A multifunctional mesoporous silica nanocomposite for targeted delivery, controlled release of doxorubicin and bioimaging.

In this study, a targeting drug delivery system based on mesoporous silica nanoparticle (MSN) was successfully developed for anti-cancer drug delivery and bioimaging. Carboxyl functionalized MSN (MSN/COOH) was firstly prepared and then modified with folate as the cancer targeting moiety and a near infrared fluorescent dye as labeling segment. Folate was conjugated to MSN/COOH via functional polyethyleneglycol (PEG), constructing the vector MSN/COOH-PEG-FA. The functionalization with carboxyl caused the pore surface of the nanocarrier more negative than native MSN, which could provide attractive forces between the nanoparticles and positively charged doxorubicin hydrochloride (DOX). Meanwhile, the folate modification significantly enhanced the cellular uptake of the delivery system compared to unmodified counterparts. Furthermore, the introduction of PEG increased the water dispersibility. Besides, the modification with the near infrared fluorescent dye Cy5 made the system effective for live cell and in vivo imaging. Therefore, the Cy5-MSN/COOH-PEG-FA system could be a promising nanocarrier for simultaneous diagnosis and treatment of diseases.