School of Biomolecular and Biomedical Science, University College Dublin, Belfield Dublin 4, Ireland.
School of Physics, University College Dublin, Belfield Dublin 4, Ireland.
Biomed Mater. 2024 Jun 10;19(4). doi: 10.1088/1748-605X/ad51bf.
Three-dimensional (3D) (bio)printing technology has boosted the advancement of the biomedical field. However, tissue engineering is an evolving field and (bio)printing biomimetic constructions for tissue formation is still a challenge. As a new methodology to facilitate the construction of more complex structures, we suggest the use of the fluid-phase 3D printing to pattern the scaffold's properties. The methodology consists of an exchangeable fluid-phase printing medium in which the constructions are fabricated and patterned during the printing process. Using the fluid-phase methodology, the biological and mechanical properties can be tailored promoting cell behaviour guidance and compartmentalization. In this study, we first assessed different formulations of alginate/gelatin to create a stable substrate capable to promote massive cell colonizationover time. Overall, formulations with lower gelatin content and 2-(N-morpholino)ethanesulfonic acid (MES) buffer as a solvent showed better stability under cell culture conditions and enhanced U2OS cell growth. Next, the fluid-phase showed better printing fidelity and resolution in comparison to air printing as it diminished the collapsing and the spread of the hydrogel strand. In sequence, the fluid-phase methodology was used to create functionalized alginate-gelatin-arginylglycylaspartic acid peptide (RGD) hydrogels via carbodiimides chemistry. The alginate-gelatin-RGD hydrogels showed an increase of 2.97-fold in cell growth and more spread substrate colonization in comparison to alginate-gelatin hydrogel. Moreover, the fluid-phase methodology was used to add RGD molecules to pre-determined parts of the alginate-gelatin substrate during the printing process promoting U2OS cell compartmentalization. In addition, different substrate stiffnesses were also created via fluid-phase by crosslinking the hydrogel with different concentrations of CaClduring the printing process. As a result, the U2OS cells were also compartmentalized on the stiffer parts of the printings. Finally, our results showed that by combining stiffer hydrogel with RGD increasing concentrations we can create a synergetic effect and boost cell metabolism by up to 3.17-fold. This work presents an idea of a new printing process for tailoring multiple parameters in hydrogel substrates by using fluid-phase to generate more faithful replication of theenvironment.
三维(3D)(生物)打印技术推动了生物医学领域的发展。然而,组织工程是一个不断发展的领域,为组织形成而打印仿生结构仍然是一个挑战。作为一种促进更复杂结构构建的新方法,我们建议使用流体相 3D 打印来对支架的性能进行图案化。该方法包括可交换的流体相打印介质,其中在打印过程中构建和图案化构造。使用流体相方法,可以定制生物和机械性能,从而促进细胞行为指导和分隔。在这项研究中,我们首先评估了不同配方的海藻酸盐/明胶,以创建一种能够随时间促进大量细胞定植的稳定基质。总体而言,含有较低明胶含量和 2-(N-吗啉基)乙磺酸(MES)缓冲液作为溶剂的配方在细胞培养条件下表现出更好的稳定性,并增强了 U2OS 细胞的生长。接下来,与空气打印相比,流体相显示出更好的打印保真度和分辨率,因为它减少了水凝胶链的坍塌和扩散。随后,通过碳二亚胺化学,使用流体相方法在海藻酸盐-明胶-精氨酸-甘氨酸-天冬氨酸肽(RGD)水凝胶上创建功能化水凝胶。与海藻酸盐-明胶水凝胶相比,海藻酸盐-明胶-RGD 水凝胶的细胞生长增加了 2.97 倍,并且基质的细胞定植更加广泛。此外,通过在打印过程中使用流体相将 RGD 分子添加到海藻酸盐-明胶基质的预定部分,使用流体相方法促进了 U2OS 细胞的分隔。此外,还通过在打印过程中用不同浓度的 CaCl2 交联水凝胶来创建不同的基质硬度。结果,U2OS 细胞也在打印件的较硬部分进行了分隔。最后,我们的结果表明,通过将刚性更高的水凝胶与增加浓度的 RGD 结合,我们可以产生协同作用,将细胞代谢提高多达 3.17 倍。这项工作提出了一种新的打印工艺的想法,通过使用流体相在水凝胶基质中产生更多真实的环境复制,从而可以定制多个参数。