Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093 Zurich, Switzerland.
Biomed Mater. 2019 Sep 25;14(6):065009. doi: 10.1088/1748-605X/ab3c74.
Three-dimensional (3D) cell-laden scaffolds are becoming more prevalent in bone tissue repair and regeneration. However, the influence of physical scaffold properties on cell behavior is still unclear. In this study, we fabricated four different alginate concentration (0.8, 1.3, 1.8 and 2.3%alg) composite cell-laden porous scaffolds using a 3D bioprinting technique. The aim was to investigate the changes of physical properties affected by the alginate concentration and the influences on cell behavior. The study showed that the different alginate concentration scaffolds had uniform macropores (500-600 μm) with compressive moduli ranging from 1.5 kPa (0.8%alg) to 14.2 kPa (2.3%alg). Long-term structural integrity of the printed scaffolds was achieved when cultured in cell culture media, but not when cultured in phosphate buffered saline (PBS). Scaffold structure, swelling behavior, and compressive moduli decreased with culturing time and higher alginate concentration lead to more stable physical scaffold properties. Meanwhile, human mesenchymal stem cell (hMSCs) laden non-printed and bioprinted composite scaffolds were fabricated. Bioprinting did not affect cell viability, but alginate concentration had a significant influence on cell viability and cell morphology. Lower alginate concentration scaffolds (0.8%alg) showed higher cell viability (84% ± 0.7% versus 68% ± 1.3%) compared to higher alginate concentration scaffolds (2.3%alg) at day 14. Live cell image in the 0.8%alg scaffolds demonstrated the formation of a 3D interconnected cellular network, while cells in the 1.8 and 2.3%alg scaffolds formed spheroids. In conclusion, this study broadens the design space for alginate-based bioinks for 3D bioprinting. Higher alginate concentration preserved better scaffold fidelity and mechanical properties. Better cell viability and cell spreading morphology was achieved in lower alginate concentration scaffolds, which is relevant for potential applications in bone tissue engineering.
三维（3D）细胞负载支架在骨组织修复和再生中越来越普遍。然而，物理支架特性对细胞行为的影响尚不清楚。在这项研究中，我们使用 3D 生物打印技术制造了四种不同海藻酸钠浓度（0.8%、1.3%、1.8%和 2.3%alg）的复合细胞负载多孔支架。目的是研究受海藻酸钠浓度影响的物理性质变化及其对细胞行为的影响。研究表明，不同海藻酸钠浓度的支架具有均匀的大孔（500-600μm），压缩模量范围从 1.5kPa（0.8%alg）到 14.2kPa（2.3%alg）。当在细胞培养基中培养时，打印支架可以长期保持结构完整性，但在磷酸盐缓冲盐水（PBS）中培养时则不行。支架结构、溶胀行为和压缩模量随培养时间的延长而降低，较高的海藻酸钠浓度导致物理支架性质更稳定。同时，制备了负载人骨髓间充质干细胞（hMSCs）的非打印和生物打印复合支架。生物打印不影响细胞活力，但海藻酸钠浓度对细胞活力和细胞形态有显著影响。与较高海藻酸钠浓度的支架（2.3%alg）相比，较低海藻酸钠浓度的支架（0.8%alg）在第 14 天显示出更高的细胞活力（84%±0.7%对 68%±1.3%）。0.8%alg 支架中的活细胞图像显示出三维相互连接的细胞网络的形成，而 1.8%和 2.3%alg 支架中的细胞形成了球体。总之，这项研究拓宽了用于 3D 生物打印的海藻酸钠基生物墨水的设计空间。较高的海藻酸钠浓度保持了更好的支架保真度和机械性能。在较低的海藻酸钠浓度支架中实现了更好的细胞活力和细胞扩展形态，这与骨组织工程的潜在应用相关。
