Non Hazardous synthesis of graphene and its application in the preparation of L-Asparginase based biosensor obtained from Bacillus cereus strain for the detection of leukemia

Abstract

High quality graphene oxide was synthesized using expanded graphite following a modified Hummer's method. This method is facile, inexpensive and avoids use of strong acids. To exfoliate, the Graphene Oxide (GO) sheets were thermally exfoliated by rapid heating at 1050°C for 30 seconds under an Argon atmosphere. Further the antileukemic enzyme Asparaginase was isolated from a bacterial source, Bacillus cereus strain BHU-MBU BC1 (ACCESSION No. KJ472206). The isolated enzyme was further purified in a single step through DEAE-Sepharose column (2.0 × 10.0 cm) at 4°C. Kinetic parameters of the as purified enzyme were thoroughly studied. As purified enzyme was further attached to graphene. It was observed that graphene conjugated enzyme showed the enhanced activity and the reusability of the enzyme was found to be 12 times retaining activity upto 80%. The temperature optima of the immobilized enzyme were also found to be improved from 45° to 60° C.