Abstract:
Articular osteochondral tissue exhibits a continuously graded piezoelectric property along its thickness direction. A key challenge for integrated osteochondral repair is how to spatially regulate piezoelectric signals within a scaffold and thereby guide region-specific stem cell differentiation. To address this issue, a biomimetic piezoelectric active gradient hydrogel was constructed using inorganic functional particles as the magnetic-responsive core. Specifically, bioactive glass (BG) was coated onto Fe
3O
4 surfaces to form core-shell structured magnetized BG (FB), which combines bio-compatibility, magnetic responsiveness, and osteogenic activity. This inorganic magnetic component was compounded with piezoelectric poly(L-lactic acid), and the mixture was electrospun and cryosectioned into magnetized composite short fibers. These fibers were dispersed in gelatin methacryloyl hydrogel, where a magnetic field was applied to drive their continuous gradient distribution along the thickness direction, followed by pho-to-crosslinking to obtain an integrated scaffold. Experimental results show that the gradient distribution of composite short fibers was successfully guided by FB under a magnetic field. This gradient scaffold produces a graded piezoelectric signal ranging from about 150 mV in the upper layer to nearly 300 mV in the bottom layer, and directs cells to differentiate selectively along the thickness direction. These findings confirm that the magnetic field-induced gradient strategy is feasible and provides a biomimetic route for integrated osteochondral repair.