Selective and sensitive detection of l-Cysteine via fluorometric assay using gold nanoparticles and Rhodamine B in aqueous medium

Publication date: Available online 4 June 2019Source: Materials Chemistry and PhysicsAuthor(s): Pradip Maiti, Tanmoy Singha, Utsav Chakraborty, Sannak Dutta Roy, Parimal Karmakar, Bapi Dey, Syed Arshad Hussain, Sharmistha Paul, Pabitra Kumar PaulAbstractAn assay method based on fluorometric and colorimetric change was developed for selective sensing of important thiol containing amino acid l-Cysteine (L-Cys) by using gold nanoparticles (Au NPs) and Rhodamine B (RhB) in aqueous environment. This fluorometric assay is basically relies on the competitive binding between RhB and Au NPs via electrostatic interaction as well as strong thiol(-SH)-Au NPs bonding via chemisorption. Citrate stabilized Au NPs (diameter ∼27 nm) was synthesized by soft chemical method and characterized by UV–Vis absorption spectroscopy and Transmission electron microscopic (TEM) techniques. The change in non-radiative energy transfer between RhB and Au NPs are responsible for the observed drastic fluorescence quenching of RhB via FRET process. The recovery of fluorescence from the assay solution of RhB/Au NPs after addition of L-Cys was found linear over the concentration range 0.01 μM–1000 μM with experimental limit of detection (LOD) of 0.01 μM. The selective interaction of L-Cys with the mixed solution of RhB/Au NPs was reflected by the color change from wine to bluish-black of the final solution. The proposed fluorometric assay method accompanied with the observed colorimetric change ...
Source: Materials Chemistry and Physics - Category: Materials Science Source Type: research