Mohan Tamilselvan, Dobaj Štiglic Andreja, Beaumont Marco, Konnerth Johannes, Gürer Fazilet, Makuc Damjan, Maver Uroš, Gradišnik Lidija, Plavec Janez, Kargl Rupert, Stana Kleinschek Karin
Laboratory for Characterisation and Processing of Polymers, Faculty of Mechanical Engineering, University of Maribor, Smetanova Ulica 17, 2000 Maribor, Slovenia.
University of Natural Resources and Life Sciences (BOKU), Institute of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria.
ACS Appl Bio Mater. 2020 Feb 17;3(2):1197-1209. doi: 10.1021/acsabm.9b01099. Epub 2020 Jan 28.
Three-dimensional scaffolds (3D) with controlled shape, dual porosity and long-term mechanical and dimensional stability in biofluids are of interest as biotemplates in tissue engineering. Herein, self-standing and lightweight cellulose-based biogenic scaffolds with a spatially structured morphology, macropores and interconnected micropores were fabricated using a combination of direct ink writing 3D printing and freeze-drying techniques. This was achieved by developing a water-based and low-cost bicomponent ink based on commercially available nanofibrillated cellulose (NFC) and carboxymethyl cellulose (CMC). Physical cross-linking through dehydrothermal treatment significantly increased the surface hardness, indentation modulus, compression strength, as well as the dimensional stability of the scaffolds in biofluids, in comparison to untreated materials. However, no differences in the spectra of solid state nuclear magnetic resonance or infrared were observed for dehydrothermal treated samples, suggesting that the increase of mechanical properties and dimensional stability is based on the physical cross-linking of functional groups both at the interface between NFC and CMC. The supramolecular structure of the polymers was well-preserved as disclosed by X-ray diffraction measurements. The cross-linked scaffolds showed high proliferation, viability, and attachment of human bone tissue derived osteoblast cells (hFOB). The simple and straightforward avenue proposed here for the design of cellulose-based fibrous inks and dual porous scaffolds from the commercially available materials and without the need of any additional cross-linkers should pave the way for the development of implantable, degradable scaffolds and cell-laden biomaterials for bone tissue regeneration and 3D bioprinting applications.
具有可控形状、双孔隙率以及在生物流体中具备长期机械和尺寸稳定性的三维支架（3D），作为组织工程中的生物模板备受关注。在此，通过直接墨水书写3D打印和冷冻干燥技术相结合的方法，制备出了具有空间结构化形态、大孔和相互连通微孔的自立式轻质纤维素基生物支架。这是通过基于市售纳米原纤化纤维素（NFC）和羧甲基纤维素（CMC）开发一种水基且低成本的双组分墨水来实现的。与未处理的材料相比，通过脱水热处理进行的物理交联显著提高了支架在生物流体中的表面硬度、压痕模量、抗压强度以及尺寸稳定性。然而，脱水热处理样品的固态核磁共振或红外光谱未观察到差异，这表明机械性能和尺寸稳定性的提高是基于NFC和CMC界面处官能团的物理交联。如X射线衍射测量所揭示的，聚合物的超分子结构得到了很好的保留。交联支架显示出人类骨组织来源的成骨细胞（hFOB）的高增殖、活力和附着。本文提出的从市售材料设计纤维素基纤维状墨水和双孔支架的简单直接途径，无需任何额外的交联剂，应为用于骨组织再生和3D生物打印应用的可植入、可降解支架及载细胞生物材料的开发铺平道路。
