In Situ Electrodeposited Synthesis of Electrochemiluminescent Ag Nanoclusters as Signal Probe for Ultrasensitive Detection of Cyclin-D1 from Cancer Cells

Metal nanoclusters (NCs) as a new type of electrochemiluminescence (ECL) nanomaterials have attracted great attention, but their applications are limited due to relatively low luminescent efficiency and a complex preparation process. Herein, an ultrasensitive ECL biosensor for the detection of Cyclin-D1 (CCND1) was designed by utilizing in situ electrogenerated silver nanoclusters (AgNCs) as ECL emitters and Fe₃O₄–CeO₂ nanocomposites as a coreaction accelerator. The ECL luminous efficiency of AgNCs on the electrode could be significantly enhanced with the use of the Fe₃O₄–CeO₂ for accelerating the reduction of S₂O₈^2– to generate the strong oxidizing intermediate radical SO₄^•–. As a result, the assay for CCND1 detection achieved excellent sensitivity with a linear range from 50 fg/mL to 50 ng/mL and limit of detection down to 28 fg/mL. Impressively, the efficiency of Traditional Chinese Medicines (TCM), sophorae, toward MCF-7 cells was successfully investigated due to the overexpression of CCND1 in relation to the growth and metastasis of MCF-7 human breast cancer cells. In general, the proposed strategy provided an effective method for anticancer drug screening and expanded the application of metal NCs in ultrasensitive biodetection