There is significant interest in developing new approaches for culturing mammalian cells in a three‐dimensional (3D) environment due to the fact that it better recapitulates the in vivo environment. The goal of this work was to develop thiol‐acrylate, biodegradable hydrogels that possess highly tunable properties to support in vitro 3D culture. Six different hydrogel formulations were synthesized using two readily available monomers, a trithiol (ETTMP 1300 [ethoxylated trimethylolpropane tri(3‐mercaptopropionate) 1300]) and a diacrylate (PEGDA 700 [polyethylene glycol diacrylate 700]), polymerized by a base‐catalyzed Michael addition reaction. The resultant hydrogels were homogeneous, hydrophilic, and biodegradable. Different mechanical properties such as gelation time, storage modulus (or the elasticity G'), swelling ratio, and rate of degradation were tuned by varying the weight percentage of polymer, the molar ratio of thiol‐to‐acrylate groups, and the pH of the solution. Cytocompatibility was assessed using two model breast cancer cell lines by both 2D and 3D cell culturing approaches. The hydrogel formulations with a thiol‐to‐acrylate molar ratio of 1.05 were found to be optimal for both 2D and 3D cultures with MDA‐MB‐231 cellular aggregates found to be viable after 17 days of 3D continuous culture. Finally, MCF7 cells were observed to form 3D spheroids up to 600 μm in diameter as proof of principle for the thiol‐acrylate hydrogel to function as a scaffold for in vitro 3D cell culture. A comparison of the different mechanical properties of the six hydrogel formulations coupled with in vitro cell culture results and findings from previously published hydrogels conclude that the thiol‐acrylate hydrogels have significant potential as a scaffold for 3D cell culture.

中文翻译：

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使用碱催化迈克尔加成法合成和表征硫醇丙烯酸酯水凝胶，用于 3D 细胞培养应用。

开发在三维 (3D) 环境中培养哺乳动物细胞的新方法引起了人们极大的兴趣，因为它可以更好地概括体内环境。这项工作的目标是开发具有高度可调特性的硫醇丙烯酸酯、可生物降解的水凝胶，以支持体外 3D 培养。使用两种容易获得的单体合成了六种不同的水凝胶配方，三硫醇（ETTMP 1300 [乙氧基化三羟甲基丙烷三（3-巯基丙酸酯）1300]）和二丙烯酸酯（PEGDA 700 [聚乙二醇二丙烯酸酯 700]），由碱催化迈克尔加成反应。所得水凝胶均匀、亲水且可生物降解。不同的机械性能，如凝胶时间、储能模量（或弹性G')、溶胀比和降解速率通过改变聚合物的重量百分比、硫醇与丙烯酸酯基团的摩尔比和溶液的 pH 值来调节。通过 2D 和 3D 细胞培养方法，使用两种模型乳腺癌细胞系评估细胞相容性。发现硫醇与丙烯酸酯摩尔比为 1.05 的水凝胶配方最适合 2D 和 3D 培养，其中 MDA-MB-231 细胞聚集体在 3D 连续培养 17 天后仍可存活。最后，观察到 MCF7 细胞形成直径高达 600 μm 的 3D 球体，作为硫醇丙烯酸酯水凝胶作为体外 3D 细胞培养支架的原理证明。