Nanomaterial sensors for selective detection of biothiol compounds

Abstract

Novel nanomaterial sensors have been designed two different strategies of sensing approach. The first sensing system, the aggregation nanomicelles (TSC and TSD) were synthesized for GSH sensing based on disulfide-cleavaged trigger in the micelle. The result showed a large quenching fluorescent intensity around 587 nm and 528 nm corresponding to TSC and TSD, respectively, upon the addition of GSH in 2.5% DMSO/PBS at pH 6. Additionally, the benefit of TSD is utility for the distance-based fluorescence detection of 3D paper analytical device (3D-µPAD) for the detection of GSH.

Apart from GQDs sensors base, we demonstrated the utility and board applicability of GQDs/AuNPs nanohybrid with measurements of Cysteine (Cys) and Lysine (Lys) using UV-Visible and fluorescent spectroscopy, respectively. For Cys sensing approach, the Cys enable to induce the self-aggregation of GQDs/AuNPs resulting in the color change from red to blue and red shift from 525 nm to 645 nm. On the other hand, Lys exhibited the fluorescence recovery at 450 nm belonging to emission band of GQDs. This is indicative of the displacement of Lys on AuNPs and releasing free GQDs in the solution. This sensor provided a high selectivity toward Cys and Lys with LOD of 5.88 µM and 16.14 µM, respectively. Furthermore, GQDs/AuNPs offered an efficient quantitative determination of Cys in urine samples and Lys in milk samples with real time analysis and highly specific detection.