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Several studies have shown how different cell lines can influence the differentiation of stem cells through co-culture systems. The House Ear Institute-Organ of Corti 1 (HEI-OC1) is considered an important cell line for in vitro auditory research. However, it is unknown if HEI-OC1 cells can promote the differentiation of embryonic stem cells (ESCs). In this study, we investigated whether co-culture of ESCs with HEI-OC1 cells promotes differentiation. To this end, we developed a co-culture system of mouse ESCs with HEI-OC1 cells. Dissociated or embryonic bodies (EBs) of ESCs were introduced to a conditioned and inactivated confluent layer of HEI-OC1 cells for 14 days. The dissociated ESCs coalesced into an EB-like form that was smaller than the co-cultured EBs. Contact co-culture generated cells expressing several otic progenitor markers as well as hair cell specific markers. ESCs and EBs were also cultured in non-contact setup but using conditioned medium from HEI-OC1 cells, indicating that soluble factors alone could have a similar effect. The ESCs did not form into aggregates but were still Myo7a-positive, while the EBs degenerated. However, in the fully differentiated EBs, evidence to prove mature differentiation of inner ear hair cell was still rudimentary. Nevertheless, these results suggest that cellular interactions between ESCs and HEI-OC1 cells may both stimulate ESC differentiation.

Surface modification is one important way to fabricate successful biocompatible materials in bone tissue engineering. Hydroxyapatite (HAp) materials have received considerable attention as suitable bioceramics for manufacturing osseous implants because of their similarity to bone mineral in terms of chemical composition. In this study, the surface of porous HAp scaffold was modified by collagen treatment and bone morphogenetic protein-2 (BMP-2) conjugation. The surface modification did not affect the HAp scaffold's bulk properties. No significant difference in compressive strength was found among different scaffolds, with HAp, collagen modified HAp, and collagen-BMP-2-functionalized HAp having compressive strengths of 45.8 ± 3.12, 51.2 ± 4.09, and 50.7 ± 3.98 MPa, respectively. In vitro studies were performed to compare adhesion and osteogenic differentiation between human adipose-derived stem cells (hADSCs) with modified surfaces and those unmodified HAp surfaces. Collagen or BMP-2 alone was insufficient and that both collagen and BMP-2 are necessary to get the desired results. The findings suggest the possibility of using three-dimensional HAp scaffold treated with gold-standard collagen coating and highly researched BMP-2 growth factor as a platform to deliver hADSCs. Results of this study could be used to develop treatment strategy for regenerating completely transected models using more synergistic approaches., (© 2019 Wiley Periodicals, Inc.)

Studies have shown the technological and functional properties of ovomucin (OVN) in the food-agricultural industry. But research has yet to explore its potential as an implantable biomaterial for tissue engineering and regenerative medicine. In this study we isolated OVN from egg white by isoelectric precipitation and fabricated scaffolds with tunable porosity by utilizing its foaming property. Gelatin a known biocompatible material was introduced to stabilize the foams, wherein different ratios of OVN and gelatin had a significant effect on the degree of porosity, pore size and stability of the formed hydrogels. The porous scaffolds were crosslinked with EDC resulting in stable scaffolds with prolonged degradation. Improved cell proliferation and adhesion of rat bone marrow-derived mesenchymal stem cells were observed for OVN containing scaffolds. Although, scaffolds with 75% OVN showed decrease in cell proliferation for L929 fibroblast type of cells. Further biocompatibility assessment as implant material was determined by subcutaneous implantation in rats of selected scaffold. H&E staining showed reasonable vascularization over time and little evidence of severe fibrosis at the implant site. Persistent polarization of classically activated macrophage was not observed, potentially reducing inflammatory response, and showed increased expression of alternatively activated macrophage cells that is favorable for tissue repair. Analysis of IgE levels in rat serum after implantation indicated minimal and resolvable allergic response to the OVN implants. The results demonstrate OVN as an acceptable implant scaffold that could provide new opportunities as an alternative natural biocompatible and functional biomaterial in various biomedical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2107-2117, 2017., (© 2016 Wiley Periodicals, Inc.)

Nonunion associated with long bone defects continues to be highly researched both experimentally and clinically. A porous hydroxyapatite (HAp) scaffold has been recognized as a bone repair and substitute material clinically, but its use in segmental bone defects has been limited by poor integration and stability, as a consequence of scaffold strength unmatched with the native bone. Herein, we designed a multi-channel HAp-based scaffold for application in segmental bone defects, with a specific geometry and design. It possesses the required porosity for bone tissue regeneration with sufficient mechanical properties. We also developed a surface functionalization/modification method with the goal of early scaffold integration and stability. Initial functionalization with poly(vinyl phosphonic acid), PVPA, allowed simple attachment of a chitosan polymeric layer. The modification improved the biocompatibility of the scaffold and attachment of rat bone marrow-derived mesenchymal stem cells (rBMSC) in vitro. The modification also served as a buffer between the implant scaffold and bone tissue. Significant improvement in the integration behavior with better interlocking of the scaffold to bone tissue was observed for the modified scaffolds implanted in rabbit tibiae. The modified HAp scaffolds exhibited early interfacial implant-bone tissue integration with enhanced new bone formation and high potential for use in segmental bone defects.