Research on modifying the Au surface by thiol compound for biosensor application

Abstract

In cantilever-based biosensor, Au surface plays two essential roles:  as a surface to reflect laser beam and as a surface to be modified and thus functionalize the sensor. In this paper, we researched on modifying the Au surface by cysteamine and glutaraldehyde to make it reactive toward amine substances. Cysteamine concentration, cysteamine treatment time and glutaraldehyde treatment time were investigated to find optimal values. The data of chromogenic reaction catalyzed by horseradish peroxidase (HRP) and the data of water contact angle measurement were combined to find the optimal values. The results showed that the modification with 5 mM cysteamine in ethanol for 16 h and glutaraldehyde for 1 h would create the Au surface which can react optimally with amine substances.