LSPR Sensing of Molecular Biothiols Based on Noncoupled Gold Nanorods

Abstract

Au NRs protected with mPEG-SH molecules (mPEG-Au NRs) were demonstrated to be a promising platform for LSPR-based sensing of molecular biothiols in aqueous solution. Surface mPEG-SH molecules endow Au NRs with great stability and biocompatibility and no nonspecific adsorption of biomacromolecules. The LSPR band of mPEG-Au NRs displays a stability and linear response in the spectral shift with respect to a change in their surrounding refractive index with a sensitivity of 252 nm/RIU. The loose structure of mPEG-SH around the Au NRs offers free sites, thereby allowing molecular biothiols to bind onto the surfaces of Au NRs. The LSPR response and the sensitivity of Au NRs to biothiols such as GSH, Cys, Hcy, TGA, GSSG, and BSA were then studied.

Sensitivity‐enhancement methods for surface plasmon sensors

“…Taking both these aspects into account, Jah and Sharma [78] defined a performance parameter called intrinsic sensitivity S i , which is equivalent to the figure of merit (FOM) as it is commonly defined [68,130,132]. The parameter S i is directly proportional to the shift in resonance angle δ θ R and is inversely proportional to the average FWHM δ θ HM of two SPR curves (see Fig.…”

“…4.3 within the framework of extraordinary optical transmission (EOT) sensors. Other novel nanostructures were widely investigated and presented in the last few years as a high-sensitivity LSPR devices such as Au nanoparticles and multiwalled carbon nanotubes with sensitivity of about 5.6 times greater than Au NPs on a glass chip [128], aligned gold nanotube arrays [129], Au nanorods protected with mPEG-SH molecules as LSPR-based sensors of molecular biothiols [130]. Metamaterials-based sensors composed of nanorods with spectral sensitivity of 30 000 nm/RIU and a large probe depth up to 500 nm [131], phase-sensitive SPR biosensors with the use of gold nanorods as powerful amplification labels [132].…”

PAA‐Derived Gold Nanorods for Cellular Targeting and Photothermal Therapy

“…A common example is the use of thiolated bifunctional small molecules such as mercaptopropionic acid and/or mercaptohexanoic acid and other homofunctionalized thiol molecules [e.g. poly(ethylene glycol) (PEG) thiols] chemisorbed on the nanorod surfaces [8] to displace CTAB from the surface. While thiolated nanorods have good colloidal stability in buffered solutions, [9] they are prone to detach from the particle surface in the presence of other thiols, or during chromatographic purification steps.…”

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

“…S7, a good linear relationship of (F Cys − F blank )/F blank values against Cys concentrations was displayed in the range from 20 to 1000 nM with RSD between 0.8% and 10.8%. The limits of detection for GSH and Cys were attained of 10 nM and 20 nM, respectively, lower than common colorimetric methods [22,24,27]. These results demonstrated the fluorescence off-on sensing strategy based on place-substitution could highly sensitively and highly accurately quantify the 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.…”