Glucose Biosensor Based On Encapsulated Enzyme with Peptide Nanotubes

Application of bio-inspired nanostructures to enzymes can enhance the performance of enzymes and enzymatically facilitated systems. Peptide nanotubes (PNTs) are used to maintain enzyme activity that is susceptible to the enzyme orientation and surrounding conditions. The enzymes encapsulated inside a PNT may have higher thermal stability, long-term storage stability and resistance to denaturants compared to the free enzymes in a solution. PNT’s nanostructure has the environmental functionalities such as biocompatibility, large surface-to-volume ratio and robust backbone structure. Moreover, the unique properties of PNTs provide a possible prospect such as electrical conductivity. In this study, a nanostructure of the peptide nanotube was examined for possible use as a support material for enzyme encapsulation. A model enzyme, hydrogen peroxidase (HRP), was efficiently bound into the peptide nanotube. The catalytic activity of HRP encapsulated inside PNTs was examined in terms of thermal stability, long-term stability, and resistance to a denaturant. The results showed that the encapsulated HRP has a higher enzyme activity than the free HRP in a solution. Moreover, an amperometric biosensor was developed using a bi-enzyme system of glucose oxidase (GOx) and the encapsulated HRP into the PNTs to detect glucose. The results showed great potential of the encapsulation technique in the development of more stable biosensors without compromising the enzyme sensitivity. These results suggest that the encapsulation of enzyme inside a PNT can be used as a stabilization technique in biocatalyst and biosensor applications where retaining the enzyme activity is important.