Greco Immacolata, Miskovic Vanja, Varon Carolina, Marraffa Chiara, Iorio Carlo S
Université Libre de Bruxelles, Brussels, Belgium.
Front Bioeng Biotechnol. 2022 Jul 8;10:896166. doi: 10.3389/fbioe.2022.896166. eCollection 2022.
Three-dimensional (3D) bio-printing has recently emerged as a crucial technology in tissue engineering, yet there are still challenges in selecting materials to obtain good print quality. Therefore, it is essential to study the influence of the chosen material (i.e., bio-ink) and the printing parameters on the final result. The "printability" of a bio-ink indicates its suitability for bio-printing. Hydrogels are a great choice because of their biocompatibility, but their printability is crucial for exploiting their properties and ensuring high printing accuracy. However, the printing settings are seldom addressed when printing hydrogels. In this context, this study explored the printability of double network (DN) hydrogels, from printing lines (1D structures) to lattices (2D structures) and 3D tubular structures, with a focus on printing accuracy. The DN hydrogel has two entangled cross-linked networks and a balanced mechanical performance combining high strength, toughness, and biocompatibility. The combination of poly (ethylene glycol)-diacrylate (PEDGA) and sodium alginate (SA) enables the qualities mentioned earlier to be met, as well as the use of UV to prevent filament collapse under gravity. Critical correlations between the printability and settings, such as velocity and viscosity of the ink, were identified. PEGDA/alginate-based double network hydrogels were explored and prepared, and printing conditions were improved to achieve 3D complex architectures, such as tubular structures. The DN solution ink was found to be unsuitable for extrudability; hence, glycerol was added to enhance the process. Different glycerol concentrations and flow rates were investigated. The solution containing 25% glycerol and a flow rate of 2 mm/s yielded the best printing accuracy. Thanks to these parameters, a line width of 1 mm and an angle printing inaccuracy of less than 1° were achieved, indicating good shape accuracy. Once the optimal parameters were identified, a tubular structure was achieved with a high printing accuracy. This study demonstrated a 3D printing hydrogel structure using a commercial 3D bio-printer (REGEMAT 3D BIO V1) by synchronizing all parameters, serving as a reference for future more complex 3D structures.
三维（3D）生物打印最近已成为组织工程中的一项关键技术，但在选择材料以获得良好的打印质量方面仍存在挑战。因此，研究所选材料（即生物墨水）和打印参数对最终结果的影响至关重要。生物墨水的“可打印性”表明其适用于生物打印。水凝胶因其生物相容性而成为一个很好的选择，但其可打印性对于发挥其性能和确保高打印精度至关重要。然而，在打印水凝胶时很少涉及打印设置。在此背景下，本研究探讨了双网络（DN）水凝胶从打印线条（一维结构）到晶格（二维结构）和三维管状结构的可打印性，重点关注打印精度。DN水凝胶具有两个缠结的交联网络，以及结合了高强度、韧性和生物相容性的平衡机械性能。聚（乙二醇）-二丙烯酸酯（PEDGA）和海藻酸钠（SA）的组合能够满足上述特性，同时利用紫外线防止细丝在重力作用下坍塌。确定了可打印性与设置之间的关键相关性，如墨水的速度和粘度。对基于PEGDA/藻酸盐的双网络水凝胶进行了探索和制备，并改进了打印条件以实现三维复杂结构，如管状结构。发现DN溶液墨水不适合挤出性；因此，添加甘油以改进该过程。研究了不同的甘油浓度和流速。含有25%甘油且流速为2毫米/秒的溶液产生了最佳的打印精度。由于这些参数，实现了1毫米的线宽和小于1°的角度打印误差，表明形状精度良好。一旦确定了最佳参数，就以高打印精度实现了管状结构。本研究通过同步所有参数，展示了使用商用3D生物打印机（REGEMAT 3D BIO V1）打印水凝胶结构，为未来更复杂的三维结构提供了参考。
