Target-Controlled Redox Reaction and Ru(II) Release of a Smart Metal-Organic Framework Nanomaterial for Highly Sensitive Ratiometric Homogeneous Electroanalysis of Cadmium(II)

Tingting Liu; Conglin Zhang; Shuhao Huo; Yifan Zhou; Yinhui Yi; Gangbing Zhu

doi:10.1021/acs.inorgchem.3c02760

Target-Controlled Redox Reaction and Ru(II) Release of a Smart Metal-Organic Framework Nanomaterial for Highly Sensitive Ratiometric Homogeneous Electroanalysis of Cadmium(II)

Inorg Chem. 2023 Oct 23;62(42):17425-17432. doi: 10.1021/acs.inorgchem.3c02760. Epub 2023 Oct 9.

Authors

Tingting Liu^{1

2}, Conglin Zhang¹, Shuhao Huo¹, Yifan Zhou¹, Yinhui Yi^{1

3

2

4

5}, Gangbing Zhu¹

Affiliations

¹ School of Emergency Management, School of the Environment and Safety Engineering, and Collaborative Innovation Center of Technology and Material of Water Treatment, Jiangsu University, Zhenjiang 212013, P. R. China.
² Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials, Xiamen University, Xiamen 361005, P.R. China.
³ Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Jiangnan University, Wuxi 214122, P. R. China.
⁴ State Environmental Protection Key Laboratory of Monitoring for Heavy Metal Pollutants, Changsha 410019, P.R. China.
⁵ The Key Laboratory of Spectroscopy Sensing, Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, P.R. China.

PMID: 37812810
DOI: 10.1021/acs.inorgchem.3c02760

Abstract

In this work, a highly sensitive ratiometric homogeneous electroanalysis (HEA) strategy of cadmium(II) (Cd²⁺) was proposed via a Cd²⁺-controlled redox reaction and Ru(bpy)₃²⁺ (Ru(II)) release from a smart metal-organic framework (MOF) nanomaterial. For achieving this purpose, Ru(II) was entrapped ingeniously into the pores of an MOF material (UiO-66-NH₂) and subsequently gated by the double-strand hybrids of a Cd²⁺-aptamer (Apt) and its complementary sequences (CP) to form a novel smart nanomaterial (denoted as Ru@UiO-66-NH₂); meanwhile, Fe(III) was selected as an additional probe present in electrolyte to facilitate the Ru(II) redox reaction: Fe(III) + Ru(II) → Fe(II) + Ru(III). Owing to the strong binding effect of the Cd²⁺ target to the specific Apt, the Apt-CP hybridization at Ru@UiO-66-NH₂ would be destroyed in the presence of Cd²⁺, and the related Apt was further induced away from the smart nanomaterial, leading to the opening of the gate and release of Ru(II). Meanwhile, the released Ru(II) was quickly oxidized chemically by Fe(III) to Ru(III). On the basis of the generated Ru(III) and consumed Fe(III), the ratio of the reduction currents between Ru(III) and Fe(III) exhibits an enhancement and it is dependent on the level of Cd²⁺; thus, a novel HEA strategy of Cd²⁺ was then designed. Under the optimal conditions, the HEA sensor shows a wide linearity ranging from 10.0 pM to 500.0 nM, and the achieved detection limit of Cd²⁺ is 3.3 pM. The as-designed ratiometric HEA strategy not only offers a unique idea to realize a simple and sensitive assay for Cd²⁺ but also possesses significant potential as an effective tool to be introduced for other target analysis just via altering the specific Apt.