Quantum dots and nanostructured conducting polymers for biosensing applications

Numerous methodologies are currently being employed for the preparation of nanomaterials in customised morphologies. In this paper, we outline recent progress in our laboratory to develop nanostructured inorganic semiconductors - quantum dots (QDs), and nanostructured organic semiconductors based on polyaniline (PANI), for biosensing applications. Blue luminescent CdTe QDs were prepared directly from an aqueous solution via photo-irradiation and used to demonstrate a simple homogenous DNA sensing platform. Highly luminescent CdTe/CdS core/shell QDs with enhanced photostability were also prepared in an aqueous phase using thioacetamide as a sulphur source. PANI nanostructures have been prepared using a template-free method and the mechanism of their formation is currently being investigated. The effect of having amino acids in the polymerisation solution and using polymeric acids as dopants on the morphology of the nanotubes has been examined. An electrochemical DNA sensor was constructed using PANI nanotubes doped with poly(methyl vinyl ether-alt-maleic acid).