Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
Biotechnol Bioeng. 2012 Sep;109(9):2357-68. doi: 10.1002/bit.24488. Epub 2012 Apr 8.
Bioprinting as a promising but unexplored approach for cartilage tissue engineering has the advantages of high throughput, digital control, and highly accurate placement of cells and biomaterial scaffold to the targeted 3D locations with simultaneous polymerization. This study tested feasibility of using bioprinting for cartilage engineering and examined the influence of cell density, growth, and differentiation factors. Human articular chondrocytes were printed at various densities, stimulated transiently with growth factors and subsequently with chondrogenic factors. Samples were cultured for up to 4 weeks to evaluate cell proliferation and viability, mechanical properties, mass swelling ratio, water content, gene expression, ECM production, DNA content, and histology. Bioprinted samples treated with FGF-2/TGF-β1 had the best chondrogenic properties among all groups apparently due to synergistic stimulation of cell proliferation and chondrogenic phenotype. ECM production per chondrocyte in low cell density was much higher than that in high cell seeding density. This finding was also verified by mechanical testing and histology. In conclusion, cell seeding density that is feasible for bioprinting also appears optimal for human neocartilage formation when combined with appropriate growth and differentiation factors.
生物打印作为一种有前途但尚未开发的软骨组织工程方法，具有高通量、数字化控制以及将细胞和生物材料支架高精度地放置到目标 3D 位置的优势，同时进行聚合。本研究测试了生物打印在软骨工程中的可行性，并研究了细胞密度、生长和分化因子的影响。将人关节软骨细胞以不同的密度打印，用生长因子短暂刺激，然后用软骨形成因子刺激。将样本培养长达 4 周，以评估细胞增殖和活力、机械性能、质量肿胀比、含水量、基因表达、细胞外基质 (ECM) 产生、DNA 含量和组织学。用 FGF-2/TGF-β1 处理的生物打印样本在所有组中表现出最佳的软骨形成特性，这显然是由于细胞增殖和软骨形成表型的协同刺激。低细胞密度下每个软骨细胞的 ECM 产生量明显高于高细胞接种密度下的 ECM 产生量。这一发现也通过机械测试和组织学得到了验证。总之，与适当的生长和分化因子结合使用时，生物打印可行的细胞接种密度似乎也是形成人新软骨的最佳密度。
