Magnetical scafford with ROS-scavenging for bone regeneration under static magnetic field

Excessive reactive oxygen species (ROS) and bacterial infection significantly disrupt the microenvironment of tissue regeneration. Magnetic nanoparticles in combination with magnetic fields are emerging strategies to regulate tissue regeneration. In this work, ZnFe₂O₄ (ZFO) nanoparticles were prepared and subsequently decorated with polydopamine (PDA) and RGD peptide. The modified ZFO nanoparticles were loaded into polylactic-glycolic acid/polycaprolactone (PLGA/PCL) scaffolds as PP-ZFO/PDA-RGD magnetic scaffolds. Physicochemical, anti-ROS, antibacterial and osteogenic properties were evaluated in vitro. Under 30 mT static magnetic field, the PP-ZFO/PDA-RGD scaffold significantly enhanced the expression of ALP, RUNX2, BMP2 and mineralized nodules. It indicated that the magnetic system could promote the attachment, proliferation, differentiation and mineralization of MC3T3-E1 cells. The scaffold showed excellent ROS scavenging ability via the additive effect of ZFO, PDA and RGD. The remarkable antibacterial properties of Zn²⁺ and Fe³⁺ endowed the scaffolds with excellent antibacterial activity against E. coli and S. aureus. These results demonstrate that the PP-ZFO/PDA-RGD based magnetic system is a promising approach for bone regeneration under complex microenvironment.