End-stage treatment for lager defects, Total Knee Replacement(TKR), demonstrates significant clinical improvement however, due to risk of revision surgery is not preferable for younger patients.Finding new methods for partial or complete resurfacing of synovial joints remains an important challenge. Tissue engineering using scaffold-based technology, although promising alternative approach for repair, is subject to few limitations, such as poor cytocompatibility and degradation associated with toxicity. For that reason, we attempt to engineer a totally scaffold-free functional cartilage construct using a Bio-3D printer based on Kenzan technology.
As a material, we used iPSCs derived neural crest cells (NCC) well known for its potential to undergo chondrogenesis through mesenchymal stem cell differentiation. To engineer the tissue, using Bio-3D printer, iNSMSCs spheroids formed in the chondrogenesis induction medium, were automatically placed by the nozzle in the desired position on the Kenzan which is an array of the fine needles. To evaluate the most optimal time for printing, constructs assembled with spheroid from 3 points of induction were analyzed. Biochemical and mechanical analysis of constructs cultured for different time periods were conducted for maturation time optimization. Geometric-dependent shape tissues were printed using various Kenzans.
By optimizing time of fabrication during chondrogenic induction we were able to assembly highly unified, shape-sustainable, cartilaginous construct in size up to 6cm2 with individually-specific topography. Maturation time optimization revealed that following 3 weeks after printing facilitates self-organization of cells, improving mechanical strength and tissue function. Compression modulus reached a range for native cartilage of 0.88MPa in 5th week of maturation.
Herein, we report engineering functional, scaffold-free constructs which may be sufficient for repair of larger chondral defects by successfully combining iPS cells and Kenzan technology using Bio-3D printer.