Novel stable and biocompatible poly L-lactide/β-glycine films for in vivo bone repairing by using nanogenerator with high piezoelectricity

Piezoelectric biomaterials can convert mechanical energy into electricity, which make them attractive for implant applications, such as sensing, energy harvesting, and medical devices. The β-glycine has excellent piezoelectric performance, but their practical use is hindered by instable crystal phase and water solubility. Here, we present a simple method for preparing poly L-lactide (PLLA) composite fibers encapsulating β-glycine nano crystals via coaxial electrospinning. The formation of β-glycine crystals is the synergistic outcome of the ionization of glycine solution under the electric field and the confinement of external PLLA solution, which enhances the piezoelectric performance of the film. The V oc , I sc , and power density of composite film reach 14 V, 0.94 μA, and 0.92 mW/cm 2 , respectively. In addition, PLLA shell stabilizes β-glycine, leading to a stable piezoelectric performance for device applications. The composite film can be ultrasonically driven to generate electric signals, and therefore functions well in promoting cell proliferation and bone tissue repairing in vivo . Moreover, the film can be naturally degraded after long-term implantation. This study provides a strategy to deal with the instability of β-glycine-based biodegradable piezoelectric films, and promotes the implant applications.