Combining vitamin B12 and cisplatin-loaded porous silica nanoparticles via coordination: a facile approach to prepare a targeted drug delivery system

Abstract

In this work, a novel drug delivery system for targeted therapy is developed based on noncovalent interactions. The strategy is to combine an active targeting unit and a passive targeting moiety via simple dative bonds. The system is composed of carboxyl group-modified porous silica nanoparticles (PSNs-C) as a drug carrier, cisplatin (CDDP) as an anticancer drug, and vitamin B₁₂ (B12) as an active targeting unit for tumor cells. PSNs-C were prepared by co-condensation of TEOS and carboxyethylsilane (CES) using CTAB as the porous template. B12 was then successfully decorated onto the drug-loaded particles via coordination to the cobalt center. The obtained particles were characterized by XRD, FT-IR, UV-vis, SEM and DLS. The particles were spherical and monodisperse with an average diameter of 316 ± 6 nm. In addition, B12 could control the drug release by serving as a gatekeeper to hinder drug leaching during circulation. Under a reducing environment at pH 5.5, the cobalt center in B12 was reduced and cleaved from the particles, which resulted in a significant enhancement of CDDP release.