Experimental and computational investigation of a DNA-shielded 3D metal-organic framework for the prompt dual sensing of Ag + and S 2 .

We herein report an efficient Ag + and S 2- dual sensing scenario by a three-dimensional (3D) Cu-based metal-organic framework [Cu(Cdcbp)(bpea)] n (MOF 1, H 3 CdcbpBr = 3-carboxyl-(3,5-dicarboxybenzyl)-pyridinium bromide, bpea = 1,2-di(4-pyridinyl)ethane) shielded with a 5-carboxytetramethylrhodamine (TAMRA)-labeled C-rich single-stranded DNA (ss-probe DNA, P-DNA) as a fluorescent probe. The formed MOF-DNA probe, denoted as P-DNA@1, is able to sequentially detect Ag + and S 2- in one pot, with detection limits of 3.8 nM (for Ag + ) and 5.5 nM (for S 2- ), which are much more lower than the allowable Ag + (0.5 μM) and S 2- (0.6 μM) concentration in drinking water as regulated by World Health Organization (WHO). The detection method has been successfully applied to sense Ag + and S 2- in domestic, lake, and mineral water with satisfactory recoveries ranging from 98.2 to 107.3%. The detection mechanism was further confirmed by molecular simulation studies.