Experimental and computational investigation of a DNA-shielded 3D metal-organic framework for the prompt dual sensing of Ag+ and S2.

Shao-Lan Cai,Wen-Jun Duan,Ling-Yan Zhai,Nai-Han Huang,Cheng Fan,Ke-Yang Wu,Rong-Tian Li,Jin-Xiang Chen,Zi-Chuan Yang

doi:10.1039/c9ra02028d

Abstract

We herein report an efficient Ag+ and S2− dual sensing scenario by a three-dimensional (3D) Cu-based metal–organic framework [Cu(Cdcbp)(bpea)]n (MOF 1, H3CdcbpBr = 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 S2− in one pot, with detection limits of 3.8 nM (for Ag+) and 5.5 nM (for S2−), which are much more lower than the allowable Ag+ (0.5 μM) and S2− (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 S2− 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.

Highlights

Silver ions (Ag+) are ubiquitous and widely applied in various elds including biomedicine, antibacterial manufacturing, etc.[1]the biological accumulation of Ag+ raises serious concerns as a result of its relevance to multiple organ dysfunction syndrome, cytotoxicity, argyria and weakness of mitochondrial ability.[2]
Ag+ is accumulated via the water and food cycle, and a 0.5 mM concentration up-limit of Ag+ in drinking water is regulated by U.S Environmental Protection Agency (US EPA) and World Health Organization (WHO).[3]
Single crystal X-ray diffraction analysis revealed that metal–organic frameworks (MOFs) 1 crystallizes in the monoclinic space group C2/c and the asymmetric unit consists one [Cu(Cdcbp)(bpea)] molecule

Summary

Introduction

Silver ions (Ag+) are ubiquitous and widely applied in various elds including biomedicine, antibacterial manufacturing, etc.[1]the biological accumulation of Ag+ raises serious concerns as a result of its relevance to multiple organ dysfunction syndrome, cytotoxicity, argyria and weakness of mitochondrial ability.[2]. The MOF and P-DNA are associated through p– p stacking, hydrogen bonding, and electrostatic interactions, and thereby quenches the TAMRA uorescence of the latter (offstate) via a photo-induced electron transfer to eliminate the high background uorescence (Fig. 1b).[14] The formed MOF-

Results

Conclusion