Functionalization of multiwalled carbon nanotubes for enzyme immobilization

A simple strategy for enzyme immobilization onto homo- and hetero-functionalized multiwalled carbon nanotubes (MWCNTs) is described. Homo-functionalization of MWCNTs can be carried out using an amino-silane compound, i.e., 3-aminopropyl-triethoxysilane (APTES). It is an important silane coupling agent, which promotes interfacial behavior of nanomaterials. Whereas, hetero-functionalization of MWCNTs can be performed using APTES and cross-linking agent glutaraldehyde (GA). Key parameters for the immobilization of an enzyme on MWCNTs are selection of an efficient functionalizing agent, sonication of MWCNTs, enzyme load and enzyme coupling time. The optimal level of these factors is very important to obtain high specific activity and immobilization efficiency of the developed immobilized biocatalyst. Both homo- and hetero-functionalized MWCNTs can be used to develop an efficient immobilized biocatalyst having good operational stability. However, hetero-functionalized MWCNTs are more potent candidate for enzyme immobilization. The present methodology provides very efficient approach for enzyme immobilization on a versatile support to achieve high enzyme selectivity and operational stability for various industrial applications.