Accelerating the peroxidase- and glucose oxidase-like activity of Au nanoparticles by seeded growth strategy and their applications for colorimetric detection of dopamine and glucose

The peroxidase (POD)- and glucose oxidase (GOx)-like activity of Au nanoparticles (AuNPs) is very low compared to that of natural enzymes, which greatly limits their application in biological field. Herein, we found that the enlargement of AuNPs by dopamine-mediated seeded growth strategy could significantly accelerate the POD- and GOx-like activity of AuNPs. The increase of the dual enzyme-like activities may be ascribed to the formation of branched Au superstructures in the seeded growth process. With the enhancement of dual enzyme-like activities of AuNPs, a sensitive and selective colorimetric detection of dopamine and glucose can be achieved respectively. This work is expected to provide a general method to synthesize other metal-based nanomaterials with branched superstructres and extend its application in areas such as medical diagnosis and therapy. • The negligible glucose oxidase-like activity and low peroxidase-like activity of Au nanoparticles were greatly enhanced by seeded growth strategy. • With the enhancement of dual enzyme-like activities of Au nanoparticles, a sensitive colorimetric detection of dopamine and glucose were achieved respectively. • The formation of branched Au superstrctures in the seeded growth process was considered to be a contributing factor to the increase of dual-enzyme mimetic activities of Au nanoparticles.