The scaffold for tissue engineering not only requires good biocompatibility, mechanical properties, and appropriate structure, but also should actively participate in biophysical and biochemical processes to accelerate tissue repair. A piezoelectric scaffold can generate electrical activity when deformed, which constructs an electrochemical microenvironment for inducing cell signaling pathways and facilitating tissue regeneration, attracting extensive attention in tissue engineering. Herein, piezoelectric materials used in tissue engineering, including piezoelectric ceramics, synthetic piezoelectric polymers, and natural biological piezoelectric materials are systematically summarized, and their advantages and limitations are analyzed. As for the piezoelectric scaffold, the piezoelectric properties mainly stem from the asymmetric crystal structure of materials and the directional arrangement of internal dipoles, which is highly dependent on the fabrication and post-treatment strategies. Therefore, the fabrication techniques of piezoelectric scaffold are detailly introduced, covering both traditional fabrication techniques and additive manufacturing techniques. Besides, rational structural design of the piezoelectric scaffold can alter strain transmission pathways and charge distribution, or add new operational modes to regulate piezoelectric properties. Thereby, the piezoelectric metamaterials, micro/nanostructures, porous structures, heterogeneous structures, and biomimetic structures are comprehensively summarized. Additionally, the functions of piezoelectric scaffold for tissue engineering application in terms of bone regeneration, neural regeneration, antibacterial activity, and intelligent sensing are reviewed. Finally, the challenges and future research directions of the piezoelectric scaffold are discussed.

Bacterial infection is a major issue after artificial bone transplantation due to the absence of antibacterial function of bone scaffold, which seriously causes the transplant failure and even amputation in severe cases. In this study, oxygen vacancy (OV) defects Fe-doped TiO₂ (OV-FeTiO₂) nanoparticles were synthesized by nano TiO₂ and Fe₃O₄ via high-energy ball milling, which was then incorporated into polycaprolactone/polyglycolic acid (PCLGA) biodegradable polymer matrix to construct composite bone scaffold with good antibacterial activities by selective laser sintering. The results indicated that OV defects were introduced into the core/shell-structured OV-FeTiO₂ nanoparticles through multiple welding and breaking during the high-energy ball milling, which facilitated the adsorption of hydrogen peroxide (H₂O₂) in the bacterial infection microenvironment at the bone transplant site. The accumulated H₂O₂ could amplify the Fenton reaction efficiency to induce more hydroxyl radicals (·OH), thereby resulting in more bacterial deaths through ·OH-mediated oxidative damage. This antibacterial strategy had more effective broad-spectrum antibacterial properties against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). In addition, the PCLGA/OV-FeTiO₂ scaffold possessed mechanical properties that match those of human cancellous bone and good biocompatibility including cell attachment, proliferation and osteogenic differentiation.