Synergistic Effects of CoHCF@MWCNTs@FA Nanocomposites Enhancing Photodynamic Therapy for Triple-Negative Breast Cancer

This study presents the synthesis of a ternary nanocomposite containing cobalt hexacyanoferrate, multiwalled carbon nanotubes, and folic acid (CoHCF@MWCNTf@FA) for application in photodynamic therapy (PDT), a minimally invasive approach for the treatment of triple-negative breast cancer. The choice of components was based on their photosensitizing properties and biocompatibility. The nanocomposites showed remarkable stability in biological medium, maintaining their structure and preventing cobalt leakage during incubation. Their efficient internalization by tumor cells (60–70%), particularly for the ternary nanocomposite, highlights the role of receptor-mediated uptake in enhancing the photodynamic response. Cell viability assays in the triple-negative breast cancer cell line (MDA-MB-231) showed that the carbon nanotube (MWCNTf) is noncytotoxic (cell viability ≥ 70%) and the isolated material CoHCF exhibited low cytotoxicity (cell viability ≥ 60%) at the tested concentrations. In contrast, under red light-emitting diode irradiation, the CoHCF@MWCNTf@FA nanocomposite induced 79% cell death at concentrations of 0.8 and 1.0 mg mL–1, demonstrating a significant photodynamic effect. Apoptosis data correlated with the phototoxicity results, confirming that the ternary nanocomposite showed the best performance in inducing cell death via late apoptosis of tumor cells. The ternary nanocomposite also exhibited selective phototoxicity, significantly reducing the viability of MCF-7 tumor cells (below 44%) upon irradiation, while maintaining high viability (>84%) in nontumorigenic MCF-10A cells. These results highlight the synergistic properties and potential of this nanocomposite as a promising candidate for the treatment of breast cancer through PDT.