The Development And Application Of Electrochemical Sensors Based On Nanocomposite

Biomolecules such as enzymes, antigens/antibodies or DNA exhibit nanoscaledimensions comparable to the dimensions of nano-materials (NM) such as metalnanoparticles and graphene. These size similarities pave the way to combine theunique electronic, photonic, and catalytic properties of NM with the nature-evolvedselective binding and catalytic functions of biomolecules by integrating the native andsynthetic components into hybrid systems. Extensive research efforts were directed inthe past few years towards the development of biomolecule–NM hybrid assembliesand their application to electrochemical biosensors. The present article preparedseveral bioelectronic sensors based on biomolecule, NM and their hybrid. The contentof this dissertation were as follows:(1) A DNA modified glass carbon electrode (DNA/GCE) by potentiostaticmethod for Rotundine (RT) determination was prepared. The results indicated thatthis voltammetric sensor exhibited a special recognition capacity towards RTdetermination. Under the optimize condition, there is a linear relationship between theresponse peak currents and the RT concentrations in range from5.6×10-6mol·L-1to2.8×10-4mol·L-1with detection limit of2.4×10-7mol·L-1.(2) Graphene/DNA composites were synthesized by electrolytic exfoliation, anda chemical reduction method was used to fix the gold nanoparticles on the surface ofgraphene/DNA composites to produce the graphene/DNA/gold nanoparticles(Gr/DNA/AuNPs) composites. Finally, a novel non-enzymatic biosensor for glucosebased on Gr/DNA/AuNPs modified electrode was prepared. Under the optimalconditions, the biosensor shows a linear range with a detection limit of1.2×10-5mol·L-1(S/N=3) from8.0×10-5to5.0×10-2mol·L-1. The biosensor shows goodreproducibility, stability and can avoid the commonly coexisted interference. Theestablished method was used for the detection of glucose in human serum sampleswith satisfactory results, and the recovery was between97.4%and102.8%.(3) Instead of AuNPs, silver nanoparticles were got by a chemical reductionmethod and used to fabricated another voltammetric sensor with Graphene/DNAcomposites. The electrochemical sensor was used to investigate the electrochemical behavior of acyclovir and benorilate. The results indicated that this voltammetricsensor exhibited a special recognition capacity to determine as well as had highsensitivity. The Gr/DNA/Ag modified electrode shows a linear voltammetric responsein the range of5.89×10-6~1.0×10-4mol·L-1with detection limit1.2×10-7mol·L-1for acyclovir. For benorilate, we also got a linear response between current andconsentrations from9.48×10-6~3.67×10-5mol·L-1with detection limit1.49×10-6mol·L-1.(4) A novel voltammetric sensor based on Poly (L-arginine) and goldnanoparticles was constructed by electrochemical method and used for sensitivedetermination of dopamine (DA). The poly (L-argenine)/AuNPs modified electrodeshowed excellent stability, high sensitivity and good reproducibility which led us toconstruct a practical DA voltammetric sensor successfully. This modified electrodeexhibited a linear voltammetric response for DA in the range from8×10-7~1×10-4mol·L-1with a detection limit of1.0×10-7mol·L-1. The detection of DA was found tobe unaffected by the presence of ascorbic acid and uric acid. The modified electrodewas applied to assess the contents of DA in dopamine hydrochloride injection with arecovery of96.5%~104%.