colorimetric and fiber optic sensing of cysteine using green synthesized gold nanoparticles

In the present study, simple green synthesis of stable gold nanoparticles (green aunps) in an aqueous medium using flower extract of acmella oleracea is reported. in addition, colorimetric sensing property of the green aunps towards cysteine was explored. nanoparticles were characterized using uv-visible spectroscopy, xrd, ftir and hr-tem analysis, confirming the formation of stable aunps with an average size of 5 nm. further, an lspr-based fiber optic sensor using green aunps as a sensing material was developed. the fabricated fiber optic sensor is based on the change in lspr absorption intensity. lspr of the gold nanoparticles changes with interactions in the near environment of the gold surface. the results suggest that colorimetric and fiber optic sensor could be used as a cost-effective sensing system for cysteine detection.