Osteochondral Repair and Electromechanical Evaluation of Custom 3D Scaffold Microstructured by Direct Laser Writing Lithography

Objective. The objective of this study was to assess a novel 3D microstructured scaffold seeded with allogeneic chondrocytes (cells) in a rabbit osteochondral defect model. Design. Direct laser writing lithography in pre-polymers was employed to fabricate custom silicon-zirconium containing hybrid organic-inorganic (HOI) polymer SZ2080 scaffolds of a predefined morphology. Hexagon-pored HOI scaffolds were seeded with chondrocytes (cells), and tissue-engineered cartilage biocompatibility, potency, efficacy, and shelf-life in vitro was assessed by morphological, ELISA (enzyme-linked immunosorbent assay) and PCR (polymerase chain reaction) analysis. Osteochondral defect was created in the weight-bearing area of medial femoral condyle for in vivo study. Polymerized fibrin was added to every defect of 5 experimental groups. Cartilage repair was analyzed after 6 months using macroscopical (Oswestry Arthroscopy Score [OAS]), histological, and electromechanical quantitative potential (QP) scores. Collagen scaffold (CS) was used as a positive comparator for in vitro and in vivo studies. Results. Type II collagen gene upregulation and protein secretion was maintained up to 8 days in seeded HOI. In vivo analysis revealed improvement in all scaffold treatment groups. For the first time, electromechanical properties of a cellular-based scaffold were analyzed in a preclinical study. Cell addition did not enhance OAS but improved histological and QP scores in HOI groups. Conclusions. HOI material is biocompatible for up to 8 days in vitro and is supportive of cartilage formation at 6 months in vivo. Electromechanical measurement offers a reliable quality assessment of repaired cartilage.

Automated summary

This study assessed a novel 3D microstructured scaffold seeded with allogeneic chondrocytes in a rabbit osteochondral defect model, demonstrating its efficacy and biocompatibility in both in vitro and in vivo experiments. The findings showed that the scaffold promoted cartilage repair in vivo, and cell addition enhanced cartilage formation.