A sequential artificial light-harvesting system based on a metallacycle for sensitive detection of biothiols†

The aberrant alterations of biothiols (cysteine, homocysteine and glutathione) are closely linked to the state of human health, and therefore the development of a reliable technique for accurately identifying biothiols is crucial for disease screening and diagnosis. Herein, a cascaded artificial light-harvesting system (ALHS) was constructed to detect biothiols with high sensitivity and specificity. In the ALHS, AIE-active MPt1 was used as the energy donor, ESY and SR101 were selected as the first and second energy acceptors, respectively. The MPt1–ESY–SR101 assembly demonstrated an orange red to yellow fluorescence color change and a noticeable decline in fluorescence intensity at 606 nm in the presence of biothiols. The detection limits of the MPt1–ESY–SR101 system for Cys, GSH and Hcy were 3.09 × 10⁻⁸ M, 5.02 × 10⁻⁸ M and 5.05 × 10⁻⁸ M, respectively. Moreover, total biothiols in serum samples from patients with coronary heart disease and healthy individuals have been accurately quantified using the MPt1–ESY–SR101 system.