1.
A Label-Free Immunosensor Based on Graphene Oxide/Fe3O4/Prussian Blue Nanocomposites for the Electrochemical Determination of HBsAg.
Wei, S, Xiao, H, Cao, L, Chen, Z
Biosensors. 2020;(3)
Abstract
In this article, a highly sensitive label-free immunosensor based on a graphene oxide (GO)/Fe3O4/Prussian blue (PB) nanocomposite modified electrode was developed for the determination of human hepatitis B surface antigen (HBsAg). In this electrochemical immunoassay system, PB was used as a redox probe, while GO/Fe3O4/PB nanocomposites and AuNPs were prepared and coated on screen-printed electrodes to enhance the detection sensitivity and to immobilize the hepatitis B surface antibody (HBsAb). The immunosensor was fabricated based on the principle that the decrease in peak currents of PB is proportional to the concentration of HBsAg captured on the modified immunosensor. The experimental results revealed that the immunosensor exhibited a sensitive response to HBsAg in the range of 0.5 pg·mL-1 to 200 ng·mL-1, and with a low detection limit of 0.166 pg·mL-1 (S/N = 3). Furthermore, the proposed immunosensor was used to detect several clinical serum samples with acceptable results, and it also showed good reproducibility, selectivity and stability, which may have a promising potential application in clinical immunoassays.
2.
Dithiocarbamate-capped silver nanoparticles as a resonance light scattering probe for simultaneous detection of lead(II) ions and cysteine.
Cao, H, Wei, M, Chen, Z, Huang, Y
The Analyst. 2013;(8):2420-6
Abstract
We investigated the suitability of dithiocarbamate (DTC) capped Ag nanoparticles (NPs) as resonance light scattering (RLS) probes for the simultaneous sensing of Pb(2+) and cysteine. The DTC capping ligands are generated by a very simple in situ method through reaction of carbon disulfide with diethanolamine as primary precursor molecules under ultrasonic irradiation. This strategy was based on the fact that Pb(2+) could induce the aggregation of DTC-Ag NPs due to the strong metal affinity of DTC along with an enhanced RLS signal. After optimizing some experimental conditions (including the pH value of the solution, concentration of DTC-Ag NPs, and ion strength), a very simple and facile sensing system has been developed for the detection of Pb(2+) in water based on RLS technology. The proposed system promises excellent selectivity, a wide linear response range and high sensitivity for Pb(2+). The linear response range for Pb(2+) was from 0.01 μM to 60 μM. The limit of detection (S/N = 3σ) for Pb(2+) was as low as 4 nM. The proposed method was successfully used to detect Pb(2+) in river and tap water samples, indicating the potential of this new, sensitive and selective method in water quality monitoring. Meanwhile, due to the strong binding preference of cysteine toward Pb(2+) by the formation of Pb(2+)-S bonds, Pb(2+) was removed from the surfaces of the DTC-Ag NPs, leading to redispersion of DTC-Ag NPs, along with a decreased RLS signal. The possibility of the proposed system for the sensing of cysteine was also investigated.