Heparin-Conjugated Silver Nanoparticles via Amide Chemistry for Selective Targeting of Triple-Negative Breast Cancer...

Heparin, a polydisperse glycosaminoglycan, is well-known for its anticoagulant activity and clinical use in preventing venous thromboembolism. In addition to coagulation, heparin and its derivatives have shown therapeutic potential in cancer and infectious, inflammatory, and neurodegenerative diseases. This study aimed to develop and evaluate heparin-capped AgNPs (hep-AgNPs) as multifunctional nanotherapeutics with selective cytotoxicity, antibacterial, and antifungal activity.

Heparin was covalently conjugated to cysteamine-terminated silver nanoparticles via MES-buffer-mediated amide coupling, providing a mild, aqueous alternative to conventional DMF-based methods. The nanoparticles were characterised by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The colloidal stability was assessed over a broad range of pH values. The biological performance of hep-AgNPs was evaluated in vitro against a triple-negative breast cancer (TNBC) cell line (MDA-MB-231), a double-positive cell line (MCF-7), and normal breast cells (MCF-10A), and microbial strains, including Salmonella typhimurium, E. coli, Aspergillus fumigatus, and Candida albicans.

The synthesised hep-AgNPs exhibited high yield, effective heparin surface functionalization, and excellent colloidal stability at physiological pH, with stability systematically assessed across a broad pH range. Hep-AgNPs demonstrated time and concentration-dependent selective cytotoxicity, toward breast cancer cells, including MCF-7 and triple-negative MDA-MB-231, with a favourable selectivity index (>1) compared to MCF-10A cells, and the strongest selectivity observed in the TNBC model at 48 h. In addition, hep-AgNPs showed potent antibacterial activity (IC₅₀ = 24.3 µg/mL) and antifungal activity (IC₅₀ = 6.2 µg/mL for A. fumigatus and 24.43 µg/mL for C. albicans). In addition, they exhibit strong biocompatibility with keratinocytes and fibroblasts.

Heparin-capped silver nanoparticles combine the biological functionality of heparin with the antimicrobial and selective cytotoxic properties of the silver nanoparticles. Their selective cytotoxicity, antimicrobial efficacy, and favourable cellular interaction profiles highlight their potential as multifunctional nanoplatforms for applications such as chronic wound management in neutral to alkaline wound environments, and dose-controlled, targeted therapeutic strategies relevant to aggressive cancer models, including TNBC.