Application of Cys A@AuNPs supported amino acids towards rapid and selective identification of Hg(II) and Cu(II) ions in aqueous solution: An innovative microfluidic paper-based (μPADs) colorimetric sensing platform

In this study, an innovative methods was proposed for the synthesis of cysteamine@gold nanoparticle (CysA@AuNPs) using one step protocol. Also, application of CysA@AuNPs for the sensitive recognition of Hg (II) and Cu (II) in aqueous media was investigated using optical techniques. This research work explains the development of a lightweight stamp for manufacturing of a novel microfluidic paper-based analytical device (μPADs), as a simple colorimetric sensor for selective recognition of Hg2+ and Cu2+ within the other metal ions (Fe(III), Mn(II), Zr(IV), Ba(II), Mg(II), Sr(II), As(III), B(III), Al(III), V(III), K(I), Na(I), Mo(II), Co(II), Zn(II), Sn(II), Se(IV), Cr(III), Bi(III)) in aqueous, and human biofluids. CysA@AuNPs supported amino acids were used as the ion detection probs. The specific colorimetric response of Hg2+ and Cu2+ amongst the other ions through the innovative sensor allows naked-eye discrimination of the mercury and copper metal ions in this work with excellent selectivity in the presence of cysteine, and methionine. The results revealed our new strategy (μPADs) for the colorimetric recognition of mercury and copper ions, in both urine and aqueous samples, is selective, simple, fast, sensitive, quantitative, cost-effective, and eco-friendly, which can be detected by naked eye through color alternation with LLOQ of 0.001 ppm for Hg2+, and 0.02 ppm for Cu2+ with admirable stability. The low instrumental needs of the stamp, and disposability of μPADs enable the application of the suggested paper-based device for the commercial diagnostics biosensor.