3D-printed microfibers encapsulating stem cells in scaffold with tri-culture and two-stage metformin release for bone/vasculature/nerve regeneration in rats
Minjia Zhu, Xinyi Li, Le Xiao, Kan Yu, Jingyi Li, Zixiang Dai, Qinrou Zhang, Jialiang Dai, Zihan Jia, Yuxing Bai, Ke Zhang
Abstract
Introduction: Regeneration of critical-sized bone defects remains a major clinical challenge. Solely promoting osteogenesis is inadequate, because vasculature and neural innervation are critical for establishing the bone regenerative microenvironment. Objective: For the first time, the present study developed 3D bio-printed hydrogel microfibers (aMF) encapsulating human periodontal ligament stem cells (hPDLSCs) in a tri-culture system in calcium phosphate cement (CPC) scaffold with a two-stage metformin release for regeneration of nerve, vasculature, and bone. Materials and methods: This tri-culture system consisted of hPDLSCs, human umbilical vein endothelial cells (hUVECs), and pericytes (PCs). Moreover, we employed 3D-bioprinted aMF in CPC scaffold with a controlled two-stage release system for metformin release to promote bone, vasculature, and nerve regeneration. Results: Our innovative construct increased the regenerated amounts of bone, vasculature and nerve significantly by 2.5-fold, 3-fold, and 3.5-fold, respectively, than control group, in cranial defects in rats. Conclusion: This novel hPDLSCs tri-culture system in aMF-CPC scaffold with two-stage metformin release is highly promising for the regeneration of all three tissues of bone, vasculature, and nerves in a wide range of craniofacial and orthopedic applications.