Mechanical rheometry, specifically rotational rheometry, squeeze flow, and capillary rheometry, and two microrheology methods, namely multiple-particle tracking (MPT) and diffusing wave spectroscopy (DWS) have been used to get new insight into structural and dynamical properties of alginate dissolved in solvents widely used for bioprinting, namely deionized water, phosphate-buffered saline (PBS), and Dulbecco Modified Eagle Medium (DMEM) cell media. Results demonstrate that alginate rheological properties depend on the solvent quality at concentrations higher than 1 wt.%. In this high concentration regime, in aqueous salt-free and PBS solutions, experimental scaling exponents for the concentration dependence of the specific viscosity η sp and the plateau modulus G 0 agree well with theoretical predictions for neutral polymers in good solvent whereas for the terminal relaxation time T R , the exponent is slightly higher than theoretically predicted, presumably due to the formation of aggregates. For alginate dissolved in DMEM, all exponents for η sp , G 0 , and T R agree with predictions for polymers in theta solvents, which might be related to the formation of polyelectrolyte complex as a result of interactions between alginate and amino acids. Chain persistence length l p values, as determined directly from high frequency rheometry for the first time, are independent of alginate concentration and temperature. Lower absolute l p values were found for DMEM solutions compared with the other solvents. Moreover, scaling exponents for η sp , G 0 , and T R do not change with temperature, within 20 and 60 °C. These findings suggest no change in the conformation of alginate chains with temperature. Graphical abstract Alginate rheological properties depend on the solvent quality

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不同溶剂中藻酸盐溶液的链灵活性和动力学

机械流变学，特别是旋转流变学、挤压流和毛细管流变学，以及两种微流变学方法，即多粒子跟踪 (MPT) 和扩散波谱 (DWS) 已被用于对溶解在水中的藻酸盐的结构和动力学特性有新的了解。广泛用于生物打印的溶剂，即去离子水、磷酸盐缓冲盐水 (PBS) 和 Dulbecco 改良 Eagle 培养基 (DMEM) 细胞培养基。结果表明，藻酸盐的流变特性取决于浓度高于 1 wt.% 时的溶剂质量。在这种高浓度方案中，在无盐水溶液和 PBS 溶液中，比粘度 η sp 和平台模量 G 0 的浓度依赖性的实验标度指数与良好溶剂中中性聚合物的理论预测非常吻合，而对于末端弛豫时间 TR ，指数略高于理论预测，大概是由于聚集体的形成。对于溶解在 DMEM 中的藻酸盐，η sp 、G 0 和 TR 的所有指数都与在 theta 溶剂中的聚合物的预测一致，这可能与藻酸盐和氨基酸之间相互作用导致聚电解质复合物的形成有关。链持久长度 lp 值首次直接从高频流变测定法确定，与藻酸盐浓度和温度无关。与其他溶剂相比，DMEM 溶液的绝对 lp 值较低。此外，η sp 、G 0 和 TR 的标度指数在 20 和 60 °C 内不随温度变化。这些发现表明藻酸盐链的构象没有随温度变化。图形摘要 海藻酸盐的流变特性取决于溶剂质量