Piezoelectric Porous Stereocomplex Poly(lactic acid) Empowers Bone Substitutes for Accelerated Vascularized Bone Regeneration

The clinical management of bone defects remains challenging due to the insufficient osteogenic and angiogenic capabilities of current bone substitutes. Developing a functional enhancer that endows bone substitutes with effective osteoinductivity and angiogenic potential may offer a promising strategy to improve bone repair outcomes. In this context, piezoelectric biomaterials have emerged as attractive candidates for stimulating bone regeneration by generating endogenous electrical signals under mechanical loading. Herein, an approach employing biodegradable poly(lactic acid) (PLA) with exceptional piezoelectricity through stereocomplex crystallization and porous structuring is introduced to provide self-powered electrical stimulation for enhancing bone substitutes performance. In vitro, the incorporation of porous stereocomplex PLA (SC-PLA) and hydroxyapatite (HAp, the primary inorganic component of bone) optimized the osteogenic microenvironment, significantly enhancing osteogenesis and angiogenesis under mechanical vibration. To further validate the functional enhancement of porous SC-PLA, the clinically established BioOss (deproteinized bovine bone primarily composed of HAp) was employed for animal studies. In vivo, porous SC-PLA markedly improved bone repair efficacy of BioOss, achieving near-complete regeneration within 12 weeks with newly formed bone resembling native tissue and elevated expression of osteogenic and angiogenic markers. These findings demonstrate the potential of piezoelectric porous SC-PLA as a functional enhancer for bone substitutes, providing insights into bone tissue engineering.