Fe(III)-based metal–organic framework-derived core–shell nanostructure: Sensitive electrochemical platform for high trace determination of heavy metal ions

Publication date: 15 August 2017
Source:Biosensors and Bioelectronics, Volume 94
Author(s): Zhihong Zhang, Hongfei Ji, Yingpan Song, Shuai Zhang, Minghua Wang, Changchang Jia, Jia-Yue Tian, Linghao He, Xiaojing Zhang, Chun-Sen Liu
A new core–shell nanostructured composite composed of Fe(III)-based metal–organic framework (Fe-MOF) and mesoporous Fe3O4@C nanocapsules (denoted as Fe-MOF@mFe3O4@mC) was synthesized and developed as a platform for determining trace heavy metal ions in aqueous solution. Herein, the mFe3O4@mC nanocapsules were prepared by calcining the hollow Fe3O4@C that was obtained using the SiO2 nanoparticles as the template, followed by composing the Fe-MOF. The Fe-MOF@mFe3O4@mC nanocomposite demonstrated excellent electrochemical activity, water stability and high specific surface area, consequently resulting in the strong biobinding with heavy-metal-ion-targeted aptamer strands. Furthermore, by combining the conformational transition interaction, which is caused by the formation of the G-quadruplex between a single-stranded aptamer and high adsorbed amounts of heavy metal ions, the developed aptasensor exhibited a good linear relationship with the logarithm of heavy metal ion (Pb²⁺ and As³⁺) concentration over the broad range from 0.01 to 10.0nM. The detection limits were estimated to be 2.27 and 6.73 pM toward detecting Pb²⁺ and As³⁺, respectively. The proposed aptasensor showed good regenerability, excellent selectivity, and acceptable reproducibility, suggesting promising applications in environment monitoring and biomedical fields.



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