Mimicked Hydrogels for Bone Tissue Engineering in Orthopedic Applications

Abstract

In this study, mimicked hydrogels are designed and fabricated for bone tissue engineering in orthopedic applications. Hydrogels in this research are used for 1) the model for diseases evaluation 2) biomaterial for surgery in bone tissue regeneration and 3) biomaterial for morphological formation of tissue. The first study is to fabricate hydrogels as model for evaluation of heterotopic ossification. Gelatin/chitosan/CCP was selected for hydrogel fabrication with the mimicking. The results showed that the mimicked gelatin/chitosan/CCP hydrogels had the suitable structure, physical and biological functionality for a model to evaluate heterotopic ossification. The second part is to fabricate and apply hydrogels for surgery to regenerate tissue at subchondral bone interface. Gelatin/PVA was fabricated into hydrogel based on the mimicking. The mimicked gelatin/PVA hydrogel demonstrated the good biological performance; cell adhesion and proliferation, the biomarkers referred to bone regeneration. This showed that the mimicked gelatin/PVA hydrogel for surgery to regenerate tissue at the subchondral bone interface. The third part is to synthesize the grafted hyaluronic acid (HA)-poly (N-isopropylacrylamide) (PNIPAM-COOH) thermo-responsive polymer via polymerization. This copolymer was created based on mimicked extracellular matrix (ECM) component of HA which had the thermo-responsive function of PNIPAM. The two dimensional (2D) hydrogel of HA-PNIPAM was used as substrate of the basement membrane ECM for morphological formation of cell sheet. The results demonstrate that cells well adhered, proliferated, and regulated into sheet on the substrate. This cell sheet is promising to tissue regeneration at the subchondrol bone. Furthermore, the cell sheet on substrate was detached and self-organized into the rolled form. This is the trigger idea as the model to engineer the complicate morphology of tissue for the future works. This research demonstrated that the mimicked hydrogel had the potential for orthopedic applications.