Folic acid functionalized exopolysaccharide integrated into a coordination polymer for targeted and controlled drug release.

An exopolysaccharide (EPS) isolated from Enterococcus faecium was functionalized with folic acid (FA) via carbodiimide-mediated coupling using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-Hydroxysuccinimide. This reaction facilitated the formation of an amide linkage between the primary amine group of FA and the carboxyl group of the EPS. The synthesized FA-functionalized EPS (FA-EPS) was further incorporated into a photothermally active coordination polymer matrix along with an anticancer drug to achieve a controlled drug release system targeting SH-SY5Y neuroblastoma cells. Physical interactions between polar groups of FA-EPS and drugs, including hydrogen bonding, electrostatic forces, and π-π stacking, enable efficient drug encapsulation within the FA-EPS matrix, resulting in controlled and sustained drug release that enhances therapeutic efficacy and minimizes toxicity. Moreover, the integration with the coordination polymer imparted photothermal properties, resulting in a synergistic enhancement of apoptosis through combined chemo-photothermal therapy. Flow cytometric analysis was subsequently performed to evaluate apoptosis in SH-SY5Y cells treated with the prepared composites, confirming the targeted and multifunctional therapeutic efficacy of these composites.