AbstractDynamic polymer materials are highly valued substrates for 3D cell culture due to their viscoelasticity, a time‐dependent mechanical property that can be tuned to resemble the energy dissipation of native tissues. Herein, we report the coupling of a cyclic thiosulfinate, mono‐S‐oxo‐4‐methyl asparagusic acid, to a 4‐arm PEG‐OH to prepare a disulfide‐based dynamic covalent hydrogel with the addition of 4‐arm PEG‐thiol. Ring opening of the cyclic thiosulfinate by nucleophilic substitution results in the rapid formation of a network showing a viscoelastic fluid‐like behaviour and relaxation rates modulated by thiol content through thiol‐disulfide exchange, whereas its viscoelastic behaviour upon application as a small molecule linear crosslinker is solid‐like. Further introduction of 4‐arm PEG‐vinylsulfone in the network yields a hydrogel with weeks‐long cell culture stability, permitting 3D culture of cell types that lack robust proliferation, such as human pluripotent stem cell‐derived cardiomyocytes (hPSC‐CMs). These cells display native behaviours such as cell elongation and spontaneous beating as a function of the hydrogel's mechanical properties. We demonstrate that the mode of dynamic cyclic thiosulfinate crosslinker presentation within the network can result in different stress relaxation profiles, opening the door to model tissues with disparate mechanics in 3D cell culture.
摘要 动态聚合物材料因其粘弹性而成为三维细胞培养的重要基质,粘弹性是一种随时间变化的机械特性,可通过调节使其类似于原生组织的能量耗散。在此,我们报告了环状硫代硫酸酯(单-S-氧代-4-甲基天冬酰胺酸)与 4 臂 PEG-OH 的偶联,从而制备出一种基于二硫化物的动态共价水凝胶,并添加了 4 臂 PEG-硫醇。环状硫代硫酸酯通过亲核取代迅速形成网络,表现出类似粘弹性流体的行为,其弛豫速率通过硫醇-二硫化物交换受硫醇含量的调节,而在用作小分子线性交联剂时,其粘弹性行为则表现为类似固体的行为。在网络中进一步引入 4-臂 PEG-乙烯基砜后,水凝胶具有长达数周的细胞培养稳定性,可用于缺乏增殖能力的细胞类型的三维培养,如人类多能干细胞衍生的心肌细胞(hPSC-CMs)。这些细胞在水凝胶机械特性的作用下表现出细胞伸长和自发跳动等原生行为。我们证明,网络内动态环状硫代亚硫酸盐交联剂的呈现模式可导致不同的应力松弛曲线,从而为在三维细胞培养中建立具有不同力学特性的组织模型打开了大门。