Fig. 1: Design and characterization of the self-reinforced piezoelectric chip for scaffold-free repair of critical-sized bone defects.
From: Self-reinforced piezoelectric chip for scaffold-free repair of critical-sized bone defects
a The smart chip is a multilayer structure, including a Si substrate, Mo electrodes, and an AlN piezoelectric layer (II). An internal cavity was etched into the Si substrate using a wet etching method to enhance sensitivity to physiological vibrations (I). The chip generates alternating electrical signals under vibration, converting mechanical energy into a localized bioelectric microenvironment. After being integrated with a clinically used plate and implanted at the critical-sized bone defect site (III), the chip synergistically activates the PI3K/Akt signaling pathway (V), thereby promoting the proliferation and osteogenic differentiation of stem cells (IV). Meanwhile, the chip enhances angiogenesis by upregulating VEGF-A and CD31 expression. Hence, the chip provides a promising strategy for critical-sized bone defect repair through robust electrical stimulation and vascularized bone regeneration, achieving an efficient scaffold-free bone repair. b Photos of the chip. c Cross-sectional SEM images of the chip with a 10 × 3 mm2 cavity. d Schematic diagram of the current testing system for the chips. A testing disk with a central cavity (10 × 5 mm2) is used to simulate a bone defect. The chips are adhered to a Ti6Al4V plate using Polydimethylsiloxane (PDMS), and then the plate is fixed across the defect with screws. A vertical cyclic force (0.5 N at 1−4 Hz) is applied perpendicular to the disk to mimic physiological vibration. e Electrical signal of the chips integrated with Ti6Al4V plates under vibration. f Statistical analysis of current density derived from panel (e). Data are presented as mean ± SD (n = 11). Two-sided ANOVA with a Tukey’s post hoc test for multiple comparisons. Source data are provided as a Source Data file.
