A facile strategy to fabricate a pH-responsive mesoporous silica nanoparticle end-capped with amphiphilic peptides by self-assembly.

A facile strategy with no modification processes was demonstrated to fabricate a pH-responsive end-capped mesoporous silica nanoparticle (MSN)-based drug delivery system (DDS). The simple but smart nanovalve systems were constructed by the self-assembly behavior of unbonded peptide-based amphiphile (P45) in the presence of Doxorubicin hydrochloride (Dox). A series of characterizations confirmed that the DDSs had been successfully fabricated. Dox molecules were entrapped by nanovalves in the pores of MSNs, and an in vitro release experiment demonstrated that the P45/Dox@MSNs exhibited "zero premature release" in the physical environment. However, an accelerated release was triggered by an acidic atmosphere in cellular cytosol. Moreover, detailed investigations confirmed that the enhanced cellular uptake of P45/Dox@MSNs due to the RGD motif of the nanovalves, exhibiting an obvious toxicity to cancer cells. Therefore, the DDSs constructed here can serve as a promising platform to realize targeted drug delivery and controlled drug release by using diversified bioactive native amphiphilic peptide.