Naked-eye detection of cysteine/homocysteine through silver nano-resonators and specific identification of homocysteine through nanoresonator–thiosulphate conjugate

Abstract

This study presents simultaneous colorimetric detection of two very similar amino thiols viz. cysteine and homocysteine at their micro and sub-micromolar levels, respectively, through the aggregation of citrate capped silver nanoparticles. A rare kind of categorical naked-eye detection of homocysteine over cysteine was accomplished through the conjugation of these AgNPs with thiosulphate. The UV-Vis and SERS characteristics of these AgNPs were also more prominent with homocysteine compared to cysteine. The quantification of cysteine was performed in a pharmaceutic sample with an accuracy of 89 ± 5%.