Laboratory of Tissue Engineering, Korea Institute of Radiological and Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul 01812, Korea.
Program in Biomicro System Technology, Korea University, Innovation Hall, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Korea.
Int J Mol Sci. 2021 Oct 27;22(21):11600. doi: 10.3390/ijms222111600.
Gelatin has excellent biological properties, but its poor physical properties are a major obstacle to its use as a biomaterial ink. These disadvantages not only worsen the printability of gelatin biomaterial ink, but also reduce the dimensional stability of its 3D scaffolds and limit its application in the tissue engineering field. Herein, biodegradable suture fibers were added into a gelatin biomaterial ink to improve the printability, mechanical strength, and dimensional stability of the 3D printed scaffolds. The suture fiber reinforced gelatin 3D scaffolds were fabricated using the thermo-responsive properties of gelatin under optimized 3D printing conditions (-10 °C cryogenic plate, 40-80 kPa pneumatic pressure, and 9 mm/s printing speed), and were crosslinked using EDC/NHS to maintain their 3D structures. Scanning electron microscopy images revealed that the morphologies of the 3D printed scaffolds maintained their 3D structure after crosslinking. The addition of 0.5% (/) of suture fibers increased the printing accuracy of the 3D printed scaffolds to 97%. The suture fibers also increased the mechanical strength of the 3D printed scaffolds by up to 6-fold, and the degradation rate could be controlled by the suture fiber content. In in vitro cell studies, DNA assay results showed that human dermal fibroblasts' proliferation rate of a 3D printed scaffold containing 0.5% suture fiber was 10% higher than that of a 3D printed scaffold without suture fibers after 14 days of culture. Interestingly, the supplement of suture fibers into gelatin biomaterial ink was able to minimize the cell-mediated contraction of the cell cultured 3D scaffolds over the cell culture period. These results show that advanced biomaterial inks can be developed by supplementing biodegradable fibers to improve the poor physical properties of natural polymer-based biomaterial inks.
明胶具有优异的生物性能，但较差的物理性能是其作为生物材料墨水应用的主要障碍。这些缺点不仅恶化了明胶生物材料墨水的可印刷性，而且降低了其 3D 支架的尺寸稳定性，并限制了其在组织工程领域的应用。在此，将可生物降解缝线纤维添加到明胶生物材料墨水中，以改善 3D 打印支架的可印刷性、机械强度和尺寸稳定性。利用明胶的温敏特性，在优化的 3D 打印条件下（-10°C 低温板、40-80 kPa 气压和 9 mm/s 打印速度），制备了缝线纤维增强的明胶 3D 支架，并使用 EDC/NHS 进行交联以维持其 3D 结构。扫描电子显微镜图像显示，3D 打印支架的形态在交联后保持其 3D 结构。添加 0.5%（/）缝线纤维可将 3D 打印支架的打印精度提高到 97%。缝线纤维还可将 3D 打印支架的机械强度提高 6 倍，且降解速率可通过缝线纤维含量进行控制。在体外细胞研究中，DNA 分析结果表明，在培养 14 天后，含有 0.5%缝线纤维的 3D 打印支架中人类真皮成纤维细胞的增殖率比不含缝线纤维的 3D 打印支架高 10%。有趣的是，在细胞培养期间，向明胶生物材料墨水中添加缝线纤维能够最大程度地减少细胞培养的 3D 支架的细胞介导收缩。这些结果表明，通过补充可生物降解纤维来改善天然聚合物基生物材料墨水的物理性能，可以开发出先进的生物材料墨水。
