Surface-Modified Nano-Hydroxyapatite Uniformly Dispersed on High-Porous GelMA Scaffold Surfaces for Enhanced Osteochondral Regeneration

Abstract

Suyang Zheng,1,* Dong Li,1,2,* Qingbai Liu,1,3 Cheng Tang,1 Wenhao Hu,1,4 Shengshan Ma,1,5 Yan Xu,1,6,7 Yong Ma,8 Yang Guo,8 Bo Wei,1 Chuanlin Du,9 Liming Wang1,6,7 1Department of Orthopedics, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, People’s Republic of China; 2Department of Trauma Center, The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, Jiangsu Province, People’s Republic of China; 3Department of Orthopedics, Lianshui People’s Hospital of Kangda College Affiliated to Nanjing Medical University, Huai’an, Jiangsu Province, People’s Republic of China; 4Department of Orthopedics, The Affiliated Huai’an No.1 People’s Hospital of Nanjing Medical University, Huai’an, Jiangsu Province, People’s Republic of China; 5Department of Sports Medicine, The First People’s Hospital of Lianyungang, The Affiliated Lianyungang Hospital of Xuzhou Medical University, Lianyungang, Jiangsu Province, People’s Republic of China; 6Key Laboratory of Additive Manufacturing Technology, Institute of Digital Medicine, Nanjing Medical University, Nanjing, Jiangsu Province, People’s Republic of China; 7Cartilage Regeneration Center, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, People’s Republic of China; 8Laboratory of New Techniques of Restoration and Reconstruction of Orthopedics and Traumatology, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, People’s Republic of China; 9Department of Orthopedics, Ganyu District People’s Hospital of Lianyungang, Lianyungang, Jiangsu Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Liming Wang; Chuanlin Du, Tel [phone], Fax [phone], Email [email protected]; [email protected]: This study aims to investigate the impact of enhancing subchondral bone repair on the efficacy of articular cartilage restoration, thereby achieving improved osteochondral regeneration outcomes.Methods: In this study, we modified the surface of nano-hydroxyapatite (n-HAp) through alkylation reactions to prepare n-HApMA. Characterization techniques, including X-ray diffraction, infrared spectroscopy scanning, thermogravimetric analysis, particle size analysis, and electron microscopy, were employed to analyze n-HApMA. Bioinks were prepared using n-HApMA, high porosity GelMA hydrogel, and adipose tissue derived stromal cells (ADSCs). The rheological properties of the bioinks during photocuring were investigated using a rheometer. Based on these bioinks, a biphasic scaffold was constructed. The viability of cells within the scaffold was observed using live-dead cell staining, while the internal morphology was examined using scanning electron microscopy. The stiffness of the scaffold was evaluated through compression testing. Scaffolds were implanted into the osteochondral defects of New Zealand rabbit knees, and microCT was utilized to observe the subchondral bone repair. Hematoxylin and eosin (H&E) staining, Masson’s trichrome staining, and Safranin O/Fast Green staining were performed to assess the regeneration of subchondral bone and cartilage. Furthermore, immunohistochemical staining was employed to detect the expression of osteogenic and chondrogenic-related molecules.Results: Scaffold characterization revealed that surface modification enables the uniform distribution of n-HApMA within the GelMA matrix. The incorporation of 5% n-HApMA notably enhanced the elastic modulus and stiffness of the 6% high-porosity GelMA in comparison to n-HAp. Moreover, in-vivo study showed that the homogeneous dispersion of n-HApMA on the GelMA matrix facilitated the osteogenic differentiation of adipose-derived stem cells (ADSCs) and promoted osteochondral tissue regeneration.Conclusion: These findings suggest potential applications of the n-HApMA/GelMA composite in the field of tissue engineering and regenerative medicine.Graphical Abstract: Keywords: subchondral bone, surface modification, bio-ink, scaffold, hydrogel

Keywords

• subchondral bone
• surface modification
• bio-ink
• scaffold
• hydrogel