Fabrication Of Gold Nanoparticles-based Electrochemical Biosensors And Their Applications In Biological Sample Analysis Presented

Carbon fiber microelectrode(CFME)has the advantages of high spatial resolution,small tissue damage and high detection sensitivity due to its extremely small electrode size,which can be used in quantitative analysis of various biological micro-components.Gold nanoparticles is a kind of nano-material with special photochemical characteristics,which has the advantages of good biocompatibility,strong conductivity and good dispersibility.It has a wide application prospect in biomedicine,material science and other fields.In this paper,gold nanoparticles and nano-composite materials were used to modify CFME to improve the sensitivity and selectivity of CFME,and the modified electrode was used to detect biological samples.The specific research contents are as follows:(1)An eletrochemical detection method was established for aloe-emodin(AE).The linear gold nanoparticles(LGNs)were prepared by reducing chloroauric acid with trisodium citrate.The LGNs were deposited on CFME by one-step potentiostatic deposition,and the electrocatalytic performance of the CFME towards AE before and after modification was investigated.The results showed that the oxidation peak current of linear nano-gold modified carbon fiber microelectrode(LGNs/CFME)has a good linear relationship with AE concentration in a certain range.The modified electrode has good reproducibility and simple preparation,and can be used for quantitative of AE in aloe juice.(2)Stable spherical gold nanoparticles with a particle size of 50 nm was synthesized,combined with cage-like and star-like gold nanoparticles with the same size were modified on the surface of carbon fiber microelectrodes by one-step potentiostatic deposition method,and the stable modified electrode was obtained by optimizing the electrodeposition time.The electrochemical behavior of catecholamine neurotransmitters at different modified electrodes was investigated by differential pulse voltammetry(DPV)and cyclic voltammetry(CV).The optimal gold nanoparticles modified electrode(GNs/CFME)was used for the quantitative determination of dopamine(DA)in mouse serum samples.(3)Small-sized spherical gold nanoparticles(Au NPs)were synthesized by a simple method.Gold nanoparticles with a particle size of 6 nm were prepared by reducing chloroauric acid with trisodium citrate at room temperature.The carbon fiber microelectrode was modified with gold nanoparticles(Au NPs/CFME)by one-step potentiostatic deposition for the detection of catechin.The results showed that Au NPs/CFME has a good electrocatalytic effect on catechin,which could be used for quantitative analysis of catechin in green tea samples.(4)Gold nanoparticles(Au NPs),choline(Ch)and graphene quantum dots(GQDs)were deposited on the surface of carbon fiber microelectrode by potentiostatic deposition,and composite modified GQDs/Ch/Au NPs/CFME was prepared.Due to the synergistic effect of modified materials,the GQDs/Ch/Au NPs/CFME exhibits obvious electrocatalytic effect for positively charged DA and significant shielding effect on negatively charged ascorbic acid(AA).The modified electrode can eliminate the interference of AA and detect DA with high sensitivity,and has been successfully used for the determination of DA in mouse serum in the presence of high concentration of ascorbic acid.