The Preparation Of Multi-functional Metal Nanocomposites And Their Application In Biochemical Sensing

In recent years,nanocomposite materials combining the advantages of both nanomaterials and composites,have received much attention.In this thesis,taking advantages of various materials,such as metal,graphene,conductive polymer,carbon quantum dot and metal oxide,several nanocomposite materials with multiple functions were successfully synthesized.And by means of conventional detection methods,such as electrochemistry,surface enhancement Raman scattering and fluorescence,the application of these nanocomposites in biochemical sensing was investigated.The main contents of this thesis are as follows:?1?Au@graphene?AG?core-shell nanoparticles with high conductivity,catalytic activity and stability,were synthesized and doped into poly?3,4-ethylenedioxythiophene??PEDOT?to build PEDOT/AG nanocomposite material for the electrochemical detection of paracetamol.The PEDOT/AG nanocomposite exhibited high conductivity and excellent catalytic activity toward the redox of paracetamol,and owing to the presence of AG nanoparticles,the electrochemical signals and peak profiles of paracetamol at the PEDOT/AG modified electrode were significantly improved.Under optimum conditions,the PEDOT/AG modified electrode exhibited high sensitivity to paracetamol over a wide linear range of concentrations from 0.15?M to 5.88 mM,with a detection limit of 41 nM.Furthermore,the fabricated sensor exhibited high selectivity and long-term stability,and was capable of detecting paracetamol in real pharmaceutical samples with satisfying accuracy.?2?Graphene-isolated-AgCu?AgCu@graphene,ACG?nanoparticles were synthesized first,and after modification with amphiphilic materials,they were successfully used for the Raman detection of malachite green.With AgCu alloy core as surface-enhanced Raman scattering?SERS?substrate and graphitic shell as protective materials,ACG nanoparticles possess good stability.Treating ACG nanoparticles with lipophilic alkyl chains and hydrophilic polyethylene glycol chains,functionalized ACG?FACG?nanoparticles were obtained.FACG nanoparticles could be dispersed in a variety of solutions,including organic low polar and water-miscible high polar solutions.With FACG nanoparticles as the internal standard,we have constructed a ratiometric SERS sensing system for the detection of malachite green.?3?Near-infrared carbon quantum dots?NCQD?and manganese dioxide ?MnO₂?nanoflowers were synthesis and employed to form a nanocomposite for the fluorescent detection of glutathione?GSH?.Based on the prepared NCQD-MnO₂nanocomposite,a?turn-on?fluorescence nanoprobe for efficient detection of GSH was developed.In the nanosystem,NCQD was used as fluorescence reporter,while MnO₂ nanoflower was employed as the fluorescence quencher and the recognition unit for GSH.When GSH was introduced,MnO₂ was reduced to Mn²⁺,which resulted in a?turn-on?fluorescence signal of NCQD.The nanoprobe displayed high sensitivity toward the detection of GSH,with a detection limit of 2.8?M.Moreover,via fluorescence imaging,the nanoprobe was applied to monitor the change of the intracellular GSH in living cells,which successfully demonstrated its value for practical application in biological systems.