Preparation, textural and photoluminescence characterization of green fluorescence protein-immobilised Ga-ZnO (GZO)-nanocomposites

•Fine Nanodisk/nanoflower morphology is obtained for Gallium doped ZnO on AlN.•Green fluorescence proteins binding on Ga-ZnO is successfully prepared.•FE-SEM and AFM is used to study surface structures of GZO nanostructures.•Cell viability and biocompatability studied using Human colon cell lines HT 29.•UV light sensor activity is carried out on Ga-ZnO nanodisk/nanoflower thinfilm.

Nanostructured thin films of Gallium doped Zinc oxide (GZO) with nanodisk/nanorods and nanoflower morphologies are fabricated on a piezoelectric substrate. Pure wurtzite phase of GZO with nanostructure morphologies were prepared by a one-step spin coating process, followed by hydrothermal treatment. A non-ionic polymer (polyethylene imine) was used as a structure assisting agent to selectively form the nanodisks or nanoflowers depending on the reaction conditions. The morphology, nanostructure, and physicochemical properties of GZO were studied by X-ray diffraction, scanning electron microscopy (SEM) and Raman spectroscopy. The thicknesses and lengths of the individual GZO nanodisks were measured by FE-SEM. The fine nanodisk and nanoflower structures are obtained. Green fluorescent proteins were immobilised on the as-synthesised GZO nanostructured materials by dip coating. Atomic force microscopy was used to study the surface roughness of the GZO nanodisks, nanoflowers and nanorods. Photoluminescence techniques were used to study the GZO nanodisk structural defects and its optical properties. Fluorescence spectrometry analyses confirmed the binding of green fluorescent protein on the GZO nanostructure surface. The biocompatibility study of GZO nanostructures have been studied using Human HT-29 colon cell lines. Trace levels of green florescent protein immobilised on Ga-doped ZnO nanodisks and nanoflowers showed good activity for UV light sensing.

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