Preparation Of Novel Carbon Nano-Materials Modified Electrods And The Study Of Their Application In Biosensing

Sensitive measurement of biomolecules is a critical need both for modern biochemical and biomedical research. So electrochemical sensors and biosensors are widely used for this purpose due to their highly sensitivity, quick response, simple instrument and easy miniaturization. One of the key factors of the sensing performance of electrochemical sensors and biosensors is modified material. As one kind of attractive carbon material, graphite nano-material attracted a lot of attention in the field of electochemical sensors. Based on the graphite nano-material of graphite nanosheets and graphene, chemical modified electrodes were prepared and used for the sensing performance of biological molecules.1. The electrocatalytical oxidation of dihydronicotinamide adenine dinucleotide (NADH) based on exfoliated graphite nanosheet (GNSs) modified glassy carbon (GC) electrode was firstly explored. The GNSs/GC electrode showed favorable electron transfer for NADH oxidation and the oxidative peak potential was decreased to +0.32 V vs. Ag/AgCl. The electrochemical sensor based on the GNSs/GC electrode exhibited very excellent detection performance for NADH, which are comparable to or better than those of previously reported most carbon nanomaterials modified electrodes.2. The method of simple mechanical ball milling was used to exfoliate the big particles of graphite into small nanosheets, which bring about a large number of edge plane sites.This work studied the difference between the properties and ball milling conditions about KS-6. Electrochemical behaviors of NADH was investaged at the ball milling KS-6 modified electrode, which showed a lower oxidation overpotential of 0.28 V vs. Ag/AgCl and excellent sensing performance. This showed that the commercial, large-scale processing of graphite nano-materials has broad application prospects in constructing the biological devices based on dehydrogenase.3. The graphene nanosheet (GNS)-single-walled carbon nanotube (SWCNT) hybrid film was prepared and characterized by scanning electron microscopy (SEM). Electrochemical behaviors of K3[Fe(CN)6] and six kinds of important electroactive biomolecules were studied at the GNS-SWCNT modified glassy carbon electrode (GNS-SWCNT electrode). Remarkably enhancing electrochemical responses toward seven probe molecules were observed at the SWCNT-GNS/GC electrode relative to that at only SWCNT/GC or GNS/GC electrode. The sensing performance of the SWCNT-GNS/GC electrode towards dopamine (DA) and acetaminophen (APAP) were investigated and compared with previously reported those based on CNTs or graphene modified electrodes. The results clearly demonstrated that highly sensitive detection was obtained at the SWCNT-GNS/GC electrode. These indicate that the SWCNT-GNS hybrid film may be a better choice for constructing electrochemical sensing of some biomolecules.