Mesostructured chitosan-silica hybrid as a biodegradable carrier for a pH-responsive drug delivery system

A biodegradable mesoporous chitosan-silica hybrid has been synthesized by self-assembly of non-toxic F127 Pluronic non-ionic surfactant, biodegradable chitosan and silica source through a real liquid-crystal templating route. On the basis of these biodegradable hybrids, we developed a facile one-pot pH-responsive drug delivery system relying on the coordinate bonding of a "host-metal-guest" architecture. Here, the "host", "metal" and "guest" represent amino groups of chitosan units, metal ions and drug molecules, respectively. Here, daunorubicin (DNR) was chosen as a typical anti-cancer drug molecule, the release of which can be achieved through the cleavage of the coordination bonds that are sensitive to variations in external pH at weak acidic conditions. The successful release of DNR has been observed at pH 5-6, while negligible release has been observed under physiological conditions. The existence of chitosan in the mesoporous silica enhanced both the biodegradability and the strength of the "host-metal-guest" coordination bond.