Direct Formation of Silk Nanoparticles for Drug Delivery

Silk is useful as a drug carrier because of its biocompatibility, tunable degradation, and capacity in maintaining the function of drugs. However, further refinements are still required for silk-based nanoparticles to optimize applications as anticancer drug delivery systems. Here, a novel strategy was developed to prepare silk nanoparticles with improved performance. Unlike previous preparation methods that first obtain silk solutions and then induce nanoparticle formation through different treatments, here silk nanoparticles were directly prepared after a modified dissolution process. The nanoparticles had amorphous structure and homogeneous morphology, as well as improved dispersion in water and PBS solutions and improved pH-dependent drug release behavior when compared with the traditionally prepared silk nanoparticles. These improvements resulted in better uptake of the nanoparticles into cancer cells and higher cytotoxicity against cancer cells. These properties, when combined with the simpler and milder preparation process, indicate potential utility for anticancer drug delivery.