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.

中文翻译：

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3D 生物打印的载有细胞的多孔支架中的藻酸盐依赖性物理特性变化会影响细胞活力和细胞形态。

三维（3D）细胞负载支架在骨组织修复和再生中变得越来越普遍。然而，物理支架特性对细胞行为的影响仍不清楚。在这项研究中，我们使用 3D 生物打印技术制造了四种不同藻酸盐浓度（0.8、1.3、1.8 和 2.3% alg）的复合细胞负载多孔支架。目的是研究海藻酸盐浓度对物理性质的变化以及对细胞行为的影响。研究表明，不同海藻酸盐浓度的支架具有均匀的大孔（500-600μm），压缩模量范围为1.5 kPa（0.8％alg）至14.2 kPa（2.3％alg）。当在细胞培养基中培养时，打印支架可以实现长期结构完整性，但在磷酸盐缓冲盐水（PBS）中培养时则无法实现。支架结构、膨胀行为和压缩模量随着培养时间的延长而降低，并且较高的藻酸盐浓度导致更稳定的物理支架性能。同时，制造了载有人类间充质干细胞（hMSC）的非印刷和生物印刷复合支架。生物打印不影响细胞活力，但藻酸盐浓度对细胞活力和细胞形态有显着影响。第 14 天时，与较高藻酸盐浓度支架 (2.3% alg) 相比，较低藻酸盐浓度支架 (0.8% alg) 显示出更高的细胞活力（84% ± 0.7% 与 68% ± 1.3%）。0.8% alg 支架中的活细胞图像证明了 3D 互连细胞网络的形成，而 1.8% 和 2.3% alg 支架中的细胞形成球体。总之，这项研究拓宽了用于 3D 生物打印的海藻酸盐生物墨水的设计空间。较高的藻酸盐浓度保留了更好的支架保真度和机械性能。在较低藻酸盐浓度的支架中实现了更好的细胞活力和细胞铺展形态，这与骨组织工程中的潜在应用相关。