Target-induced reconstruction of Ru(bpy)32+-loaded gold nanocage for one-step highly sensitive detection of Hg2+

In this work, Ru(bpy) 3 2+ -loaded gold nanocage (AuNCs) (Ru–AuNCs) was prepared and found to display a distinct property of electrochemiluminescence (ECL) enhancement under mercury ions (Hg 2+ ) interaction. Based on this, we designed a screen-printed bipolar electrode-ECL (SPBPE-ECL) sensing platform by coupling with the thymine-Hg 2+ -thymine (T-Hg 2+ -T) binding pattern for one-step highly sensitive detection of Hg 2+ . This ECL sensor showed a wide linear detection range (0.75 – 850 μg L −1 ) and low detection limit (0.1290 μg L −1 ) toward Hg 2+ , with a one-step detection procedure and disposable feature, displaying potential applicability in the point-of-care-testing (POCT) of Hg 2+ in the environment. In addition, the Hg 2+ -mediated ECL signal enhancement mechanism of Ru–AuNCs was also investigated. It was confirmed that Hg 2+ interaction etched the cage structure of Ru–AuNCs, which sped up the release of more Ru(bpy) 3 2+ around the sensing electrode. Furthermore, Au–Hg alloy structure was formed on the surface of Ru–AuNCs, which also improved the ECL signal. This target-induced in-situ sensing material surface reconstruction strategy would provide a better design concept for the construction of ECL POCT sensor.