Mechanical Interlocking of Engineered Cartilage to an Underlying Polymeric Substrate: Towards a Biohybrid Tissue Equivalent
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This study investigates the feasibility of engineering a biohybrid cartilage equivalent (BCE) with the long-term goal of restoring the mechanical integrity and interfacial characteristics of severely damaged cartilage. The BCE depends on the successful adhesion, via mechanical interlocking, of a cartilage layer to a nondegradable composite scaffold or prosthesis. The model scaffold, consisting of a nonwoven mesh bonded to a solid core, was seeded with bovine articular chondrocytes. High molecular weight poly(l-lactic acid), which has a slow degradation time, was used to model the nondegradable polymer. Biochemical and histological analysis demonstrate that the BCE can support the growth of a cartilaginous matrix for at least 6 weeks in culture. Mechanical testing of the BCE showed cartilage adhesion strength increased from 19.27±1.62 to 43.79±3.88 kPa between 35 and 50 days in culture. Nonmechanically interlocked cartilage achieved less than 5% of this adhesion strength. For the first time, atomic force microscopy (AFM) was used to characterize surface topography of tissue-engineered cartilage. Surface roughness of constructs after 8 and 10 weeks ranged from 153 to 171 nm, falling within the range of native cartilage (100–600 nm). This study demonstrates the feasibility of creating a biohybrid cartilage equivalent by mechanically interlocking a cartilaginous layer to an underlying polymeric matrix.
KeywordsCartilage Tissue engineering Cell functionalization Biolayer Prosthesis Lubrication Cell adhesion Chondrocytes
This research was supported by the AO Research Foundation. We thank Dr. Gajendra Shekhawat for his help in obtaining AFM images as well as Evanston Hospital and Northwestern Memorial Hospital for histological sectioning and staining expertise. We also thank Swissland Packing Co. for donating the bovine knees.
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