A simple assay for direct visual and colorimetric sensing application of cysteamine using Au@Ag core-shell nanoparticles

User-friendly and ultra-stable all-inclusive gold tablets for cysteamine detection

“…To demonstrate the practical application of the pAuNP-Tablet sensor under real-life conditions, the detection of cysteamine was also conducted in real human serum samples taken from cystinosis patients (pH 6.5–7.0). Furthermore, a spiking test was conducted in actual human serum, and the method was validated by calculating the percent recovery (% R) using the formula reported by Sasikumar et al : 44 Rate of recovery (%) = (amount of cysteamine found (μM))/(amount of cysteamine added (μM)) × 100%.…”

Use of metal nanoparticles for preconcentration and analysis of biological thiols

“…The second step involved reduction of Ag(I) and formation of shells, which was indicated by a color change from red to burnt orange. The absorption spectra of Au@Ag core-shell NPs indicated two resonance peaks corresponding to Au and Ag around 500 and 400 nm, respectively [60,61]. Protein-stabilized Au@Ag NPs were used for fluorescence detection of cysteine (Cys) and homocysteine (Hcys).…”

“…A simple method based on aggregation of label-free AuNPs and a related color change of the solution as well as change of the absorption spectra was used for the determination of CA with nanomolar sensitivity [95]. A very low LOD (0.33 nM) was achieved for CA using Au@Ag core-shell NPs [61]. The aggregation of these NPs caused the color change from burnt orange to colorless.…”

Colorimetric sensing of glucose and GSH using core–shell Cu/Au nanoparticles with peroxidase mimicking activity

“…In order to further improve the catalytic properties and applications of gold-based nanomaterials, their composites have been widely studied, such as Au@TiO 2 yolk–shell structure, 15 ZnFe 2 O 4 @Au, 16 Cu@Au NPs 5,6 and Au@Ag. 17 Besides, as a cheap alternative to precious metals, copper-based semiconductor nanomaterials have been widely studied because of their well-defined shape characteristics 18 and peroxidase activity, such as Cu NCs 19 and CuS NCs. 20 Therefore, the excellent properties of gold and copper were combined for the construction of sensors to be widely studied, such as the detection of chromium ( iii ) based on Cu/Au NCs, 21 the detection of lysozyme 6 and cancer cells 7 based on the special reaction of Cu/Au NPs to iodine and the electrochemical detection of Escherichia coli based on Cu/Au NPs.…”