Graphene Electrochemical Sensor And Its Application In Biomedicine

The unique structure of graphene(GR)gives it novel properties,such as large specific surface area,high thermal conductivity and special electron transport properties.Graphene has aroused widespread interest among researchers.Recently,GR-based composites have combined the properties of their respective nanostructures,and many interesting applications have been discovered,from environmental science to energy conversion to sensors.It is worth noting that conductive polymer / GR nanomaterial composites have proven to be very especial properties as sensing platforms.Biosensors are a new type of analytical instrument that enables the detection of amino acids and biological cells and provides fast,quantitative and high-throughput analysis without the need for a professional operator.Based on the specific recognition characteristics of biomolecules,the recognition element interacts with specific analytes and is then closely coupled to a form of sensor that converts the signal triggered by the recognition element into a quantifiable electrical,thermal or optical signal.There are many biometric elements,such as enzymes,antibodies,microbial cells,etc.,which have been used to make biosensors.Biosensors are exceptionally specific and sensitive,fastresponding,low-cost,and user-friendly.Biosensors have received extensive attention as analytical tools for medicine,agriculture,food safety,bioprocessing,industrial and environmental monitoring.In this thesis,a exfoliated graphene(GR)dispersion was prepared by using PVP dispersant.A simple green L-Trp electrochemical sensor was prepared by modifying the glassy carbon electrode(GCE)with the graphene dispersion.Optimizing the experimental conditions,the prepared biosensor can obtain higher detection sensitivity and a wider detection range.Then,the prepared sensor was further improved,and another L-Trp electrochemical biosensor of mechanically exfoliated graphene and PEDOT:PSS composite modified glassy carbon electrode was constructed by using graphene and conductive polymer PEDOT:PSS.GR / PEDOT:PSS / GCE exhibits good electrocatalysis,stability and repeatability for the oxidation of L-Trp.Finally,the yeast microbial sensor was prepared by using GR / PEDOT:PSS composite modified electrode.It has good electrochemical activity by electrochemical impedance spectroscopy(EIS)method.The microbial sensor has high sensitivity and the preparation method is simple.It has great research value.