Study On Electrochemical Biosensing Properties Of Porous Carbon Nanomaterials

The development of carbon material has received a great deal of attention in recent years. Particularly, porous carbon materials have been applied to gas separation, water purification, catalyst supports, electrodes for electrochemical double layer capacitors and fuel cells due to their uniform pore sizes, high surface areas and large pore volumes. In recent years, porous carbon materials have been widely applied in electranalysis and obtained satisfactory results. Based on previous study results, we researched and fabricated two kinds of porous carbon materials and studied their electrocatalytical performance, the content was listed below:1. Novel mesoporous carbon fibers(MCFs) were fabricated through a self-templating strategy and solution growth process. MCF modified glassy carbon electrode(MCF/GCE) was proposed for the direct electrocatalytic and simultaneous determination of four DNA bases(guanine(G), adenine(A), thymine(T) and cytosine(C)) using differential pulse voltammetry(DPV) measurement. The MCF/GCE exhibits satisfactory electrocatalytic activity by significantly enhancing the oxidation peak currents and lowering the oxidation potentials toward the four bases when compared with those on GCE. Especially, MCF greatly accelerates the electron transfer of pyrimidine base, which have high oxidation potentials and slow electron transfer kinetics. Moreover, MCF/GCE realizes the simultaneous determination of four DNA bases with low detection limit, high sensitivity and wide linear range. More important, the proposed electrode was successfully applied in the direct detection of bases in herring sperm DNA sample with satisfactory results. Besides, the MCF/GCE shows good long-term stability and reproducibility. These superior performances of MCF/GCE toward purine and pyrimidine DNA bases provide a good possibility for applying the MCF/GCE in our further DNA biosensor research.2. Novel left-handed double-helical chiral carbon nanotubes(CCNTs) were one-step synthesized by carbonization of self-assembled chiral polypyrrole nanotubes, which came from the electrostatic interaction between carboxylic amphiphilic molecules and pyrrole monomers. Different samples were prepared through changing carbonization temperature. These samples were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), N2 adsorption-desorption and X-ray photoelectron spectroscopy(XPS). We present the electrochemical biosensing performance of the prepared CCNTs by using dopamine(DA), ascorbic acid(AA), uric acid(UA), H2O2 and NADH as probes. CCNTs show high electrocatalytic activity towards the above molecules with a decrease of overpotential and a drastic enhancement of anodic currents compared to ordinary carbon nanotubes. Moreover, the influence of carbonization temperature, pore size, different N-bonding configurations(pyridinic N, pyrrolic N and graphitic N) and surface area on electrocatalytic performance of the CCNTs was studied in detail. The results show that CCNT-900 with the largest BET surface area and suitable N-bonding configurations exhibits the best electrocatalytic activity. CCNTs with remarkable electrochemical biosensing capability may be a kind of promising nanomaterial for electrochemical biosensing application.