Piezoelectrical biomaterials designed for enhanced bone and cartilage regeneration

The limited sources for biodegradable piezeoelectric biomaterials trigger a highlighted interests in developing new material strategies for bone and cartilage regeneration. Herein, we prepared several piezoelectric biomaterials, including Ca/Mn co-doped barium titanate (CMBT), piezoelectric whitlockite (PWH), poly(L-lactide) (PLLA), silk fibrin (SF) and phenylalanine dipeptide (FF) modified scaffolds, to evaluate their potentials for boosting bone/cartilage regeneration via in vitro and in vivo characterizations. Briefly, the outcomes are summarized as: 1) The produced CMBT nanofibers show enhanced degradability with sustained release of bioactive Ca2+ and Mn2+. The efficiency of bone regeneration is significantly improved as the CMBT nanofibers composited with polarized PLLA scaffold or conductive gelatin hydrogel. 2) The PWH is produced via sintering whitlockite, which synergistically provide bioactive ions (Mg2+, Ca2+) and piezoelectricity to promote angiogenesis and osteogenesis. Porous scaffolds and injectable microspheres containing PWH are fabricated to repair calvarial or segmented radius defect. 3) For osteochondral regeneration, a two-layered FF-modified scaffold is fabricated with conductive component introduced into the bone layer, which facilitates charge transfer from the upper part to the lower part with the knee movement generating pressure on the implanted scaffold. The cartilage and subcartilage bone are simultaneously repaired to high extents with the heterogeneous electroactive scaffold. With these approaches, it provides some foundation for more novel designs to aid regenerative researches.