The structural and surface properties of Al-doped hydroxyapatite (Ca₅(PO₄)₃OH) nanorods and their applications for pH-induced drug delivery

In this paper, we reported Al-doped hydroxyapatite (Al-HAp) nanorods with surface functionalization of hyaluronic acid (HA) for pH-responsive delivery of doxorubicin (DOX) for cancer treatment. The specific surface area and the crystal structure of both HAp and Al-HAp are studied. It is learned that the HAp and Al-HAp have similar crystal structures, but Al-HAp shows 10% larger specific surface area than HAp, which results in 30% higher DOX loading capacity than HAp nanorods, due to the increased surface area and enlarged pore size by Al doping. Moreover, the DOX loaded Al-HAp/HA was highly pH-responsive and exhibited outstanding biocompatibility and significantly enhanced anti-cancer killing effects.