Coupling gold nanoparticles to silica nanoparticles through disulfide bonds for glutathione detection

Abstract

Advances in the controlled assembly of nanoscale building blocks have resulted in functional devices which can find applications in electronics, biomedical imaging, drug delivery etc. In this study, novel covalent nanohybrid materials based upon [Ru(bpy)3](2+)-doped silica nanoparticles (SiNPs) and gold nanoparticles (AuNPs), which could be conditioned as OFF-ON probes for glutathione (GSH) detection, were designed and assembled in sequence, with the disulfide bonds as the bridging elements. The structural and optical properties of the nanohybrid architectures were characterized using transmission electron microscopy, UV-vis spectroscopy and fluorescence spectroscopy, respectively. Zeta potential measurements, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were employed to monitor the reaction processes of the SiNPs-S-S-COOH and SiNPs-S-S-AuNPs synthesis. It was found that the covalent nanohybrid architectures were fluorescently dark (OFF state), indicating that SiNPs were effectively quenched by AuNPs. The fluorescence of the OFF-ON probe was resumed (ON state) when the bridge of the disulfide bond was cleaved by reducing reagents such as GSH. This work provides a new platform and strategy for GSH detection using covalent nanohybrid materials.

Rapid determination of dopamine in human plasma using a gold nanoparticle-based dual-mode sensing system

“…1) consists of fluorophore-labeled dopamine-binding aptamers and AuNPs. It is well known that AuNPs possess distancedependent optical properties and have a superior quenching efficiency [33][34][35][36][37]. The addition of aptamers into AuNPs colloid solution would prevent the AuNPs from aggregation in the high-salt solution while the close distance between AuNPs and fluorophore conjugated on the aptamers leads to the fluorescence quenching.…”

“…In the colorimetric mode, dopamine could specifically bind to the aptamers thus changing the stability of the AuNPs in solution, resulting in the color change of AuNPs solution. In the fluorometric mode, a fluorescence resonance energy transfer system (FRET) is developed using the fluorophore labeled aptamers as donors and AuNPs as acceptors [33][34][35][36][37]. The dual-mode sensing system has high specificity towards dopamine with the detection limit of as low as 78.7 nM.…”

Novel Gallium Polyoxometalate/Nano‐Gold Hybrid Material Supported on Nano‐sized Silica for Mild Cyclohexene Oxidation Using Molecular Oxygen

“…The biggest peak at 1070 cm −1 relates to the stretching vibrational bands of the Si–O–Si or O–Si–O functional group, which is not present in the spectra of GaW 11 ‐APTES@SiO 2. Vibrational modes of CH 2 group are observed at 871 cm −1 , whereas the band with peak at 971 cm −1 is assigned to Si–O–Si stretching modes . Small peaks at about 1505 cm −1 correspond to bending vibrations of the C–H bond.…”

Disulfide-Bridged Cleavable PEGylation in Polymeric Nanomedicine for Controlled Therapeutic Delivery

“…The cross-linker is typically employed with the S-S moiety. These include cystamine dihydrochloride [22,25,26,43,[50][51][52][53][54], 2,2-dithiodiethanol (DTDE) [55,56], 3,3′-dithiodipropionic acid (DPA) [57][58][59][60], N,N′-cystaminebisacrylamide [61], 2,2′-dithiodipyridine [27,44,62], 2-(pyridyldithio)-propionic acid [63], cystamine bisacrylamide [64], N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) [65,66] and sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido) hexanoate (sulfo-LC-SPDP) [67]. Alternative approaches involve conjugation of the thiol group (-SH) with PEG or other polymers, and subsequent oxidation of -SH with oxidants such as N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) [68] and pyridyl disulfide carbonate [69] in order to form the S-S bond.…”