A Molecular Imprinted Quartz Microbalance Sensor Based On Nano-porous Gold For Cholesterol Detection

Cholesterol is an important part of the life structure in the human body,which plays an important role in the process of biological material and life activities.High incidence of disease is associated with cholesterol levels in the body.People also need to control their cholesterol intake for fitness.The quantitative determination of cholesterol concentration is of great significance in the field of clinical diagnosis and food detection.Electrochemical biosensor has many advantages in the target detection,such as very high specific recognition ability,high sensitivity,less sample consumption,small volume.Those advantages make it of great significance in cholesterol test method study.Molecularly imprinted polymer has very good stability,good selectivity and affinity,and timeliness.Combined with no enzyme detection technology,sensor of molecular imprinting technique based on nanomaterials,improves the sensitivity,precision,detection limit,continuous performance,etc.greatly during the detection of biomolecules.Nanoporous gold has larger surface,small relative density,high conductivity and good biocompatibility.In this paper,the effect of the selection of functional monomers and crosslinking agents on the properties of the sensor material was investigated,with cholesterol as template molecule of MIPs.In the material synthesis process,the nanoporous gold is loaded onto the surface of the quartz crystal gold electrode.The polymer film was formed by electropolymerization on the nano-porous gold.The template was then taken to form a molecularly imprinted membrane that had a recognition effect on cholesterol molecules.By means of surface topography,electrochemical test,and quartz microscale as an important test method for material performance.The specific work is as follows:(1)2-hydrophobic benzimidazole has two nitrogen atoms and a sulfide,and the cysteamine has both amino and sulfur groups.The sulfur base can guarantee a very good binding effect with the nano-porous metal.The amino group can also react with the hydroxyl group in cholesterol molecules.2-MBI as a functional monomer,cysteamine as crosslinking agent,DDT as the pore agent in the polymerization solution.Molecularly imprinted materials were prepared by electropolymerization in nano-porous gold matrix.When the material is synthesized,the NPG is directly loaded onto the surface of the quartz crystal gold electrode.Through STEM characterization,nano porous gold is a very good three-dimensional porous material.The molecularly imprinted membranes synthesized by electropolymerization have a very good binding effect on the surface of NPG.By cyclic voltammetry test,impedance test and quartz microscale comparison test,etc.the synthesis of molecularly imprinted membranes with specific identification of cholesterol.(2)With quartz microscale as an important means of characterization,the detection accuracy,detection limit and linear detection range of MIPs sensor materials with 2-MBI as functional monomers were tested.Through a series of tests,we can know that compared to the detection of glucose and uric acid,this material has a characteristic recognition effect on cholesterol.The sensor material of molecularly imprinted polymer film based on NPG synthesized by electropolymerization,has a valid detection limit of 1.25?M to 750 ?M,and the linear detection range is 30 ?M to 700 ?M,and the linear correlation coefficient is 1.Property tests indicate that this sensor material has good Repeatability effect,good timeliness within 2 weeks,and has good detection effect in weak acid environment.(3)To explore in the form of molecularly imprinted polymeric film electric polymerization,with more sulfur amino,key contribution,to explore the two functional groups in the universality of the molecularly imprinted membrane cholesterol detection.Use dopamine with amino,sulfur and hydroxyl as functional monomer,cysteamine as crosslinking agent in the synthesis of molecularly imprinted membranes.The MIPs based on NPG was synthetic by electropolymerization.Dopamine and cholesterol molecules are biologically well integrated.At the same time,the molecular imprinting film was formed by the self-assembly of dopamine,and the changes of functional groups in the process of electropolymerization were discussed.The synthesis of MIPs was characterized by TEM,cyclic voltammetry and impedance.Through the Raman tests compared various steps and synthesis methods,electric polymerization process,can know the hydroxyl ionization,look for related research,amino and cholesterol molecules generated in the process of electrical aggregation amide functional group.By comparing the methods of electrical polymerization and self-assembly,the electropolymerization method can form a more uniform and stable molecular imprinting film,and the detection process sensitivity and accuracy are improved.