Conjugated polymer nanocomposites for bio-active nanoprobes

Abstract

In recent, conjugated polymers (CPs) have been reported as excellent sensing substrates due to its intrinsic opto-electric variability at each oxidation or reduction state. In particular, polyaniline (PAni) has attracted as a sensing material because of its easy synthesis, high conductivity, the controllable opto-electric property. Thus, PAni polyplex can perform as a suitable mediator of electron transfer in enzyme-based redox reactions for electro-chemical sensor. In addition, nano-sized PAni varies its color according to redox states by biological doping for bio-optical sensing. In this thesis, PAni nanocomposites were fabricated as a biomedical nanoprobe. First, porous PAni nanocomposite, named as PAni nanoskein (PANS), was synthesized using PAni and diverse solvents at sequential heating and cooling process. Interestingly, surface area-increased PANS was fabricated in a nanoscale with because of extraordinary polymer structure and solvent effect. Thus, PANS presented identifiable redox sensing potential by a biological doping for optical bio-active nanoprobe. On the other hand, for a detail diagnosis of cancer using magnetic resonance (MR) imaging, magnetic PAni nanohybrid (MPNH) was fabricated for a multi-sensing nanoprobe that it was consist of magnetic nanoparticle and PAni matrix. MPNH were synthesized by modified thermal decomposition method and then enveloped by amphiphilic surfactant to conjugate with cancer targetable ligands. Thus, biomarker-targetable MPNH demonstrated potentials for optical redox state sensing and MR imaging for target cancer cells, simultaneously. In conclusion, PAni nanocomposites were designed and manufactured for a biomedical sensing. Due to opto-electric characteristics of PAni, PAni-based nanoprobes demonstrated redox-specific sensing activity for target cancer cells.