DataSheet1_Pectin-based bioinks for 3D models of neural tissue produced by a pH-controlled kinetics.PDF

Introduction: In the view of 3D-bioprinting with cell models representative of neural cells, we produced inks to mimic the basic viscoelastic properties of brain tissue. Moving from the concept that rheology provides useful information to predict ink printability, this study improves and expands the potential of the previously published 3D-reactive printing approach by introducing pH as a key parameter to be controlled, together with printing time.
Methods: The viscoelastic properties, printability, and microstructure of pectin gels crosslinked with CaCO3 were investigated and their composition was optimized (i.e., by including cell culture medium, HEPES buffer, and collagen). Different cell models representative of the major brain cell populations (i.e., neurons, astrocytes, microglial cells, and oligodendrocytes) were considered.
Results and Discussion: The outcomes of this study propose a highly controllable method to optimize the printability of internally crosslinked polysaccharides, without the need for additives or post-printing treatments. By introducing pH as a further parameter to be controlled, it is possible to have multiple (pH-dependent) crosslinking kinetics, without varying hydrogel composition. In addition, the results indicate that not only cells survive and proliferate following 3D-bioprinting, but they can also interact and reorganize hydrogel microstructure. Taken together, the results suggest that pectin-based hydrogels could be successfully applied for neural cell culture.

引言：针对采用神经细胞代表性细胞模型开展三维生物打印（3D-bioprinting）的研究场景，本研究制备了可模拟脑组织基础粘弹性特性的打印墨水。基于流变学（rheology）可提供有效信息以预测墨水打印适性的理念，本研究通过将酸碱度（pH）与打印时间一同作为关键可控参数，对此前已发表的三维反应式打印方法进行了改进与潜力拓展。
方法：本研究对碳酸钙（CaCO3）交联果胶凝胶的粘弹性、打印适性与微观结构进行了考察，并对其组分进行了优化，具体包括添加细胞培养基、HEPES缓冲液与胶原蛋白。本研究选取了代表主要脑细胞群的多种细胞模型，即神经元、星形胶质细胞、小胶质细胞与少突胶质细胞。
结果与讨论：本研究结果提出了一种高度可控的方法，可在无需添加助剂或进行打印后处理的前提下，优化内部交联多糖的打印适性。通过将pH作为额外可控参数，无需改变水凝胶组分即可实现多种pH依赖型交联动力学过程。此外，研究结果表明，三维生物打印后的细胞不仅能够存活与增殖，还可与水凝胶相互作用并重塑其微观结构。综合来看，本研究结果证实基于果胶的水凝胶可成功应用于神经细胞培养。