PH-Induced silver nanoprism etching-based multichannel colorimetric sensor array for ultrasensitive discrimination of thiols

Abstract

A multichannel colorimetric sensor array for detection of five thiols, including glutathione (GSH), cysteine (Cys), dimercaptosuccinic acid (DMSA), 3-mercaptopropionic acid (MPA) and dithiothreitol (DTT), is demonstrated in water and diluted fetal bovine serum based on the pH-induced silver nanoprism (AgNPR) etching strategy. The etching of AgNPRs by dissolved oxygen in the alkaline pH environment causes a blueshift of the localized surface plasmon resonance (LSPR) absorption. AgNPRs at three pH values (pH 11, pH 11.6, and pH 12) with different LSPR absorptions are selected as the sensing elements. The present sensor array shows a high sensitivity, and five thiols can be well distinguished at concentrations as low as 10 nM which is two to three orders of magnitude better than that of the reported sensor array. Notably, the identification of 16 unknown thiol samples with 100% accuracy is achieved. Additionally, this sensor array is able to discriminate individual thiols and their mixtures.