Biodegradable piezoelectric polymer for cartilage remodeling

In vivo applications of piezoelectric materials are hindered due to their poor biocompatibility and non-biodegradability. Poly-L-lactide (PLLA) as a promising piezoelectric biomaterial has been verified to promote tissue repair. Nevertheless, the low piezoelectric coefficient of PLLA tremendously reduces the potential of piezoelectric stimulation therapy in situ. Herein, we create a biodegradable piezoelectric composite made of two homologous polymers, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PLLA. The composite (termed 0.7PHBV) with a reduced modulus and an increased piezoelectricity possesses a piezoelectric coefficient of 2.0–2.5 times greater than PLLA. Both PHBV and PLLA have homolog monomers that exhibit similar chiral carbon atoms, facilitating partial miscibility during composite formation. 0.7PHBV with excellent biodegradability and favorable piezoelectricity can effectively enhance cartilage remodeling through calcium and transforming growth factor β signaling pathways. This study represents an alternative approach to self-powered bio-piezoelectric materials for remodeling tissues in stressed sites through piezoresponse.