Abstract Collagen and chitosan are widely employed as biomaterials, including for 3D-bioprinting. However, the use of collagen and chitosan (col:chi) blends as bioinks is still scarce. In this work, the rheology of different hydrogel precursors (0.5–1.50% w/v chi: 0.18–0.54% w/v col) was analyzed through frequency and strain sweeps, as well as at different shear rates. Col:chi blends showed a shear-thinning behavior, with viscosity values at low shear rates between 0.35 and 2.80 Pa s. Considering the strain rate determined by the applied flow in a 3D-bioprinter, precursor viscosities during the extrusion were in the interval 0.5–0.8 Pa s. Printability (Pr) was measured comparing images of the printed meshes and the corresponding CAD grid design, using photograph analysis. Col:chi 0.36:1.00 was chosen to print mono-layered scaffolds for tissue engineering (TE) because of its suitable viscosity, printability and polymer ratio content. Hydrogels were obtained through NaHCO3 nebulization and 37° incubation, and NHS/EDC were added to obtain scaffolds with improved mechanical behavior. They were stable after 44 h in PBS with collagenase at physiological level and showed no cytotoxic effect in NIH-3T3 fibroblasts.

中文翻译：

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用于 3D 生物打印的胶原蛋白和壳聚糖混合物：一种流变学和可印刷性方法

摘要 胶原蛋白和壳聚糖被广泛用作生物材料，包括用于 3D 生物打印。然而，使用胶原蛋白和壳聚糖 (col:chi) 混合物作为生物墨水的情况仍然很少。在这项工作中，通过频率和应变扫描以及不同的剪切速率分析了不同水凝胶前体（0.5–1.50% w/v chi: 0.18–0.54% w/v col）的流变学。Col:chi 混合物表现出剪切稀化行为，在 0.35 和 2.80 Pa s 之间的低剪切速率下粘度值。考虑到由 3D 生物打印机中的应用流确定的应变率，挤出过程中的前体粘度在 0.5-0.8 Pa s 的区间内。使用照片分析，通过比较打印网格和相应 CAD 网格设计的图像来测量适印性 (Pr)。Col:chi 0.36:1。选择 00 打印用于组织工程 (TE) 的单层支架，因为它具有合适的粘度、可印刷性和聚合物比例含量。通过 NaHCO3 雾化和 37°孵育获得水凝胶，并添加 NHS/EDC 以获得具有改进机械性能的支架。它们在生理水平的胶原酶的 PBS 中 44 小时后稳定，并且在 NIH-3T3 成纤维细胞中没有显示细胞毒性作用。