Magnetic Fe₃O₄ Nanoparticles Modified Hydroxyapatite Whisker: A Novel Framework with Superior Osteogenic Efficacy

The valid repair of bone defects requires considering precise elements mirroring native tissue and the efficiency of treatment reality. Magnetic biomaterial-mediated mechanotransduction emerges as a critical mechanism for enhancing osteogenic differentiation and bone regeneration. Here, enhancement of osteogenic capacity is achieved in a hydroxyapatite whisker (HAw) by integrating with magnetic Fe₃O₄ nanoparticles (HAw/Fe₃O₄). The HAw/Fe₃O₄ exhibited excellent magnetic responsiveness and controllable alignment along magnetic field (MF) vectors enabled precise delivery of programmed mechanical stimuli. In vitro and in vivo experiments showed that Fe₃O₄ nanoparticles modified HAw has satisfactory biocompatibility and osteoinductivity, while the synergistic efficacy of magnetic biomaterial with external MF stimulation significantly accelerated bone matrix mineralization. The magnetic HAw/Fe₃O₄ with a MF significantly increased the expression of osteogenic markers and improved bone repair. The mechanosensitive ion channel of Piezo1 enabled efficient transcellular mechanotransduction through the MAPK pathway in response to the magnetic HAw/Fe₃O₄ with MF stimulation. The current study demonstrates that the HAw/Fe₃O₄ magnetic framework - developed through Fe₃O₄ nanoparticle integration to enhance HAw osteoinductivity via coordinated MF application and mechanobiological modulation - served as an optimal therapeutic platform for delivering programmed mechanical cues to activate Piezo1-mediated mechanotransduction cascades, ultimately accelerating bone tissue regeneration.