Pacelli Settimio, Basu Sayantani, Berkland Cory, Wang Jinxi, Paul Arghya
BioIntel Research Laboratory, Department of Chemical and Petroleum Engineering, Bioengineering Graduate Program, School of Engineering, University of Kansas, Lawrence, KS 66045 USA.
Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047 USA.
Cell Mol Bioeng. 2018 Jun;11(3):211-217. doi: 10.1007/s12195-018-0521-3. Epub 2018 Apr 6.
Physical and mechanical properties of ceramic-based scaffolds can be modulated by introducing hydrogel coatings on their surface. For instance, hydrogels can be used as elastic layers to overcome the brittleness of synthetic ceramic materials or to control the delivery of essential osteogenic factors. In this work, we aimed to achieve both goals by fabricating a novel cytocompatible hydrogel made of gelatin-alginate as a coating for beta-tricalcium phosphate (β-TCP) scaffolds.
The hydrogel synthesis was optimized by varying the concentration of the crosslinkers N-hydroxysuccinimide and N-Ethyl-N'-(3-dimethyl aminopropyl) carbodiimide (NHS/EDC). Swelling, degradability and mechanical studies were carried out to identify the suitable hydrogel coating formulation for the β-TCP scaffolds. The cytocompatibility of the coated ceramic was assessed by testing the proliferation and the osteogenic differentiation of human adipose stem cell (hASCs) for two weeks.
The designed hydrogel layer could withstand cyclic compression and protected the brittle internal core of the ceramic. The hydrogel coating modulated the diffusion of the model protein BSA according to the degree of crosslinking of the hydrogel layer. Additionally, the polymeric network was able to retain positively charged proteins such as lysozyme due to the strong electrostatic interactions with carboxylic groups of alginate. A higher expression of alkaline phosphates activity was found on hASCs seeded on the coated scaffolds compared to the hydrogels without any β-TCP.
Overall, the hydrogel coating characterized in this study represents a valid strategy to overcome limitations of brittle ceramic-based materials used as scaffolds for bone tissue engineering applications.
通过在陶瓷基支架表面引入水凝胶涂层，可以调节其物理和机械性能。例如，水凝胶可以用作弹性层，以克服合成陶瓷材料的脆性或控制必需的成骨因子的递送。在这项工作中，我们旨在通过制备一种由明胶-藻酸盐制成的新型细胞相容性水凝胶作为β-磷酸三钙（β-TCP）支架的涂层来实现这两个目标。
通过改变交联剂N-羟基琥珀酰亚胺和N-乙基-N'-(3-二甲基氨基丙基)碳二亚胺（NHS/EDC）的浓度来优化水凝胶的合成。进行了溶胀、降解性和力学研究，以确定适合β-TCP支架的水凝胶涂层配方。通过测试人脂肪干细胞（hASCs）两周的增殖和成骨分化来评估涂层陶瓷的细胞相容性。
设计的水凝胶层能够承受循环压缩，并保护陶瓷的脆性内核。水凝胶涂层根据水凝胶层的交联程度调节模型蛋白牛血清白蛋白（BSA）的扩散。此外，由于与藻酸盐的羧基有强静电相互作用，聚合物网络能够保留带正电荷的蛋白质，如溶菌酶。与没有任何β-TCP的水凝胶相比，在接种于涂层支架上的hASCs上发现碱性磷酸酶活性有更高的表达。
总体而言，本研究中表征的水凝胶涂层是一种有效的策略，可以克服用作骨组织工程支架的脆性陶瓷基材料的局限性。
