Colloidal Stability of Silk Fibroin Nanoparticles Coated with Cationic Polymer for Effective Drug Delivery

Generally, silk fibroin nanoparticles (SFNPs) are great candidates to deliver drugs or other bioactive substances in vivo. However, their further applications are largely limited by the low colloidal stability of SFNPs, as they tend to aggregate in biological media. To address this issue, SFNP composite materials with a core-shell structure (CS-SFNPs) were fabricated by coating SFNPs with four different selected cationic polymers, glycol chitosan, N,N,N-trimethyl chitosan, polyethylenimine, and PEGylated polyethylenimine, through electrostatic interaction. According to the DLS and NTA results, compared with the bare SFNPs, the CS-SFNPs showed much higher colloidal stability in biological media. When treated with human cervical carcinoma (HeLa) cells, the CS-SFNPs were efficiently internalized and accumulated in lysosome; and when loaded with an anticancer drug, DOX, the CS-SFNPs also showed higher cytotoxicity against HeLa cells. Our results suggest that the fabricated CS-SFNPs with desirable colloidal stability in biological media have the potential to be employed as drug carriers for the anticancer drug delivery system.