Colorimetric detection of glutathione based on transverse overgrowth of high aspect ratio gold nanorods investigated by MCR-ALS

Abstract

In this paper, we present a simple platform for colorimetric detection of glutathione using gold nanorods (AR $ 6.5 AE 0.2) as a plasmonic sensor. The functional mechanism of the sensor is based on shifts of longitudinal plasmon resonance during selective transverse overgrowth induced by preferential binding of glutathione at the nanorod tips. Under the optimum conditions, a calibration curve showed two linear regimes at the range of 50 nM to 20 mM of glutathione with a detection limit as low as 40 nM. The nanosensor maintains relatively high selectivity for determination of glutathione in the presence of several other amino acids. However, cysteine at similar concentration levels strongly competes with glutathione for available binding sites, thereby interfering in the determination of glutathione. We employed multivariate curve resolution-alternating least square (MCR-ALS) to track the morphology variation of the nanorods and elucidate the kinetics of the overgrowth process in the presence of glutathione and cysteine.

Stimuli Responsive Molecular Exchange of Structure Directing Agents on Gold Nanobipyramids: Cancer Cell Detection and Synergistic Therapeutics

“…Among various nanoparticles, gold nanoparticles have previously been used as GSH detection. Exposure to GSH causes gold nanoparticle aggregation due to rapid exchange between existing surfactant on the surface of nanoparticles and excess GSH in the medium, leading to color change in colloidal solutions and absorption shifts. , Hence, we utilized newly designed gold nanoparticles, viz., AuNBPs to detect GSH at molecular level within cancer mimicked conditions. To test this, high concentrations of GSH (cancer cell interior condition GSH in mM range) were added to DMAB-AuNBPs in solution, altering the native reddish color of the solution progressively to essentially colorless over time (Figure a).…”

“…In this study, we have prepared AuNBPs followed by a seed-mediated method using sodium borohydride, a mild reducing agent for the reduction of chloroauric acid. − In brief, the reaction is carried out in the presence of citrate, which caps and stabilizes the seeds. Citrate also helps in twinning defects and polycrystallinity in the seeds which promote AuNBPs formation .…”

A “turn-on” fluorescent probe used for the specific recognition of intracellular GSH and its application in bioimaging

“…4,5 In particular, GSH is the most abundant intracellular thiol (1-10 mM) in mammalian and many prokaryotic cells, functioning as an essential endogenous antioxidant primarily involved in regulating cellular redox activities and preventing cell damage via scavenging free radicals and peroxides. 6,7 Aberrant levels of GSH are directly associated with numerous clinical diseases, including cancer, human immunodeciency virus (HIV), Alzheimer's, liver damage, leukocyte loss, cardiovascular disease and others. 8,9 Accordingly, developing efficient techniques for the detection of GSH under physiological conditions is of considerable signicance and has attracted a great deal of attention.…”