Tabil Xavier L, Cao Tate N, Chen Xiongbiao
Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Ron & Jane Graham School of Professional Development, College of Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Biopolymers. 2025 Nov;116(6):e70050. doi: 10.1002/bip.70050.
Composites of sodium alginate (Alg) and carboxymethyl chitosan (CMCS) are used to 3D print tissue scaffolds, but the rheological properties and printability of these composites remain underreported, resulting in time-consuming trial-and-error printing. This study investigates these properties to rigorously design the 3D printing process. Dynamic shear tests characterize viscoelastic and frequency-dependent properties, while steady shear tests assess the apparent viscosity and temperature-dependent viscosity. A novel approach based on mass flow rate models guides the printing of two-layer scaffolds for printability analysis. Brightfield microscopy and printability indexes quantify the deviations between printed and designed scaffolds, defined as printability. Results show that Alg predominantly directs the rheological properties. At 4% w/v Alg, the addition of < 3% w/v CMCS reduces elasticity, contrary to the trend where increasing CMCS increases elasticity. CMCS improves the thermal resistance of the composites, while Alg reduces it. Of the composites printed, a 4% w/v Alg + 1% w/v CMCS formulation most accurately replicates the designed scaffold, and adding CMCS improves scaffold printing repeatability by at least threefold compared to Alg-only solutions. These findings provide a framework that informs the preparation and performance of Alg-CMCS composites with tunable properties, advancing scaffold bioprinting for tissue engineering.
海藻酸钠（Alg）和羧甲基壳聚糖（CMCS）的复合材料用于3D打印组织支架，但这些复合材料的流变学特性和可打印性仍鲜有报道，导致打印过程耗时且需反复试验。本研究对这些特性进行了探究，以严谨地设计3D打印工艺。动态剪切试验表征粘弹性和频率依赖性特性，而稳态剪切试验评估表观粘度和温度依赖性粘度。一种基于质量流率模型的新方法指导两层支架的打印以进行可打印性分析。明场显微镜和可打印性指数量化了打印支架与设计支架之间的偏差，定义为可打印性。结果表明，Alg主要决定流变学特性。在Alg浓度为4%（w/v）时，添加<3%（w/v）的CMCS会降低弹性，这与CMCS增加会提高弹性的趋势相反。CMCS提高了复合材料的耐热性，而Alg则降低了耐热性。在打印的复合材料中，4%（w/v）Alg + 1%（w/v）CMCS配方最准确地复制了设计的支架，并且与仅使用Alg的溶液相比，添加CMCS将支架打印的重复性提高了至少三倍。这些发现提供了一个框架，为具有可调特性的Alg-CMCS复合材料的制备和性能提供了依据，推动了用于组织工程的支架生物打印技术的发展。
