Disulfide-Linked, Gold Nanoparticle Based Reagent for Detecting Small Molecular Weight Thiols

Abstract

Disulfide-linked gold nanoparticles (AuNP) were synthesized by reacting dithiobis[succinimidylpropionate] (DSP) coated nanoparticles with glutathione disulfide. AuNP-cross-linking was monitored by the red shift and broadening of the AuNP's localized surface plasmon absorption resonance (LSPR) spectrum. The exposure of the disulfide-linked AuNPs to a variety of free thiols with systematically varying molecular weight revealed a AuNP-disulfide stability to reduction by thiols up to a critical molecular weight, M(c), of >300 Da thus making the disulfide-linked AuNP the first reagent that can discriminate thiols based on their size.

Utilization of unmodified gold nanoparticles in colorimetric detection

“…HPLC, electrochemistry and fluorescence have been developed to detect cysteine. These methods, however, are restricted by either complicated instrumentation or tedious operating procedures [92,93]. DNA-AuNP conjugates have been applied as a col- orimetric sensor for cysteine and achieved a very low limit of detection [42].…”

Ultrasensitive visual detection of DNA with tunable dynamic range by using unmodified gold nanoparticles and target catalyzed hairpin assembly amplification

“…The notable benefit of the second strategy was avoiding the covalent functionalization of AuNPs (Kanjanawarut and Su, 2009). A series of novel assay methods have been developed by unmodified AuNPs based colorimetric assay for detection of low concentrations of metal ions, small molecules, and biomacromolecules (Wang et al, 2008a(Wang et al, , 2008bZhang et al, 2008;Ai et al, 2009;Durocher et al, 2009;Wei et al, 2007). Recently, Plaxco and co-workers have proved the versatility of an AuNPs based colorimetric strategy to the specific and convenient detection of multiple targets including inorganic ions, small molecules, and proteins (Xia et al, 2010).…”

FITC functionalized magnetic core–shell Fe3O4/Ag hybrid nanoparticle for selective determination of molecular biothiols

“…In recent years, a great amount of interesting studies have focused on the determination and sensing of biothiols. Various analytical methods including high-performance liquid chromatography [10,11], capillary electrophoresis [12,13], mass spectrometry [14], chemiluminescence [15,16], electrochemistry assay [17,18], fluorimetry [19][20][21], and nanoparticles-based colorimetric sensing strategy [22][23][24][25][26][27] for biothiols have been developed. Among these methods, fluorescent probes and gold-nanoparticle-based colorimetric sensing gradually stand out in the rapid, sensitive, and selective determination of biothiols.…”

“…Yet, in most of the reported fluorescent methods, organic solvents are required to be introduced into the system to increase the solubility of fluorescent dyes [19][20][21]. As a type of recently developed biothiol sensor, gold-nanoparticlebased colorimetric sensing in general involves the aggregation, coupling, or assembly of gold nanospheres [22,23] and nanorods [24,25]. The dynamic process of nanoparticles assembly is strongly sensitive to the surrounding environment which should be carefully controlled in order to obtain reproducible assemblies.…”