Functionalized Polyacrylonitrile Nanofibrous Membranes for Covalent Immobilization of Glucose Oxidase

Nanofibrous membrane (NFM) with uniform morphology and large surface area was prepared from 10% solution of polyacrylonitrile (PAN) in N,N-dimethylformamide by electrospinning technique. NFM was chemically modified for use as a support for the immobilization of glucose oxidase. Chemical modification of NFM was carried out by two different methods. In the first method, the cyano groups of PAN were modified to amino groups by a two-step process, while in the second method the carboxylic groups were generated first and then further reacted with hexamethylene diamine to create a reactive spacer arm for the immobilization of enzyme. Scanning electron microscopy studies showed that the surface morphology of NFM was not changed by chemical modification and its mechanical strength was improved. The immobilized glucose oxidase (GOx) retained 54 and 60% of its original activity up to 25 cycles with the PAN NFMs modified by the first and the second method, respectively. The GOx-immobilized NFM from the second method showed promising performance with higher enzyme immobilization, activity retention, and favorable kinetic parameters.