Analysis of antifreeze protein activity using colorimetric gold nanosensors

Abstract

High activity and long stability of antifreeze proteins (AFPs), also known as ice-binding proteins (IBPs), are necessary for exerting their physiological functions in biotechnology and cryomedicine. Here we report a simple analysis of antifreeze protein activity and stability based on self-Assembly of gold nanoparticles (AuNPs) via freezing and thawing cycles. While the mercaptosuccinic acid-capped AuNP (MSA-AuNP) was easily self-Assembled after a freezing/thawing cycle, due to the mechanical attack of ice crystal on the MSA-AuNP surface, the presence of AFP impeded the self-Assembly of MSA-AuNP via the interaction of AFP with ice crystals via freezing and thawing cycles, which led to a strong color in the MSA-AuNP solution. As a result, the aggregation parameter (E520/E650) of MSA-AuNP showed the rapid detection of both activity and stability of AFPs. We suggest that our newly developed method is very suitable for measuring antifreeze activity and stability in a simple and rapid manner with reliable quantification.