Autofluorescent and pH-responsive mesoporous silica for cancer-targeted and controlled drug release

A new autofluorescent and pH-sensitive multifunctional drug release system is developed in this contribution by layer-by-layer assembly of chitosan (CHI)/dialdehyde starch (DAS) polyelectrolyte multilayers (PEM) onto mesoporous silica nanoparticles (MSN) surface. The formed mesoporous silica composites can be used as drug delivery carriers, which have very slow drug release rate at pH 7.4, but have very fast drug release rate at pH 5.0 owing to the breakage of C=N bonds of the CHI/DAS multilayers under acidic condition. As a proof of concept, folic acid (FA) has been conjugated to the outer surface of the mesoporous silica composites by the amide reaction in order to deliver target anticancer drug, and it is found that cellular uptake of the folate conjugated doxorubicin-loaded nanoparticles in folate receptor-overexpressing HeLa cells is much higher than that of non-folate receptor-overexpressing A549 cells, indicating that successful targeting drug release has realized. (C) 2013 Elsevier Inc. All rights reserved.