The zwitterionic polymer chain was grafted onto the macromolecular initiator by atomic free radical polymerization at 100 °C. The reaction was carried out for 3 hours to form a zwitterionic functional antifouling coating on the substrate of the miniaturized multi-parameter water quality sensor chip. After rinsing with deionized water and drying with N2, a miniaturized multi-parameter water quality sensor chip with antifouling function was prepared.

[0186] The surface substrate of the miniaturized multi-parameter water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is:

[0187] After the antifouling coating was modified on the surface of the miniaturized multi-parameter water quality sensor chip, the contact angle of the graphene substrate was reduced to 12°, the contact angle of the polyurethane substrate was reduced to 12.5°, and the contact angle of the carbon nanotube substrate was reduced to 12.3°. No obvious fluorescence phenomenon was observed in the green fluorescence experiment, indicating that the zwitterion functional antifouling coating was successfully modified on the surface of the miniaturized multi-parameter water quality sensor chip. The adhesion of the miniaturized multi-parameter water quality sensor chip modified with the zwitterion functional antifouling coating to bovine serum albumin (BSA) was tested by QCM. The results showed that the frequency of the modified graphene substrate decreased by 1.6Hz, the frequency of the polyurethane substrate decreased by 2Hz, and the frequency of the carbon nanotube substrate decreased by 1.5Hz, indicating that the miniaturized multi-parameter water quality sensor chip has good anti-nonspecific adhesion performance. The sensor chip integrating various parameters still maintains good detection performance after 20 days of detection in BSA solution.

[0188] Example 10

[0189] A method for preparing a miniaturized water quality sensor chip with anti-fouling function, the specific steps are as follows:

[0190] (1) Preparation of raw materials:

[0191] Macromolecular initiator solution: The macromolecular initiator of Example 4 was dissolved in an acetate buffer solution with a pH of 5.5 to obtain a macromolecular initiator solution with a concentration of 3 mg / mL;

[0192] The miniaturized multi-parameter water quality sensor chip has a surface substrate including an electrode substrate made of carbon nanotubes, a packaging layer substrate made of polyimide, and a sensitive layer substrate made of palladium oxide nanoparticles; the miniaturized multi-parameter water quality sensor chip can detect the following parameters:

[0193] pH detection: A layer of palladium oxide nanoparticles is modified on the surface of the carbon nanotube electrode to detect H + Selective detection of concentration;

[0194] Ammonia nitrogen detection: This is achieved by modifying the surface of the carbon nanotube electrode with a layer of palladium oxide nanoparticles that selectively detect ammonia nitrogen;

[0195] Conductivity detection: The design of a ring-shaped four-electrode structure is adopted. The four-electrode structure consists of two voltage electrodes and two current electrodes. All four electrodes are carbon nanotube electrodes. An alternating current is applied between the current electrodes as an excitation signal. By detecting the induced voltage between the voltage electrodes, the conductivity of the solution can be calculated, and then the conductivity of the solution to be tested can be calculated;

[0196] Chromium ion detection: palladium oxide nanoparticles can interact with heavy metal ions in water through adsorption or surface reaction, thereby changing their surface plasmon resonance characteristics or fluorescence properties for detection;

[0197] (2) immersing the miniaturized multi-parameter water quality sensor chip in a macromolecular initiator solution for 5 minutes, and simultaneously and autonomously adhering and modifying a layer of macromolecular initiator on a variety of substrates on the surface of the miniaturized multi-parameter water quality sensor chip to complete the macromolecular initiator modification;

[0198] (3) Using cuprous bromide as a catalyst and bipyridine as a ligand, the reaction solvent is a mixed solvent of dimethyl sulfoxide (DMSO):H2O (volume ratio 2:1), the monomer concentration is controlled to be 900mM, the macromolecular initiator concentration is 50mM, the cuprous bromide concentration is 3mM, and the bipyridine concentration is 10mM. The zwitterionic polymer chain is grafted onto the macromolecular initiator by atom transfer radical polymerization at 50°C. The reaction is carried out for 4h to form a zwitterionic functional antifouling coating on the substrate of the miniaturized multi-parameter water quality sensor chip. After rinsing with deionized water and drying with N2, a miniaturized multi-parameter water quality sensor chip with antifouling function is prepared.

[0199] The surface substrate of the miniaturized multi-parameter water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is:

[0200] After the surface of the miniaturized multi-parameter water quality sensor chip was modified with zwitterion functional antifouling coating, the contact angle of the carbon nanotube substrate was reduced to 9.5°, the contact angle of the polyimide substrate was reduced to 10°, and the contact angle of the palladium oxide nanoparticle substrate was reduced to 10.5°. No obvious fluorescence phenomenon was observed in the green fluorescence experiment, indicating that the zwitterion functional antifouling coating was successfully modified on the surface of the miniaturized multi-parameter water quality sensor chip. The adhesion of the miniaturized multi-parameter water quality sensor chip modified with zwitterion functional antifouling coating to bovine serum albumin (BSA) was tested by QCM. The results showed that the frequency of the modified carbon nanotube substrate decreased by 0.75Hz, the frequency of the polyimide substrate decreased by 0.9Hz, and the frequency of the palladium oxide nanoparticle substrate decreased by 0.88Hz, indicating that the miniaturized multi-parameter water quality sensor chip has good anti-nonspecific adhesion performance. The sensor chip integrating various parameters still maintains good detection performance after 25 days of detection in BSA solution.

[0201] Embodiment 11

[0202] A method for preparing a miniaturized water quality sensor chip with anti-fouling function, the specific steps are as follows:

[0203] (1) Preparation of raw materials:

[0204] Macromolecular initiator solution: The macromolecular initiator of Example 5 was dissolved in an acetate buffer solution with a pH of 3.7 to obtain a macromolecular initiator solution with a concentration of 4 mg / mL;

[0205] The miniaturized multi-parameter water quality sensor chip has a surface substrate including an electrode substrate made of gold nanowires, a packaging layer substrate made of polyparaxylene, and a sensitive layer substrate made of carbon nanotubes. The miniaturized multi-parameter water quality sensor chip can detect the following parameters:

[0206] Dissolved oxygen detection: The electrode consists of three parts: working electrode, reference electrode and counter electrode. Both the working electrode and the counter electrode are gold nanowire electrodes, and the reference electrode is a PVB-modified all-solid-state Ag / AgCl reference electrode.

[0207] Conductivity detection: The design of a ring-shaped four-electrode structure is adopted. The four-electrode structure consists of two voltage electrodes and two current electrodes. All four electrodes are gold nanowire electrodes. An alternating current is applied between the current electrodes as an excitation signal. By detecting the induced voltage between the voltage electrodes, the conductivity of the solution can be calculated, and then the conductivity of the solution to be tested can be calculated;

[0208] Mercury ion detection: Carbon nanotubes can interact with heavy metal ions in water through adsorption or surface reaction, thereby changing their electron transport properties for detection;

[0209] Sodium ion detection: Carbon nanotubes can respond to changes in ion concentration by interacting with ions in water, thereby affecting electronic conductivity for detection;

[0210] (2) The miniaturized multi-parameter water quality sensor chip is immersed in a macromolecular initiator solution for 3 minutes, and a layer of macromolecular initiator is self-adhered and modified on various substrates on the surface of the miniaturized multi-parameter water quality sensor chip at the same time, thereby completing the macromolecular initiator modification;

[0211] (3) Using cuprous bromide as a catalyst, tri(2-methylaminoethyl)amine as a ligand, and the reaction solvent being DMSO:H2O (volume ratio 2:1), the monomer concentration was controlled to be 500 mM, the macromolecular initiator concentration was 20 mM, the cuprous bromide concentration was 1 mM, and the tri(2-methylaminoethyl)amine concentration was 2 mM. The zwitterionic polymer chain was grafted onto the macromolecular initiator by atom transfer radical polymerization at 80°C. The reaction was performed for 1 hour to form a zwitterionic functional antifouling coating on the substrate of the miniaturized multi-parameter water quality sensor chip. After rinsing with deionized water and drying with N2, a miniaturized multi-parameter water quality sensor chip with antifouling function was prepared.

[0212] The surface substrate of the miniaturized multi-parameter water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is:

[0213] After the antifouling coating was modified on the surface of the miniaturized multi-parameter water quality sensor chip, the contact angle of the gold nanowire substrate was reduced to 20.5°, the contact angle of the polyparaxylene substrate was reduced to 19°, and the contact angle of the carbon nanotube substrate was reduced to 20°. No obvious fluorescence phenomenon was observed in the green fluorescence experiment, indicating that the zwitterion functional antifouling coating was successfully modified on the surface of the miniaturized multi-parameter water quality sensor chip. The adhesion of the miniaturized multi-parameter water quality sensor chip modified with the zwitterion functional antifouling coating to bovine serum albumin (BSA) was tested by QCM. The results showed that the frequency of the gold nanowire substrate decreased by 5Hz, the frequency of the polyparaxylene substrate decreased by 4.5Hz, and the frequency of the carbon nanotube substrate decreased by 5.2Hz after modification, indicating that the miniaturized multi-parameter water quality sensor chip has good anti-nonspecific adhesion performance. The sensor chip integrating various parameters still maintains good detection performance after 15 days of detection in BSA solution.

[0214] Example 12

[0215] A method for preparing a miniaturized multi-parameter water quality sensor chip with anti-fouling function, the specific steps are as follows:

[0216] (1) Preparation of raw materials:

[0217] Macromolecular initiator solution: the macromolecular initiator of Example 6 was dissolved in an acetate buffer solution at a pH of 4 to obtain a macromolecular initiator solution with a concentration of 5 mg / mL;

[0218] A miniaturized multi-parameter water quality sensor chip, the substrate on the surface of which includes an electrode substrate made of poly (3,4-ethylenedioxythiophene), a packaging layer substrate made of polydimethylsiloxane, and a sensitive layer substrate made of graphene; the miniaturized multi-parameter water quality sensor chip can detect the following parameters:

[0219] Dissolved oxygen detection: Use the change of carbon nanotube conductivity to indirectly detect the change of dissolved oxygen value in water;

[0220] Conductivity detection: The design of a ring-shaped four-electrode structure is adopted. The four-electrode structure consists of two voltage electrodes and two current electrodes. All four electrodes are poly-3,4-ethylenedioxythiophene electrodes. An alternating current is applied between the current electrodes as an excitation signal. By detecting the induced voltage between the voltage electrodes, the conductivity of the solution can be calculated, and then the conductivity of the solution to be tested can be calculated;

[0221] Chromium ion detection: Graphene can interact with heavy metal ions in water through adsorption or surface reaction, thereby changing its electron transport properties for detection;

[0222] Temperature detection: Poly(3,4-ethylenedioxythiophene) is selected as the RTD temperature sensor material. The principle of detecting temperature changes is to use the characteristic that the resistance of the conductive polymer poly(3,4-ethylenedioxythiophene) increases with the increase of temperature within a certain temperature range to detect temperature changes;

[0223] (2) immersing the miniaturized multi-parameter water quality sensor chip in a macromolecular initiator solution for 5 minutes, and simultaneously and autonomously adhering and modifying a layer of macromolecular initiator on a variety of substrates on the surface of the miniaturized multi-parameter water quality sensor chip to complete the macromolecular initiator modification;

[0224] (3) Using cuprous chloride as a catalyst and bipyridine as a ligand, the reaction solvent is a mixed solvent of dimethylformamide (DMF):H2O (volume ratio 1:1), the monomer concentration is controlled to be 600mM, the macromolecular initiator concentration is 20mM, the cuprous chloride concentration is 2mM, and the bipyridine concentration is 5mM. The zwitterionic polymer chain is grafted onto the macromolecular initiator by atom transfer radical polymerization at 90°C. The reaction is carried out for 1.5h to form a zwitterionic functional antifouling coating on the substrate of the miniaturized multi-parameter water quality sensor chip. After rinsing with deionized water and drying with N2, a miniaturized multi-parameter water quality sensor chip with antifouling function is prepared.

[0225] The surface substrate of the miniaturized multi-parameter water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is:

[0226] After the antifouling coating was modified on the surface of the miniaturized multi-parameter water quality sensor chip, the contact angle of the poly(3,4-ethylenedioxythiophene) substrate was reduced to 18°, the contact angle of the poly(dimethylsiloxane) substrate was reduced to 18.5°, and the contact angle of the graphene substrate was reduced to 18.6°. No obvious fluorescence phenomenon was observed in the green fluorescence experiment, indicating that the zwitterion functional antifouling coating was successfully modified on the surface of the miniaturized multi-parameter water quality sensor chip. The adhesion of the miniaturized multi-parameter water quality sensor chip modified with the zwitterion functional antifouling coating to bovine serum albumin (BSA) was tested by QCM. The results showed that the frequency of the poly(3,4-ethylenedioxythiophene) substrate decreased by 4Hz, the frequency of the poly(dimethylsiloxane) substrate decreased by 4.7Hz, and the frequency of the graphene substrate decreased by 4.5Hz after modification, indicating that the miniaturized multi-parameter water quality sensor chip has good anti-nonspecific adhesion performance. The sensor chip integrating various parameters still maintains good detection performance after 18 days of detection in BSA solution.

Claims

1. A method for preparing a miniaturized water quality sensor chip with anti-fouling function, characterized in that: Firstly, the miniaturized water quality sensor chip is immersed in a macromolecular initiator solution, and the macromolecular initiator spontaneously adheres to various substrates on the surface of the miniaturized water quality sensor chip, thereby modifying a layer of macromolecular initiator on the substrate, and then the zwitterionic functionalized polymer is polymerized and grafted on the substrate after the modification of the macromolecular initiator to form a zwitterionic functionalized antifouling coating, thereby obtaining a miniaturized water quality sensor chip with antifouling function; The macromolecular initiator solution is obtained by dissolving the macromolecular initiator in a buffer solution having a pH of 3.7 to 5.5; The time for the macromolecular initiator to spontaneously adhere and modify is 1 to 5 minutes; The chemical structure of the macroinitiator is shown in formula (A); Where: m, n, z are positive integers, and 1≤m≤50000, 1≤n≤50000, 1≤z≤50000, m / (m+n+z)=0.1%~99.9%, n / (m+n+z)=0.1%~99.9%, z / (m+n+z)=0.1%~99.9%; R1, R2, and R3 are independently any one of -H, -CH3, -NH2, -OH, -COOH, and --SH; R4, R5, and R7 are independently -H, --(CH) d Any one of CH3, wherein d is a positive integer and 0≤d≤8; R6-X is -X, Any one of, wherein X is any one of Br, Cl, I; R8 is Any one of , where c is a positive integer and 1≤c≤30; L1 and L2 are independently -CO-O-(CH2) a -、-O-CO-(CH2) a -、-NH-CO-(CH2) a -、-CO-NH-CO-(CH2) a -、-CO-NH-(CH2) a -O-CO-, -NH-CO-(CH2) a -O-CO-, -CO-O-(CH2) a -O-CO-, -O-CO-(CH2) a -O-CO-, -CO-O-(CH2) a -NH-CO-, -O-CO-(CH2) a -NH-CO-, -CO-NH-(CH2) a -NH-CO-, -NH-CO-(CH2) a Any one of -NH-CO-, wherein a is a positive integer, and 0≤a≤8.

2. The method for preparing a miniaturized water quality sensor chip with anti-fouling function according to claim 1, characterized in that: The substrate comprises an electrode substrate, a packaging layer substrate and a sensitive layer substrate; The electrode substrate material is gold, platinum, graphene, carbon nanotubes, metal nanowires or conductive polymers; The base material of the encapsulation layer is polyparaxylene, polydimethylsiloxane, polyurethane or polyimide; The substrate material of the sensitive layer is polyvinyl chloride, metal nanoparticles, carbon nanotubes, graphene or conductive polymer.

3. The method for preparing a miniaturized water quality sensor chip with anti-fouling function according to claim 1 or 2, characterized in that: The specific preparation steps of the miniaturized water quality sensor chip with anti-fouling function are as follows: (1) first dissolving the macromolecular initiator in a buffer solution with a pH of 3.7 to 5.5 to obtain a macromolecular initiator solution with a concentration of 0.1 to 5 mg / mL, and then immersing the miniaturized water quality sensor chip in the macromolecular initiator solution for 1 to 5 minutes to complete the macromolecular initiator modification; (2) The zwitterionic polymer chain was grafted onto the macromolecular initiator by atom transfer radical polymerization to form a zwitterionic functional antifouling coating on the surface substrate of the miniaturized water quality sensor chip. After rinsing with deionized water and drying with nitrogen, a miniaturized water quality sensor chip with antifouling function was prepared.

4. The method for preparing a miniaturized water quality sensor chip with anti-fouling function according to claim 3, characterized in that: The buffer solution in step (1) is an acetate buffer solution.

5. The method for preparing a miniaturized water quality sensor chip with anti-fouling function according to claim 3, characterized in that: The process of forming a zwitterion functionalized antifouling coating on the substrate on the surface of the miniaturized water quality sensor chip in step (2) is as follows: adding a catalyst, a ligand, a zwitterion monomer, and a miniaturized water quality sensor chip modified with a macromolecular initiator to a solvent, performing atom transfer radical polymerization under the protection of a N2 atmosphere, and forming a zwitterion functionalized antifouling coating on the substrate on the surface of the miniaturized water quality sensor chip; The molar ratio of the catalyst to the ligand is 1:1-8; the concentration of the zwitterionic monomer after being dissolved in the solvent is 10-5000 mM; the concentration of the macromolecular initiator after being dissolved in the solvent is 1-10 mol% of the concentration of the zwitterionic monomer after being dissolved in the solvent.

6. The method for preparing a miniaturized water quality sensor chip with antifouling function according to claim 5, characterized in that: The temperature of the atom transfer radical polymerization is 10 to 100° C., and the time is more than 1 hour.

7. The method for preparing a miniaturized water quality sensor chip with antifouling function according to claim 1, characterized in that: The preparation process of the macromolecular initiator is as follows: prepare a mixed solvent, add a thermal initiator, monomer I, monomer II and monomer III into the mixed solvent, react under the protection of a N2 atmosphere, and after the reaction is completed, dialyze and freeze-dry the product to obtain the macromolecular initiator; The mixed solvent is dimethylformamide / water, dimethylformamide / methanol, dimethyl sulfoxide / water or dimethyl sulfoxide / methanol; The thermal initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate and azobisisobutylamidine hydrochloride; The chemical structures of monomer I, monomer II and monomer III are shown in formula (B), (C) and (D), respectively; 8. The method for preparing a miniaturized water quality sensor chip with antifouling function according to claim 7, characterized in that: The reaction temperature is 10-100°C, and the reaction time is 0.1-5h.

9. The method for preparing a miniaturized water quality sensor chip with antifouling function according to claim 8, characterized in that: Based on the total amount of monomer I, monomer II, and monomer III, the molar percentage of monomer I is 1% to 50%, the molar percentage of monomer II is 1% to 20%, and the molar percentage of monomer III is 30% to 98%; The molar ratio of the total amount of monomer I, monomer II and monomer III to the thermal initiator is 1:0.001-1; The total concentration of monomer I, monomer II and monomer III after being dissolved in the mixed solvent is 0.1-1000 mg / mL.

10. A miniaturized water quality sensor chip with antifouling function obtained by the method according to any one of claims 1 to 9, characterized in that: The surface substrate of the miniaturized water quality sensor chip with antifouling function has a zwitterion functional antifouling coating, and the chemical structure of the zwitterion functional antifouling coating is: Wherein: y is a positive integer, and 1≤y≤50000.

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