Print-and-Roll Hierarchically Structured Piezoelectric Scaffolds for Exercise-Driven Cartilage Regeneration

Electrical stimulation (ES) therapy accelerates cartilage healing but faces challenges due to bulky equipment, necessitating the development of a lightweight, implantable, and biocompatible electrical stimulator for improved patient compliance and benefits. Piezoelectric materials have garnered considerable attention for their potential as self-driven bioelectric therapies to treat osteoarthritis (OA) by providing in situ ES. Accordingly, an ES therapy for exercise-driven cartilage regeneration based on hierarchically structured piezoelectric scaffolds is proposed. Piezoelectric scaffolds composed of polyvinylidene fluoride/zinc oxide/polycaprolactone (PZP) are fabricated using combined 3D printing and rolling techniques, showing potential to promote cartilage regeneration as a treatment for OA. The developed PZP scaffolds possess favorable electrical signal-generation capability, good biocompatibility, and strong degradation resistance. Moreover, the PZP scaffolds can promote chondrocyte proliferation, and inhibit inflammation and degradation of the matrix in vitro. Besides, rats with osteochondral defects receiving PZP scaffolds exhibited significant morphological and functional cartilage restoration at 1–2 months after implantation. This study underscores the potential of an efficient and user-friendly piezoelectric scaffold system to generate electrical signals that promote cartilage regeneration.