Effects of physico-chemical properties of ions-doped hydroxyapatite on adsorption and release performance of doxorubicin as a model anticancer drug

Hydroxyapatite (HAp) is considered to be one of the most promising materials for anticancer drug carrier due to its excellent biocompatibility and adsorption capacity. Herein, we thoroughly evaluated the key factors affecting the performance of HAp used as a drug carrier of doxorubicin (DOX), including ion-doping, specific surface area, zeta potential, binding energy, etc. The results showed that Zn, Ba, F, Zn/F, and Ba/F ions were successfully doped into the lattice structure of HAp by a simple hydrothermal method. Compared with pure HAp, the doping of these ions can not only improve its specific surface area and zeta potential, but also enhance the binding energy between DOX and HAp, and thus improving the DOX loading capacity and sustained release time. Moreover, among all the samples, the Ba/F codoped HAp exhibits the highest DOX loading efficiency (96.3%), followed by Ba doped HAp (93.4%), and both of them shows pH-dependent sustained release behavior. Our study indicates that the DOX loading capacity of HAp can be further improved and the sustained release time can be prolonged by selecting appropriate ions for HAp doping, which is of great significance to promote the clinical application of HAp as a drug carrier of DOX.