The Preparation Of Semiconductor Nanomaterial And Its Application On The Biosensor

With the rapid development of nanoscience and technology,preparation methods for nanomaterials have been evolved very quickly.There are various preparations methods for nanomaterials including chemical methods,physical methods and integrated methods.Chemical methods include chemical precipitation method,hydrothermal method,phase-transfer method,interface method and sol-gel method.Physical methods include inert gas evaporation method,laser vaporization method,ball milling method and arc process method.Integrated methods include supersonic and co-deposition method,pulsed laser deposition,microwave synthesis method and so on.Nanomaterials have been widely used in many areas such as electricity,light magnetism,catalytic oxidation and so on,due to unique particles structure and physical and chemical properties.Biosensor research is a new and growing research field,which is associated with physics,chemistry,electronics and computer science.In addition,biosensors can meet the ever-increasing need in rapid analysis and test of physical and chemical properties for materials.Over the past few years,researchers have focused their study on biotechnology and nanomaterials.Electrochemical biosensors have become a top priority.More importantly,unique features possessed by nanomaterials can satisfy requirements of various electrochemical biosensors,for instance,miniaturization,rapidness,multi-functionalization of biosensors.Using nanomaterials as the building materials for biosensor can not only enhance its feature in rapid detection and reproducibility,but also improve its sensitivity in detection of biological molecules.Moreover,scientists spent a lot of efforts in semiconductor nanomaterials,which further promote the rapid development in electrochemical biosensors.Ascorbic Acid,or vitamin C,is indispensable to humans and animals and it exists in body fluids and tissues in body of humans and animals,fruits and vegetables.Ascorbic Acid is often used to treat scurvy,bleeding,detoxification,etc.It can also improve our body's immune capability.Dopamine is a very important component to control nerve conduction of humans and animals.Dopamine is commonly used to assist in transmitting neural signals between cells and responsible for controlling the biological information.However,our body will get serious sick if the amount of dopamine is out of the normal limit in our body,for instance,Parkinson's Disease,Schizophrenia and so on.Uric Acid,isthe end product of purine metabolism,which is an important part to control health of our body.This thesis is focused on the synthesis of semiconductor nanomaterials and its applications in electrochemical biosensors.Two types of semiconductor nanomaterials were synthesized,such as ZnO/Au-nanoparticles and Ni Co-nanoparticles.Besides,the as-synthesized nanomaterials were used to modify bare electrode in order to detect catalytic oxidation properties of Ascorbic Acid,Dopamine and Uric Acid.The content are shown as follows:(1)The first chapter gives general introduction to synthesis of nanomaterials,semiconductor nanomaterials and electrochemical biosensors,such as cell electrochemical sensors,electrochemical enzyme sensors,electrochemical DNA sensors and electrochemical immune sensor and so on.(2)The second chapter describes the preparation and characterization of ZnO/Au-nanoparticles via in-situ plasma sputtering-assisted method and their application for electrochemical sensing of ascorbic and uric acid simultaneously.The ZnO/Au-nanoparticles were characterized by SEM,TEM,and HRTEM.In addition,the bare electrode was modified to detect the electrochemical properties of AA and UA by three electrode system.(3)The third chapter introduces the synthesis and characterization of NiCo-nanoparticles via chemical synthesis method and their application as a new material for electrochemical sensing of AA,DA and UA.Firstly,the bare electrode was modified with the NiCo-nanoparticles and was used for electrochemical sensing of AA,DA and UA using the modified electrode.Results showed that semiconductor nanoparticle-modified electrodes can significantly improve the properties(i.e.,sensitivity and selectivity)of the biosensors fabricated with the modified electrodes.These studies demonstrate that semiconductor nanoparticles may have great potential in clinical diagnostics.