Chitosan-capped silver nanoparticles with potent and selective intrinsic activity against the breast cancer cells

Herein, we report on the development of chitosan-capped silver nanoparticles (AgNPs-CHI) with an intrinsic activity against breast cancer cells. Following chemical synthesis via a simple, one-pot reaction, the chitosan coating of AgNPs was verified using Fourier-transform infrared and ultraviolet-visible spectroscopies. The physicochemical properties and morphology were characterized using dynamic light scattering, scanning electron microscopy, and transmission electron microscopy. The shelf stability of the optimized platform was tracked for 3 months upon storage at either room temperature or 4 degrees C. Then, the anticancer activities of AgNPs-CHI on human breast cancer cells, MCF-7, versus normal human cells, human skin fibroblasts (HSF), were evaluated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxicity assay and tumor-associated biomarkers determination by enzyme-linked immunosorbent assay, in comparison with plain silver nitrate (AgNO3) solution. AgNPs were successfully coated with chitosan and demonstrated acceptable physicochemical properties, with a spherical morphology and high stability upon long-term storage. Although AgNPs-CHI and AgNO3 demonstrated comparable cytotoxicity to MCF-7 cells, AgNPs-CHI resulted in 10-fold lower toxicity to HSF cells, suggesting a higher selectivity. In addition, AgNPs-CHI lowered IL-6 and tumor necrosis factor-alpha levels in MCF-7 cells by 90 and 30%, respectively, compared to 60 and 10% in the case of plain AgNO3. The interesting therapeutic modality presented in this study is promising for potential clinical applications.