Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea; Convergence Institute of Biomedical Engineering and Biomaterials, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea.
Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea.
Mater Sci Eng C Mater Biol Appl. 2020 Aug;113:111008. doi: 10.1016/j.msec.2020.111008. Epub 2020 Apr 24.
In this study, carboxymethyl cellulose (CMC)-glycol chitosan (GC) hydrogel, a potential three-dimensional (3D) printing biomaterial ink for tissue engineering applications was synthesized using simple, biocompatible in situ-gelling Schiff's base reaction and ionic interactions. Different grades of hydrogels (C70G30, C50G50 and C30G70) were synthesized at physiological conditions. The oxidation of CMC and imine bond formation in the hydrogel were confirmed spectroscopically. Scanning electron microscopic images revealed the crosslinked interconnected pores in the cross-sectioned hydrogels (dried). Swelling (equilibrium: 1 h), porosity (~75%), in vitro degradation (>30 days) and thermal gravimetric analyses of the dried gels were studied. Initially, cytotoxicity assay was evaluated using mouse osteoblastic cells (MC3T3). These experiments revealed that CMC-GC gels formed stable hydrogel networks and were biocompatible. Particularly, C50G50 gels showed high printability (continuous extrusion) and post-printing stability (without secondary crosslinking). Gel 3D printing was optimized by varying the air pressure, temperature, needle size and nozzle speed, to obtain stable lattice structures (2 to 16 layers). The printed (2 and 5 layers) hydrogels showed high stability in phosphate buffer saline (PBS) solution (1 h), under UV light (1 h) and after autoclaving. The strut dimensions and porosity of the printed gels before and after the stability tests were analyzed. The hydrogel stability may be attributed to both the imine bond and ionic interaction between the cationic and anionic polymer side chains. Lactoferrin (glycoprotein) incorporated C50G50 gels showed sustained release up to 21 days in PBS (pH 7.4) solution and demonstrated increased biocompatibility (>80%) during in vitro cytotoxicity assays (MC3T3 cells and bone marrow mesenchymal stem cells) and Live/Dead assay (MC3T3 cells). A higher number of live osteoblast cells on the C50G50 hydrogels with increasing lactoferrin concentration was observed. These results show that the CMC-GC gels are promising bio-ink candidates for 3D printing and loading proteins or drugs for tissue engineering applications.
在这项研究中，羧甲基纤维素（CMC）- 乙二醇壳聚糖（GC）水凝胶是一种潜在的三维（3D）打印生物材料墨水，可用于组织工程应用，它是使用简单、生物相容的原位凝胶希夫碱反应和离子相互作用合成的。在生理条件下合成了不同等级的水凝胶（C70G30、C50G50 和 C30G70）。通过光谱学证实了 CMC 的氧化和水凝胶中亚胺键的形成。扫描电子显微镜图像显示了横截面水凝胶（干燥）中的交联互穿孔。研究了水凝胶的溶胀（平衡：1 h）、孔隙率（~75%）、体外降解（>30 天）和干燥凝胶的热重分析。最初，使用小鼠成骨细胞（MC3T3）评估了细胞毒性试验。这些实验表明 CMC-GC 水凝胶形成了稳定的水凝胶网络，具有生物相容性。特别是，C50G50 水凝胶显示出高可打印性（连续挤出）和打印后稳定性（无需二次交联）。通过改变气压、温度、针头尺寸和喷嘴速度来优化水凝胶 3D 打印，以获得稳定的晶格结构（2 至 16 层）。在磷酸盐缓冲盐水（PBS）溶液（1 h）、紫外光（1 h）和高压灭菌后，打印（2 和 5 层）水凝胶显示出很高的稳定性。在稳定性测试前后分析了打印水凝胶的支柱尺寸和孔隙率。水凝胶的稳定性可能归因于阳离子和阴离子聚合物侧链之间的亚胺键和离子相互作用。负载乳铁蛋白（糖蛋白）的 C50G50 水凝胶在 PBS（pH 7.4）溶液中可实现长达 21 天的持续释放，并在体外细胞毒性试验（MC3T3 细胞和骨髓间充质干细胞）和 Live/Dead 试验（MC3T3 细胞）中显示出更高的生物相容性（>80%）。随着乳铁蛋白浓度的增加，在 C50G50 水凝胶上观察到更多的活成骨细胞。这些结果表明，CMC-GC 水凝胶是 3D 打印的有前途的生物墨水候选物，可用于组织工程应用中负载蛋白质或药物。
