Designing and surface modification of zinc oxide nanoparticles for biomedical applications

The present study aimed to work out a simple and high yield procedure for the immobilization of beta galactosidase on bioaffinity support, concanavalin A (Con A) layered zinc oxide nanoparticles (ZnO-NP). Thermogravimetric analysis of bioaffinity support revealed 4% loss in weight at 600 degrees C whereas its thermal decomposition was observed at 530 degrees C by differential thermal analysis. No significant change was noticed in the band intensity of pUC19 plasmid after its treatment with Con A layered ZnO-NP. Comet assay further exhibited negligible change in tail length of comet after treating the lymphocytes by bioaffinity matrix. The bioaffinity matrix binds 89% of the enzyme activity. Atomic force microscopy analysis showed that the prepared matrix has an advantageous microenvironment and large surface area for binding significant amount of the enzyme. The functional groups present in native and parent compound were monitored by Fourier transform-infrared spectroscopy. Michaelis constant, K-m was 2.38 and 5.88 mM for free and immobilized beta galactosidase, respectively. V-max for the soluble and immobilized enzyme was 0.520 mM/min and 0.460 mM/min, respectively. Concanavalin A layered ZnO-NP bound beta galactosidase exhibited a shift in the temperature-optima and retained nearly 86% activity even after its 6th repeated use. (C) 2011 Elsevier Ltd. All rights reserved.