Zinc Oxide Based Hydrogel for Bio-Applications
S. John, S. Marpu, Y. Fujita, M. Omary, A. Neogi
University of North Texas, US
Keywords: ZnO, Poly N-isopropylacrylamide, fluorescence, litetime, cell-imaging
Abstract:ZnO can be elected as a potential replacement for conventional dyes and toxic quantum dots in bio-medical applications owing to its low toxicity and high photo stability. The major drawback of using semiconductor nanoparticles including ZnO for bio-applications is its insolubility in aqueous media. Meanwhile, hydrogels made from Poly (N-isopropylacrylamide) are being used in various bio-medical applications due to their aqueous inner environment, biological compatibility, and feasibility for conjugating with biological molecules. This paper presents a novel ZnO-Hydrogel based fluorescent colloidal semiconductor nanomaterials system for bio-medical applications such as cell imaging. UV-emitting ZnO rod particles of 200~300nm in diameter of excellent quality were synthesized using gas evaporation method. Since biological applications require water soluble nanomaterials, ZnO nanoparticles are first dispersed in water by ball milling method, and their aqueous stability and fluorescence properties are enhanced by incorporating them in bio-compatible Poly N-isopropylacrylamide (PNIPAM) based hydrogel polymer matrix. The optical properties of ZnO-Hydrogel colloidal dispersion versus ZnO-Water dispersion were analyzed. Fluorescence Spectroscopy indicates approximately 10 times enhancement of fluorescence in ZnO-Hydrogel colloidal system compared to ZnO-Water system, confirming the surface modification of ZnO nanoparticles by hydrogel polymer matrix.