Highly selective and sensitive detection of glutathione based on anti-aggregation of gold nanoparticles via pH regulation

Abstract Glutathione (GSH) plays a key role in biological systems and serves many cellular functions. Since biothiols all incorporate thiol, carboxylic and amino groups, discriminative detection of GSH over cysteine (Cys) and homocysteine (Hcy) is still challenging. Both Cys and Hcy can induce aggregation of AuNPs via the formation of zwitterionic networks, which is different from GSH. GSH induced aggregation of AuNPs by the hydrogen bonding between the carboxylic groups when pH 650 nm /A 520 nm and the GSH concentration is obtained (R 2  = 0.998) with a detection limit of 12.0 nM.