Hybrid Zinc Oxide Nanoparticles for Biophotonics

A novel Zinc oxide (ZnO)-Hydrogel fluorescent colloidal semiconductor nanomaterials system is presented for potential bio-medical applications such as cell and tissue imaging. ZnO nanoparticles (NPs) synthesized using arc discharge technique has been conjugated to bio-compatible Poly N-isopropylacrylamide (PNIPAM) based hydrogel polymer matrix. The stability and fluorescence of ZnO nanoparticles are significantly enhanced using hydrogel colloidal dispersion. Photoluminescence spectroscopy indicates approximately 10 times enhancement in fluorescence in ZnO-Hydrogel colloidal system compared to ZnO-Water system, confirming the surface modification of ZnO nanoparticles by hydrogel polymer matrix. Femtosecond time resolved fluorescence measurement demonstrates that the fluorescence is due to the enhancement in absorption by the ZnO nanoparticles due to scattering by PNIPAM nanospheres.