Folic acid-modified chitosan nanoparticles for targeted delivery of a binuclear Co(II) complex in cancer therapy

A salient challenge in cancer chemotherapy is the successful delivery of drugs to cancer cells. Therapeutic agents can be delivered to cancer cells in a targeted and efficient manner using nanoparticles (NPs). Herein, we present the molecular characterization of a novel binuclear Co(II) complex with octahedral geometry based on Schiff base from dehydroacetic acid and piperazine derivatives. DNA and BSA binding interactions were investigated using UV-Vis spectroscopy and gel electrophoresis. In vitro cytotoxicity of Co(II) complex was assessed against microbes and human cells (Cancer: MDA-MB-231, MCF7, A375, HepG2; Non-cancerous: HSF, WI-38) using well diffusion and MTT assays. Chitosan decorated with folic acid (CS-FA) was fabricated to encapsulate Co(II) complex, which may serve as a nano-targeted drug delivery system, to dampen its adverse effects on non-cancerous cells. TEM and DLS analysis confirmed nano-sized and stable monodisperse nanosuspension of both (CS-FA) and (CS-FA-Co(II) complex) systems. CS-FA-Co(II) complex NPs exhibited an 8.3-fold increase in cytotoxicity against folate-receptor-positive MDA-MB-231 cells, while remaining safe for folate-receptor-negative HSF cells. They also induced cell cycle arrest, inhibited migration, and triggered apoptosis by modulating Bax, Bcl-2, caspase-3, and CDH1. These findings highlight CS-FA NPs as a promising targeted delivery system for Co(II) complex-based cancer therapeutic agents, offering improved efficacy.