Construction Of Graphene Three-dimensional Structure Detection Electrode And Its Sensing Of Escherichia Coli And Dopamine

Graphene is a single-layer,two-dimensional honeycomb structure substance made of SP~2 hybridized carbon atoms that are closely packed.The structure,properties,and uses of graphene were the subject of a study boom after its discovery.As scientists continue to examine the properties of graphene in greater detail,it is found that its high carrier mobility,high conductivity,and strong biocompatibility are ideal for use in the field of biosensing,which can significantly enhance the convenience,sensitivity,integration and other characteristics of biosensors.However,due to the ease with which graphene nanosheets accumulate and the resulting agglomeration issues,the increase efficiency of the mechanical and electrical properties of graphene-based biosensors is only moderate.As research progressed,it became clear that adding new morphological structures to existing materials would be necessary to fully leverage graphene in Superior performance in macroscopic applications.Because of this,we have prepared graphene materials with a unique structure in the hopes that they can be used in the field of biological and microbial small molecule sensing.On the one hand,we used a hydrothermal approach to make a graphene aerogel with a three-dimensional porous network,with the assistance of Escherichia coli antibodies(anti-E.coli),we constructed a biosensor foam based on it for real-time sensitive detection of Escherichia coli(E.coli);on the other hand,we used a nickel template and hydrazine monohydrate as a reducing agent to prepare graphene foam with three-dimensional macropores and high specific surface area,and we used this as the foam substrate to construct an electrochemical detection electrode for high-precision detection of dopamine small molecules.The following is the key work we’ve accomplished:1.A graphene aerogel-based biosensor electrode for Escherichia coli was conceived and constructed.With high specificity and sensitivity,the electrode can quickly identify Escherichia coli.We prepared high-quality single-layer graphene oxide solution using the improved Hummer method,created graphene aerogel(GA)with a three-dimensional porous network structure through hydrothermal reduction and freeze drying,and increased the specific surface area and adsorption site of the electrode.Then use this as a framework for functional modification,The detection substrate(GA-anti-E.coli foam)may specifically capture E.coli with the aid of an antibody.We examined the resistance and impedance changes that occurred throughout the capture process using the detection electrode to conduct real-time sensing of E.coli.The findings demonstrated that the prepared E.coli sensing electrode had regular variations and continued to react to E.coli concentrations as low as 10 cfu/m L.Lastly,in order to better describe this detection process,we used Zsim Demo software to construct an equivalent circuit for the detection electrode.By analyzing the equivalent circuit,the binding of bacteria on the detection substrate can be obtained,providing a new approach for real-time sensing research of bacteria.2.A graphene foam(r GO foam)with a good self-supporting structure was prepared using the template method using metal foam nickel as the template and graphene oxide solution as the raw material.After transferred the foam structure to the indium tin oxide(ITO)conductive glass,we employed the electrochemical workstation CHI660 to detect dopamine using cyclic voltammetry and differential pulse voltammetry.We found that the prepared dopamine electrochemical sensor has a greater response current and higher sensitivity than the conventional glassy carbon electrode.In the concentration test,the peak oxidation current of dopamine showed a good linear pattern in the concentration range of 0.5μM to 50μM,and the detection limit is less than 0.5μM.These findings demonstrate that the prepared r GO foam-ITO detection electrode has the characteristics of rapid response and high sensitivity,presenting a novel detection technique for the in vitro rapid and precise detection of dopamine.