Gadolinium-Doped Hydroxyapatite Nanorods as T1 Contrast Agents and Drug Carriers for Breast Cancer Therapy

Hydroxyapatite nanoparticles have drawn much attention in the development of multifunctional nanosystems because of their excellent biocompatibility. In the report, gadolinium-doped hydroxyapatite nanorods (NHA:Gd) were controlled synthesized through adjusting the amount of gadolinium. The NHA:Gd showed a high loading capacity for doxorubicin (118 μg per milligram) and a pH-responsive drug release ability. The r1 value of obtained doxorubicin (DOX)-loaded NHA:Gd (NHA:Gd-DOX) solution reached 0.0472 (μg/mL)−1 s–1 and was higher than that of commercial T1 contrast Gd-DTPA (0.0314 (μg/mL)−1 s–1). In vivo experiments demonstrated that NHA:Gd-DOX exhibited excellent MR imaging property. The results of therapeutic efficacy demonstrate that the tumor volume treated by NHA:Gd-DOX was significantly reduced compared to that treated by free DOX. In vivo toxicity experiments demonstrated no obvious damage to the major organs in NHA:Gd-DOX treated mice. Considering the excellent biocompatibility, T1WI contrast ability, and enhanced therapeutic efficacy, these NHA:Gd-DOX have great potential for applications as MR T1 contrast agents and drug carriers for cancer therapy.