Construction of a nano-fluorescent polymer drug delivery system for breast cancer treatment

Abstract

A novel heterometallic coordination polymer (CP1), {[(CH3)2NH2]2[CdNa2(2,5-pydc)3]}n (1,2,5-H2pydc = 2,5-pyridine dicarboxylic acid), was synthesized using solvothermal reactions involving Na(I), Cd(II), and 2,5-H2pydc salts. X-ray structural analysis revealed that CP1 forms a robust three-dimensional anionic framework, stabilized by lattice dimethylamine cations, and exhibits solid-state luminescence at room temperature. Notably, CP1 demonstrated remarkable thermal stability, with decomposition only occurring at temperatures above 480 °C. The solid-state luminescence of CP1 showed a significant blue shift, emitting at 452 nm (λex=380 nm), compared to the free ligand 2,5-H2pydc, which emitted at 515 nm under the same excitation conditions. To address the inherent solubility and biotoxicity limitations of CP1, we developed a novel, biodegradable, and non-toxic drug delivery system by integrating CP1 with sodium alginate (SA), forming SA-CP1. This innovative nanocarrier displayed excellent fluorescent responsiveness and facilitated sustained drug release in aqueous media, significantly improving bioavailability and minimizing cytotoxicity. We further demonstrated the therapeutic potential of this system by loading it with letrozole (Femara), an anti-tumor drug, through ionic interactions and hydrogen bonding, resulting in the formation of SA-CP1@letrozole (Femara). The efficacy of SA-CP1@letrozole (Femara) was evaluated on cisplatin-resistant MDA-MB-231 triple-negative breast cancer (TNBC) cells. The results indicate that SA-CP1@letrozole (Femara) effectively reduced cell viability and demonstrated potential in reversing drug resistance in MDA-MB-231/DDP cells. These findings underscore the potential of SA-CP1 as a versatile platform for targeted drug delivery and cancer therapy.