Material Science and Engineering

Biography

Biography: Bichitra Nandi Ganguly

Abstract

Metallic oxide (MO) for example GaO(OH), ZnO nanoparticles(NPs) (grown in the template of large surface active molecules) are biologically useful, luminescent material. These can be used for multifunctional purposes, such as biosensor, bioimaging, and targeted drug delivery. Though, ZnO is categorized as: “generally recognized as safe” (GRAS) but ZnO nanoparticle system may be cytotoxic. ZnO nanosystem could be of important relevance in the context of nanomedicine, where targeted treatment of biological systems at molecular level is a necessity. Preparation of metal-oxide (MO) nano system (quantum dots) with their surface modification and bio-conjugation for selective destruction of tumor cells and their potential use for drug delivery applications is the cardinal issue of this presentation. The relevant literature studies suggest that there is an urgent need to develop new classes of anticancer agents and recent studies demonstrate that ZnO nanomaterials hold considerable promise. Similarly GaO(OH) is also another wide band gap semiconductor nano oxide, which could be tagged with radioactive Ga -68 in soluble form to be selectively applied to tumor cell uptake and used for diagnostic purpose using positron emission tomography (PET). In this context, sol-gel chemical method was used to develop the uniform size MO nanoparticles, agglomeration of the these particles to large sizes was prevented due to surface charge density of biologically relevant ligands used in the medium. The characteristic crystalline structure of wurtzite ZnO and orthorhombic GaO(OH) nano particles in the X-ray diffraction analysis has been confirmed. Also, the structural morphology and size determination through TEM, and the band gap analysis of the synthesized particles have been performed. For the detailed micro structural analysis and any surface conjugation related studies in the micro crystalline nanomaterials, (with respect to the ligand concentration), the material has been subjected to positron annihilation spectroscopic studies using coincidence Doppler broadening line shape studies with ‘S’ and ‘W’ parameter analysis. A two detector coincidence Doppler broadening(CDB) of positron annihilation radiation studies to probe the differences of highly pure as prepared MO nano material samples and the bio-templated sol-gel grown sample, considering their ratio curves of CDB annihilation radiation, has been undertaken. The results show important surface structural features (owing to elemental analysis) of the attached bio-ligands. The presence of MO nano-particles conjugated bio-ligands have been also identified with the characteristic stretching frequencies in FT- I.R. spectroscopic studies. Fluorescence emission characteristics of the NPs have also studied. Quenching of the fluorescence intensity of the GaO(OH)-NP through bio-conjugation exhibited Förster resonance energy transfer(FRET) mechanism. Further, in vitro studies of the cytotoxic effects of the surface conjugated nanoparticles are in progress.