Organic Functionalization of Mesoporous Silica Spheres as a Nanovehicle for DOX pH-Triggered Delivery

Mesoporous silica (MS) spheres of different sizes with pH-responsive characteristics were synthesized based on Stober's theory. Organic functionalization with aminopropyl and carboxyl groups resulted in different materials, namely, MS@NH2@COOH. MS@NH2@COOH were observed to have a large number of carboxyl groups and multiamine chains, and were grafted into pore channels and pore outlets through systematic characterization analyses. All modified samples demonstrated the controlling of the delivery rate of DOX from the siliceous matrix. We also compared the drug release behavior of the DOX-loaded materials at high pH (7.4) and low pH (5.5) and studied the cytotoxicity on A549 cells. The experimental results indicated that the drug delivery system can better control drug release and have potential applications in the drug delivery field.