Authors
Chen Ma, Yida Zhang, Shuai Mu, Yuan Zhang, Shuoyun Wei, Quanfang Li, Shufang Ren
Published in
Mikrochimica acta. Volume 193. Issue 11. Oct 07, 2026. Epub Oct 07, 2026.
Abstract
A novel Hg2+ sensing strategy has been developed based on a Mn-Au hybrid nanozyme with prominent oxidase-like activity and an aptamer-controlled catalytic switching mechanism. First, a Mn-Au hybrid nanozyme (MnAuNPs) with a distinctive "fried-egg-like" core-shell morphology was synthesized, which exhibited remarkable oxidase-like activity and rapidly oxidized 3,3',5,5'-tetramethylbenzidine (TMB) into the characteristic blue product (OxTMB) without H2O2. The Hg2+-specific aptamer can adsorb onto the surface of MnAuNPs through electrostatic and Mn-phosphate coordination interactions, which blocks the catalytic sites and markedly suppresses the oxidase-like activity. In the presence of Hg2+, the specific T-Hg2+-T coordination triggers the detachment of the aptamer from the MnAuNPs surface, thereby restoring oxidase-like activity and inducing distinct color and absorbance change. Accordingly, an effective colorimetric platform for Hg2+ detection was developed, exhibiting a linear response over the range of 1.0-50 μM with a limit of detection (LOD) of 0.32 μM. In parallel, a paper-based smartphone-assisted sensing platform was developed, enabling on-site Hg2+ detection in the range of 5.0-50 μM with LOD of 5.0 μM. Through the colorimetric and smartphone-assisted method, accurate quantification of Hg2+ in the Yellow River water and wastewater samples were achieved with the results in good agreement with those obtained by ICP-OES. Overall, this work establishes a simple and portable H2O2-free colorimetric sensing strategy based on Hg2+-induced catalytic switching for environmental Hg2+ monitoring.
PMID:
42842034
Bibliographic data and abstract were imported from PubMed on 08 Oct 2026.
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