Fast, sensitive and selective colorimetric gold bioassay for dopamine detection.

Colorimetric detection of dopamine has the advantage of simplicity in operation and instrumentation. Herein, a highly sensitive and selective colorimetric biosensor with fast response has been developed by using 4'-aminobenzo-18-crown-6 (ABCE) and 4-mercaptophenyl boronic acid (MPBA) modified Au nanoparticles. The modified probe shows an excellent detection limit of 6.0 nM of dopamine at a S/N of 2.01 and about 46 nM at a S/N of 3 within microseconds response. It exhibits excellent detection selectivity even in 1000-fold excess of many different interferents like metal ions, uric acid and ascorbic acid. All these may make it fulfill the requirements for in vivo analysis.