Aptamer conjugated silver nanoparticles for the colorimetric detection of arsenic ions using response surface methodology

In this study, aptamer conjugated silver nanoparticles (Apt-SNPs) were synthesized and studied for colorimetric sensing of As(III) ions in solution. As(III) ions specifically interact with Apt-SNPs to form As(III)-Apt-SNPs and cause a remarkable decrease in the absorbance peak of silver nanoparticles at 403 nm, which enables the determination of As(III) with high selectivity and sensitivity. A three-factor, central composite design (CCD) optimization method combined with response surface methodology (RSM) was employed to maximize the efficiency of arsenic detection. The significance of the independent variables and their interactions were tested using the analysis of variance (ANOVA). The linear dynamic range of the colorimetric Apt-SNP based optical sensor covered a large variation of As(III) concentration from 50 to 700 mu g L-1 and a detection limit of 6 mu g L-1 was obtained. Moreover, this assay was able to detect As(III) ions with high sensitivity and revealed to have remarkable potential applications.