Applications Of Carbon Nanotubes As Bioprobes

There has been intense interest in carbon nanotubes since their discovery by Iijima in 1991 mainly because of their structural, electronic, and mechanical properties. Carbon nanotubes behave electrically either as metals or as semiconductors, depending on their atomic structure. The subtle electronic properties suggest that carbon nanotubes can be used as a newly electrode material in electrochemical reactions, representing a new application of carbon nanotubes.In this thesis, we have studied applications of the multi-walled carbon nanotubes (MWNTs) as biological probes in two parts. In part one, MWNTs were treated with acid by reported method and the carboxylic acid groups were introduced on the MWNTs surface. Then the acid-treated MWNT was cast on a glassy carbon or a gold electrode to form a carbon nanotube film modified electrode. It had been found that this modified electrode showed very stable electrochemical behavior and could be used to catalyze such as nitric oxide, dopamine and tryptophan. At the same time, the experimental conditions were optimized. Under the chosen conditions, oxidation peak currents of those substances were proportional to their concentrations in the wider range with lower detection limit. The methods were successfully applied to determine simulant or actual samples. In part two, by use of solution phase near-IR spectroscopy we report the measurement of the acidic sites in acid-treated soluble samples of carbon nanotubes. Then the interactions of colloidal particles of MWNTs with DNA and cationic dyes have been studied in detail. Consequently, whether DNA or cationic dyes aggregated on the surface of colloidal particles of MWNTs hydrosol. And the mechanism of interaction had been discussed .