Facile fabrication of nanocarriers with yolk-shell mesoporous silica nanoparticles for effective drug delivery

Abstract

Drug delivery systems (DDSs) can greatly reduce the negative impact of chemotherapy in the treatment of tumors by alleviating issues such as low solubility, short half-life, and strong side effects of chemotherapeutic drugs. Therefore, engineering DDSs is of great significance. Herein, we report an innovative magnetic delivery system with a yolk-shell structure and targeting function, comprising a magnetic core and a mesoporous silica shell. The yolk-shell-structure was fabricated by the swelling-shrinkage process of resorcinol-formaldehyde resin upon soaking in or removal of hexane, while a silica shell was formed. The hydrophobic resin layer, hollow cavity, and channels of the shell improved the drug loading and afforded sustained drug release. The desired drug carriers (denoted as Fe3O4@YSSiO2-FA) were labeled with folate to promote biocompatibility and targeting functions. The prepared Fe3O4@YSSiO2-FA with particle sizes ranging from 100 to 200 nm had a loading capacity of 220 μg mg−1 for camptothecin (CPT) and afforded sustained release over 72 h in vitro. Fe3O4@YSSiO2-FA presented a lower protein adsorption capacity, a hemolysis rate of less than 1.2%, and weak cytotoxicity for A549 cells, with a cell viability of more than 74%, indicating that the proposed nanocarriers possess excellent biocompatibility. CPT-loaded Fe3O4@YSSiO2-FA showed higher cytotoxicity for KB cells (FA-receptor-positive) due to the higher cellular uptake compared to A549 cells (FA-receptor-negative), likely suggesting a preeminent tumor-specific targeting ability. The superior loading capacity, targeting ability, and biocompatibility demonstrate that Fe3O4@YSSiO2-FA possesses great potential as a carrier for DDSs. As expected, the developed strategy provides a facile alternative for fabricating efficient DDSs for antitumor applications.