Construction And Performance Of Molecularly Imprinted Biosensors Based On Biomass Carbon And Metal-organic Framework Derivatives

The key part of constructing biosensors is the immobilized bio-sensitive materials as recognition elements(enzymes,antigens,antibodies and other biologically active substances).However,biologically active substances are easily affected by environmental factors such as acidity,alkalinity,and temperature,which leads to a decrease in the stability and sensitivity of the biosensor.Using molecularly imprinted polymers(MIPs)as recognition elements can effectively simulate the specific recognition process of antigen-antibody.Compared with biologically active substances,it has better cheapness and stability.At the same time,the development and application of MIPs have also promoted the diversification of identification components in biosensors,making them more practical.In summary,based on the excellent properties of biomass carbon(BC),metal organic framework(MOF)and metal nanomaterials,two molecularly imprinted biosensors for different analytes have been initially constructed.Used for the detection of nitrofurazone(NFZ)and furosemide in biological fluid environment.Through a series of characterization and electrochemical performance tests,nanomaterials and analytes were studied in detail.Based on experimental research and data analysis,the following results were obtained:1.Zeolite imidazole skeleton material 8(ZIF-8)has high porosity and specific surface area,excellent water stability and is convenient to synthesize.In this study,an original electrochemical imprinting sensor based on the modified glassy carbon electrode(GCE)with C₃N₄ nanosheets and framework ZIF-8 combined with MIP(ZIF-8@MIP)is developed for the sensitive detection of furosemide.MIP was formed by precipitation polymerization of ZIF-8 with furosemide as template and methacrylic acid(MAA)as monomer,and furosemide was detected by differential pulse voltammetry(DPV).Under the optimized conditions,the DPV response of C₃N₄/ZIF-8@MIP/GCE to furosemide was linear at 0.08-100?mol/L,with the detection limit(LOD)as low as 8 nmol/L(S/N=3).The sensor exhibits good selectivity,high sensitivity,superior stability and reproducibility.Thus,this method possesses high potential for the detection of furosemide in human urine specimens and furosemide tablets.2.In the work,a novel molecularly imprinted electrochemical sensor was proposed for sensitive and rapid detection of nitrofurazone(NFZ).The sensor was modified with Cr₂O₃derived from metal-organic framework(MOF),silver nanoparticles(Ag NPs)and biomass carbon(BC)from walnut shells.Among them,Ag NPs are grown on the surface of Cr-MIL-101 to obtain Cr-MIL-101/Ag,and then calcined with BC to obtain a composite material BC/Cr₂O₃/Ag.This material improves the effective surface area and electron transfer capability of the electrode to increase current response.Adding molecularly imprinted polymer(MIP)to the surface of composite materials can improve the specific recognition ability of modified electrodes for NFZ.MIP was prepared by precipitation polymerization using acrylamide(AM)and?-methacrylic acid(MAA)as bifunctional monomers and NFZ as the template.Under the most suitable experimental environment,the differential pulse voltammetric(DPV)current response of modified electrode(BC/Cr₂O₃/Ag/MIP/GCE)to NFZ showed a good linear relationship between 0.005-10?mol/L,and the detection limit was0.003?mol/L.This sensor has high sensitivity,selectivity,reproducibility and stability.Moreover,BC/Cr₂O₃/Ag/MIP/GCE was applied for the detection of NFZ in real samples.BC/Cr₂O₃/Ag/MIP/GCE provides a reliable approach for determination of NFZ in biological fluids.