Evaluation of enzyme immobilization strategies on biosensor performance

Biosensor efficiency is highly dependent on the effective integration of biological entities with materials and sensing technology, besides the enzyme loading capacity of the material. Variability in critical parameters governing biosensor efficiency poses difficulty in the fair evaluation of reported literature related to diverse methods and materials for enzyme immobilization. Recent advances in nanotechnology have led to a comparison of traditional materials with nanomaterials for the immobilization of biocatalysts. The present study shows that enzyme immobilization is optimum in covalently bound enzyme, while the 3-D conformation of the enzyme is preserved through optimum curvature of nanoparticles. Further, the shape and approachability of nanostructures to the enzyme active center facilitate faster electron transfer for efficient electrochemical biosensing. The Gox-AuNPs modeified gold electrode showed 1.7 times higher current response and greater senstivity 22.42 pA mM-1 cm2 than Gox-Fe3O4NPs with senstivity 14.3 pA mM-1 cm-2 . After 60 days of storage at 25 °C the Gox-AuNPs retained 73% of its initial response whereas Gox- Fe3O4NPs retained 56%, indicating improved storage and enzymatic stability.