Bi2S3-embedded mesoporous silica nanoparticles for efficient drug delivery and interstitial radiotherapy sensitization.

A novel design of Bi2S3 nanoparticles with a coating of mesoporous silica (BMSN) is obtained by a surfactant induced condensation method. It was found that BMSNs exhibited a high doxorubicin (DOX) loading efficiency of 45 wt% and pH-responsive controlled drug release owing to the electrostatic interaction between silanol surface and DOX molecules. The cell viability results demonstrated the encapsulation of DOX into BMSNs could lead to significantly enhanced therapeutic effect against multidrug-resistance cancer cells compared to that of free DOX drug. Furthermore, the comparable study of tumor growth by different treatments demonstrated that the introduction of BMSNs in the X-ray therapy could lead to higher therapeutic effect, with just 2.10-fold increase in tumor volume through 24 days, in comparison to 4.40-fold increase for X-ray beams treatment alone. Meanwhile, the in vitro interstitial radiotherapy experiments demonstrated that the cell inhibiting effect of P-32 interstitial radiotherapy combined with BMSNs (50 μg/mL) was 1.55-fold higher than that of P-32 alone. Significantly, it is notable that the simultaneous chemo- and interstitial radiotherapy based on BMSNs could tremendously increase the therapeutic effect compared to those treatment alone. More importantly, the in vivo P-32 radiotherapy in conjunction with BMSNs was proved to present a significantly eradication of the tumor volumes by an average of 21% reduction to its initial values, in comparison to 2.01-fold increase in case of P-32 treatment alone. Thus, it is expected that the BMSNs could be applied as a highly efficient multifunctional nanosystem to realize the enhanced chemo- and radiotherapy in the further clinical applications.