Bi-layered Composite Scaffold for Repair of the Osteochondral Defects

Abstract

Objective: Osteochondral defect presents a big challenge for clinical treatment. This study aimed at constructing a bi-layered composite chitosan/ chitosan-b-tricalcium phosphate (CS/CS-b-TCP) scaffold and at repairing the rat osteochondral defect. Approach: The bi-layered CS/CS-b-TCP scaffold was fabricated by lyophilization, and its microstructure was observed by a scanning electron microscope. Chondrocytes and bone marrow stem cells (BMSCs) were seeded into the CS layer and the CS-b-TCP layer, respectively. Viability and proliferation ability of the cells were observed under a confocal microscope. After subcutaneous implantation, the chondrogenic ability of the CS layer and osteogenic ability of the CS-b-TCP layer were evaluated by immunofluorescence. Then, the bilayered scaffolds were implanted into the rat osteochondral defects and the harvested samples were macroscopically and histologically evaluated. Results: The bi-layered CS/CS-b-TCP scaffold exhibited the distinctive microstructures for each layer. The seeded chondrocytes in the CS layer could maintain the chondrogenic lineage, whereas BMSCs in the CS-b-TCP layer could continually differentiate into the osteogenic lineage. Moreover, cells in both layers could maintain well viability and excellent proliferation ability. For the in vivo study, the newly formed tissues in the bi-layered scaffolds group were similar with the native osteochondral tissues, which comprised hyaline-like cartilage and subchondral bone, with better repair effects compared with those of the pure CS group and the blank control group. Innovation: This is the first time that the bi-layered composite CS/CS-b-TCP scaffold has been fabricated and evaluated with respect to osteochondral defect repair. Conclusion: The bi-layered CS/CS-b-TCP scaffolds could facilitate osteochondral defect repair and might be the promising candidates for osteochondral tissue engineering.

Scaffold-Based Tissue Engineering Strategies for Osteochondral Repair

“…By the thermally-induced phase separation process, a gradient transition zone between the two layers was established, improving the whole stability. A bilayered chitosan/chitosan-β-tricalcium phosphate (CS/CS-β-TCP) composite scaffold was fabricated and evaluated in a rat model ( Xu et al, 2021 ) ( Figure 7C ). Cells seeded in both layers maintained excellent viability and differentiated into chondrogenic and osteogenic lineages, respectively.…”

“…Copyright 2019 by Springer Science + Business Media LLC. (C) Adapted with permission from ref ( Xu et al, 2021 ). Copyright 2021 by Mary Ann Liebert Inc. (D) Adapted with permission from ref ( Chen et al, 2018 ).…”

Material‐Assisted Strategies for Osteochondral Defect Repair

“…A great body of work has been dedicated to the development of hydrogels, which are hydrated polymer networks that best mimic ECM features. [151] To do so, many polymers have been used and can be combined, including polysaccharides (e.g., HA, [115,152] alginate, [118,121] agarose, [100,153] chitosan, [154][155][156] cellulose derivatives [47] ), proteins (e.g., collagen, [120] gelatin, [157,158] silk fibroin, [159] fibrin, [160] ), and synthetic polymers (e.g., polyethylene glycol (PEG)), [161] reflecting the great number of possibilities, but also the lack of clear guidance in the matter.…”

“…However, from a clinical point of view, it does not allow the rapid fabrication of OC implants of any size and shape, limiting its translation. To circumvent this drawback, cutting out or punching the implant at the time of surgery has been proposed; [147,155] yet, the irregularities of OC defect edges make this procedure difficult. Thus, new approaches are needed, and 3D printing is attracting growing attention as a promising alternative.…”

Multiphasic scaffolds for the repair of osteochondral defects: Outcomes of preclinical studies

“…Bone layer with cells accelerated new bone formation in the pores of the tantalum scaffold, with trabecular-looking structure. Xu et al (2021) [ 107 ] Chitosan/β-TCP Chitosan None Rat Knee – femoral trochlear groove 1.5 mm diameter, 3 mm thickness 6, 12 weeks 3 groups: Control (empty), chitosan scaffold, bilayer scaffold Bilayer scaffold almost completely repaired the defect at 12 weeks, showing good integration with surrounding tissue. There was new bone tissue and a limited amount of cartilaginous tissue with expression of collagen type II.…”