pH-triggered Charge-Reversal Mesoporous Silica Nanoparticles stabilized by Chitosan oligosaccharide/Carboxymethyl Chitosan hybrids for Effective Intracellular Delivery of Doxorubicin

Surface modification of mesoporous silica nanoparticles (MSNs) is a promising way to enhance therapeutic efficacy and minimize side effects of anticancer drugs. In this work, MSNs with reduced particle size and optimum pore diameter were obtained and catalyzed by ammonia/triethanolamine. In view of the negatively charged carboxymethyl chitosan (CMC) and positively charged chitosan oligosaccharide (CS), the pH-triggered charge-reversal CS/CMC bilayer was designed as a stimuli-responsive switch for MSNs via the protonation and deprotonation effect. The results showed that MSNs-CS/CMC were core–shell and mesoporous in structure. Surface charge conversion and pH dependence were clearly observed in the doxorubicin hydrochloride (DOX) delivery. The intracellular uptake indicated that DOX@MSNs-CS/CMC could be distributed in the cytoplasm of MCF-7 cells and exhibited lower toxicity, which would improve the stability and prolong the retention time compared to free DOX and unmodified DOX@MSNs at pH 7.4. Moreover, t...