ROS-responsive chlorin e6 and silk fibroin loaded ultrathin magnetic hydroxyapatite nanorods for T1-magnetic resonance imaging guided photodynamic therapy in vitro

Magnetite hydroxyapatite nanoparticles show notable multifunctional therapeutic features in nanomedicine. However, designing MHAp nanoparticles with optimum dimensions, good stability and biocompatibility for specific biomedical applications is still in its infancy. Herein, a facile approach was employed to prepare ROS-responsive chlorin e6 and silk fibroin-loaded ultrathin magnetic hydroxyapatite nanorods for T1-magnetic resonance imaging and photodynamic therapy. Specifically, the Fe3O4-HAp nanorods were synthesized by the hydrothermal method, and then Pluronic® F-127 was used to improve the aqueous dispersion, biocompatibility, and loading capacity. Moreover, silk fibroin protein was encapsulated by a tri-block copolymer with good loading efficiency. Finally, the theranostic nano-assembly MHNRs-SF-Ce6 was completed by the addition of Ce6. The prepared MHNRs demonstrated excellent biocompatibility, cellular uptake, and ROS generation ability in in vitro after 660 nm laser irradiation, leading to the apoptosis of 4T1 mouse breast cancer cells. Notably, the designed MHNRs exhibited excellent r1 relaxivity value and T1 magnetic resonance imaging in vitro due to their minimal width (2 nm) of nanorods. Therefore, the obtained MHNRs-SF-Ce6 self-assembled nanoparticles provide an effective strategy for cancer diagnosis and photodynamic therapy.