Synthetically modified proteins, such as gelatin methacryloyl (GelMA), are growing in popularity for bioprinting and biofabrication. GelMA is a photocurable macromer that can rapidly form hydrogels, while also presenting bioactive peptide sequences for cellular adhesion and proliferation. The mechanical properties of GelMA are highly tunable by modifying the degree of substitution via synthesis conditions, though the effects of source material and thermal gelation have not been comprehensively characterized for lower concentration gels. Herein, the effects of animal source and processing sequence are investigated on scaffold mechanical properties. Hydrogels of 4–6 wt% are characterized. Depending on the temperature at crosslinking, the storage moduli for GelMA derived from pigs, cows, and cold‐water fish range from 723 to 7340 Pa, 516 to 3484 Pa, and 294 to 464 Pa, respectively. The maximum storage moduli are achieved only by coordinated physical gelation and chemical crosslinking. In this method, the classic thermo‐reversible gelation of gelatin occurs when GelMA is cooled below a thermal transition temperature, which is subsequently “locked in” by chemical crosslinking via photocuring. The effects of coordinated physical gelation and chemical crosslinking are demonstrated by precise photopatterning of cell‐laden microstructures, inducing different cellular behavior depending on the selected mechanical properties of GelMA.

中文翻译：

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明胶甲基丙烯酰 (GelMA) 水凝胶中协调物理凝胶化和化学交联的流变学性质。

合成修饰的蛋白质，例如明胶甲基丙烯酰 (GelMA)，在生物打印和生物制造中越来越受欢迎。GelMA 是一种可光固化的大分子单体，可以快速形成水凝胶，同时还提供用于细胞粘附和增殖的生物活性肽序列。GelMA 的机械性能可以通过合成条件改变取代度来高度调节，尽管对于较低浓度的凝胶，源材料和热凝胶的影响尚未得到全面表征。本文研究了动物来源和加工顺序对支架机械性能的影响。表征了 4-6 wt% 的水凝胶。根据交联温度，来自猪、牛和冷水鱼的 GelMA 的储存模量范围为 723 至 7340 Pa、516 至 3484 Pa，和 294 至 464 Pa，分别。只有通过协调的物理凝胶化和化学交联才能实现最大的储存模量。在这种方法中，当 GelMA 冷却至低于热转变温度时，明胶发生经典的热可逆凝胶化，随后通过光固化的化学交联“锁定”。通过对载有细胞的微结构进行精确的光图案化证明了协调物理凝胶化和化学交联的效果，根据所选择的 GelMA 机械性能诱导不同的细胞行为。随后通过光固化的化学交联“锁定”。通过对载有细胞的微结构进行精确的光图案化证明了协调物理凝胶化和化学交联的效果，根据所选择的 GelMA 机械性能诱导不同的细胞行为。随后通过光固化的化学交联“锁定”。通过对载有细胞的微结构进行精确的光图案化证明了协调物理凝胶化和化学交联的效果，根据所选择的 GelMA 机械性能诱导不同的细胞行为。