Gold-nanoparticle-based biosensors for detection of enzyme activity

Optimal enzyme activity is essential for maintenance of physiological homeostasis. A variety of both non-genetic and genetic disruptions can excessively activate or silence intrinsic enzyme activities, with pathological outcomes. Many pharmacological agents are activators and inhibitors of enzymes. It is essential, therefore, in the development of drugs as enzyme activators and inhibitors, that enzyme activities be accurately measured under physiological and pathological conditions. Different biochemical assays have been developed for this purpose, some of which are based on nanostructured materials. This review focuses on gold nanoparticle (GNP)-based structures for the sensing and measurement of enzyme activities in biological specimens. Here we provide an overview and critical analysis of such assays, identify their advantages and limitations, and discuss interesting features of GNPs to be exploited for future applications in pharmacology.