A Composite Deferoxamine/Black Phosphorus Nanosheet/Gelatin Hydrogel Scaffold for Ischemic Tibial Bone Repair

Dingli Xu,1,2,* Kaifeng Gan,3,* Yang Wang,1 Zeting Wu,1 Yulong Wang,1 Song Zhang,1 Yujie Peng,2 Xuguang Fang,4 Hua Wei,5 Yansheng Zhang,5 Weihu Ma,2 Jing Chen5 1The Affiliated Hospital of Ningbo University Medical School, Ningbo, 315000, People’s Republic of China; 2Ningbo No.6 Hospital, Ningbo, 315000, People’s Republic of China; 3The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 31500, People’s Republic of China; 4The First Affiliated Hospital of Xi ‘an Medical University, Xi’an, 710082, People’s Republic of China; 5Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Zhejiang Engineering Research Center for Biomedical Materials, Cixi Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315300, People’s Republic of China*These authors contributed equally to this workCorrespondence: Weihu Ma; Jing Chen, Email 944973034@qq.com; jing.chen@nimte.ac.cnIntroduction: Bone delay union is mostly caused by lack of blood supply. Although autografts, allografts and artificial bone have been widely used to treat bone delay union, the bone regeneration fails in the ischemic site accompanied by the bone donor site complications and disease transmission. Recently, there is a growing recognition of the importance of hydrogel scaffolds which are regarded as an eligible engineer tissue for bone repair. However, hydrogel is still limited in improving neovascularization.Methods: In this work, black phosphorus nanosheet and deferoxamine (BPN-DFO) were loaded in the gelatin hydrogel to overcome the high risk of bone delay union and systemically investigated the regeneration capability of BPN-DFO hydrogel in vitro and vivo.Results: The resulting BPN-DFO hydrogel scaffold showed superior swollen, degradation and release rate, as well as satisfied biocompatibility. BPN-DFO hydrogel shown the significant up-expression of mRNA related to bone regeneration and cell proliferation. In vivo, the proposed BPN-DFO hydrogel significantly improved osteogenesis and neovascularization in the ischemic tibial bone site of SD rats with acute femoral artery occlusion. Both macroscopic and histological evaluation of new regenerated bone showed newly formed blood vessel and collagen using BPN-DFO hydrogel. The immunohistochemistry and RT-PCR revealed that the bone regeneration could be improved via BMP/Runx2 pathway.Conclusion: The BPN-DFO hydrogel possesses potential tissue engineer material for ischemic bone defect treatment. However, furthermore studies are needed to testify the safety and efficacy of BPN-DFO hydrogel.Keywords: ischemic bone defect regeneration, hydrogel scaffolds, black phosphorus nanosheets, deferoxamine