Immobilization of cholesterol oxidase in ordered mesoporous silica based materials and its activity study

Abstract

Cholesterol detection has much importance and researchers have developed many kinds of biosensors but still the lack of a rapid, cheap and efficient biosensor is clearly visible. In this study, Meso-structured Cellular Foam (MCF) materials have been investigated as a support for the immobilization of cholesterol oxidase. For this purpose, MCF was synthesized, characterized and modified with amino groups using amino-alkoxysilane. The amino functionalized MCF was further modified by glutaraldehyde. The characteristic pore structure of MCF was confirmed with X-ray diffraction (XRD) while the surface area and pore width were determined with surface area analyzer using nitrogen adsorption-desorption technique. The morphology of MCF was investigated using Field Emission Scanning Electron Microscopy (FESEM) while functional groups were detected by Fourier Transform Infrared Spectrophotometry (FTIR). Both amino and glutaraldehyde modified MCF were used for the immobilization of cholesterol oxidase. The activity of free and immobilized enzyme were determined by continuous spectrometric rate determination method. The activity of free enzyme was 0.06170 unit/mL and that of residue solution was 0.00240 and 0.00016 unit/mL for glutaraldehyde and amino functionalized MCF, respectively. The very low absorbance of residue solutions compare to that of free enzyme indicates that the immobilization was successful. So modified MCF can to be a good support for enzymes and bulky bio-molecules.