Bio-reductive hetero-bimetallic Co(iii)–Pt(ii) complex for tumor-selective platinum release and cytotoxicity

electrospray ionization mass spectrometry (ESI-MS), confirmed the reductive release of the Pt(II) fragment and its subsequent coordination with nucleophilic targets. Induction of apoptosis was verified using Annexin V assays, indicating the activation of programmed cell death pathways. The complex exhibited potent cytotoxicity under both normoxic and hypoxic conditions in A549 cells and showed significant activity against a panel of cancer cell lines, including HT-29 (colorectal), MCF-7 (breast), and MDA-MB-231, a highly aggressive triple-negative breast cancer line. These findings highlight the potential of this redox-responsive bimetallic complex as a next-generation anticancer agent capable of overcoming platinum resistance, enhancing tumor selectivity, and reducing systemic toxicity relative to conventional platinum-based therapies.