Decreased resonance light scattering of citrate-stabilized gold nanoparticles by chemisorption of mercaptoacetic acid

A dual-mode method for detection of miRNA based on the photoluminescence and resonance light scattering

MicroRNAs (miRNAs) hold potential as useful biomarkers for early diagnosis and evaluation of diverse cancers, but their low abundance and short length make the detection of miRNAs face low sensitivity and accuracy. Herein, a photoluminescence (PL)-resonance light scattering (RLS) dual-mode method was developed for the sensitive and accurate detection of miRNA-141 using CdTe quantum dots (QDs) and Au nanoparticles. The presence of miRNA-141 induced PL quenching and RLS increasing. The limit of detection (LOD) was as low as 3.7 fM, and the miRNA-141 was detected linearly in a range from 10 fM to 10 nM. The dual signals generated no mutual interference and were detected using the same spectrophotometer, allowing for mutual validation to ensure the accuracy and reliability of the detection results. This study proposes valuable references for constructing dual-mode detection methods.

Antiviral Effect of Nonfunctionalized Gold Nanoparticles against Herpes Simplex Virus Type-1 (HSV-1) and Possible Contribution of Near-Field Interaction Mechanism

The antiviral activity of nonfunctionalized gold nanoparticles (AuNPs) against herpes simplex virus type-1 (HSV-1) in vitro was revealed in this study. We found that AuNPs are capable of reducing the cytopathic effect (CPE) of HSV-1 in Vero cells in a dose- and time-dependent manner when used in pretreatment mode. The demonstrated antiviral activity was within the nontoxic concentration range of AuNPs. Interestingly, we noted that nanoparticles with smaller sizes reduced the CPE of HSV-1 more effectively than larger ones. The observed phenomenon can be tentatively explained by the near-field action of nanoparticles at the virus envelope. These results show that AuNPs can be considered as potential candidates for the treatment of HSV-1 infections.

Trace mercury ion determination based on the highly selective redox reaction between stannous ion and mercury ion enhanced by gold nanoparticles

A novel resonance light scattering (RLS) spectrometric method for mercury ions (Hg(2+)) determination has been established in this article. Mercury (Hg) nanoparticle formed from the highly selective redox reaction between citrate-stabilized stannous ions (Sn(2+)) and Hg(2+). As a result, the RLS intensities of the system can be enhanced and it can be sensitized in the presence of very little amount of gold nanoparticles (AuNPs). According to this phenomenon, trace Hg(2+) in real water sample has been determined directly by RLS spectrometry. It has been found that the enhanced RLS intensities (ΔI(RLS)) characterized at 395 nm are proportional to the concentration of Hg(2+) in the range of 0.1-30 μmol L(-1) with a detection limit (3σ) of 0.051 μmol L(-1). The method described herein has good sensitivity, selectivity, and without complicated sample pretreatment. Moreover, the feasibility for the analysis of Hg(2+) in a wastewater sample was identified with a good recovery (100.2-106.3%).