Departamento de Ingeniería Química, Biotecnología y Materiales, Facultad de Ciencias Físicas y Matemáticas , Universidad de Chile , Beauchef 851 , 8370456 Santiago , Chile.
Institute for Technical Chemistry and Polymer Chemistry (ITCP) , Karlsruhe Institute of Technology (KIT) , Engesserstr. 18 , 76131 Karlsruhe , Germany.
ACS Appl Mater Interfaces. 2020 Jan 29;12(4):4343-4357. doi: 10.1021/acsami.9b22062. Epub 2020 Jan 17.
Scaffolds based on bioconjugated hydrogels are attractive for tissue engineering because they can partly mimic human tissue characteristics. For example, they can further increase their bioactivity with cells. However, most of the hydrogels present problems related to their processability, consequently limiting their use in 3D printing to produce tailor-made scaffolds. The goal of this work is to develop bioconjugated hydrogel nanocomposite inks for 3D printed scaffold fabrication through a micro-extrusion process having improved both biocompatibility and processability. The hydrogel is based on a photocrosslinkable alginate bioconjugated with both gelatin and chondroitin sulfate in order to mimic the cartilage extracellular matrix, while the nanofiller is based on graphene oxide to enhance the printability and cell proliferation. Our results show that the incorporation of graphene oxide into the hydrogel inks considerably improved the shape fidelity and resolution of 3D printed scaffolds because of a faster viscosity recovery post extrusion of the ink. Moreover, the nanocomposite inks produce anisotropic threads after the 3D printing process because of the templating of the graphene oxide liquid crystal. The in vitro proliferation assay of human adipose tissue-derived mesenchymal stem cells (hADMSCs) shows that bioconjugated scaffolds present higher cell proliferation than pure alginate, with the nanocomposites presenting the highest values at long times. Live/Dead assay otherwise displays full viability of hADMSCs adhered on the different scaffolds at day 7. Notably, the scaffolds produced with nanocomposite hydrogel inks were able to guide the cell proliferation following the direction of the 3D printed threads. In addition, the bioconjugated alginate hydrogel matrix induced chondrogenic differentiation without exogenous pro-chondrogenesis factors as concluded from immunostaining after 28 days of culture. This high cytocompatibility and chondroinductive effect toward hADMSCs, together with the improved printability and anisotropic structures, makes these nanocomposite hydrogel inks a promising candidate for cartilage tissue engineering based on 3D printing.
基于生物共轭水凝胶的支架在组织工程中很有吸引力，因为它们可以部分模拟人体组织的特性。例如，它们可以通过细胞进一步提高其生物活性。然而，大多数水凝胶存在与加工相关的问题，因此限制了它们在 3D 打印中用于生产定制支架的用途。本工作的目的是开发用于 3D 打印支架制造的生物共轭水凝胶纳米复合油墨，通过微挤压工艺提高生物相容性和加工性。该水凝胶基于光交联的藻酸盐，与明胶和硫酸软骨素共轭，以模拟软骨细胞外基质，而纳米填料基于氧化石墨烯，以提高可印刷性和细胞增殖。我们的结果表明，氧化石墨烯的加入极大地改善了水凝胶油墨的形状保真度和 3D 打印支架的分辨率，因为油墨挤出后粘度恢复更快。此外，纳米复合油墨在 3D 打印后产生各向异性的纤维，因为氧化石墨烯的液晶起到了模板的作用。人脂肪组织来源间充质干细胞（hADMSCs）的体外增殖试验表明，生物共轭支架的细胞增殖率高于纯藻酸盐支架，而纳米复合材料在长时间内具有最高的增殖率。活/死试验则显示，hADMSCs 在不同支架上的黏附率在第 7 天达到 100%。值得注意的是，用纳米复合水凝胶油墨制造的支架能够沿着 3D 打印纤维的方向引导细胞增殖。此外，生物共轭藻酸盐水凝胶基质在没有外源性促软骨形成因子的情况下诱导了软骨分化，这可以从培养 28 天后的免疫染色中得出结论。这些高度的细胞相容性和对 hADMSCs 的软骨诱导作用，加上可提高的印刷性能和各向异性结构，使得这些纳米复合水凝胶油墨成为基于 3D 打印的软骨组织工程的有前途的候选材料。
