Functional Polymers and Colloids

合成聚两性聚合物是由阴离子、阳离子和中性单体形成的共聚物，具有令人着迷的溶液性质，类似于一类重要的蛋白质，称为固有无序蛋白质。我们将制备一系列以丙烯酸类单体为基础的非化学计量比的聚两性聚合物，这些单体具有一定的阳离子与阴离子比例，并通过加入中性共聚单体来控制不同的电荷密度。我们将探索这些共聚物作为粘性液体凝聚体从水溶液中相分离的能力，以响应盐度、pH、温度和其他聚合物的存在的微妙且通常是协同的变化。这些两性聚体及其凝聚体具有高度的细胞相容性，我们将探索它们作为合成细胞外基质的成分的用途，特别是它们满足许多哺乳动物细胞附着需求的能力。我们以前已经证明，这种聚两性离子具有作为细胞冷冻保护剂的巨大潜力。与此同时，我们正在开发高度水合的聚合物微凝胶，轻度交联，光学透明，膨胀时直径为5至20微米的球形聚合物凝胶。这些实体是在边缘溶剂中通过沉淀聚合形成的，这是我们最初开发的一种独特工艺，可以产生放射状结构的、不含表面活性剂的微凝胶。我们现在计划探索将这些微凝胶用作细胞外基质的颗粒成分，特别是用于测试不同类型细胞在组织中的迁移，包括转移癌细胞、胚胎细胞和免疫监视细胞。这将涉及微凝胶与上述两性聚合物的接枝，以允许更好地控制细胞粘附性以及这些合成的3D组织仿制品的粘弹性特性。其他应用可能包括使用类似的带有液体凝聚核的改性微凝胶作为模板，使用单一吸收的酶以及细胞提取物来进行无细胞生物学。这项工作将涉及在某些细胞类型方面具有专业知识的合作者，并可能导致更好地了解细胞行为的有用方法。

Synthetic polyampholytes, copolymers formed from anionic, cationic and neutral monomers, have fascinating solution properties that resemble those of an important class of proteins called Inherently Disordered Proteins. We will prepare series of non-stoichiometric polyampholytes based on acrylic monomers with a range of cation to anion ratios, and with different charge densities controlled by incorporation of neutral comonomers. We will explore the ability of these copolymers to phase separate as viscous liquid coacervates from aqueous solution, in response to subtle and often cooperative changes in salinity, pH, temperature, and presence of other polymers. These polyampholytes and their coacervates are highly cell compatible, and we will explore their use as components of synthetic extracellular matrices, with particular focus on their ability to fulfill the attachment needs of many mammalian cells. We have previously shown that such polyampholytes have significant potential as cell cryoprotectants. At the same time, we are developing highly hydrated polymer microgels, lightly crosslinked, optically transparent, spherical polymer gels of 5 to 20 micrometer diameter when swollen. These entities are formed by precipitation polymerization in marginal solvents, a unique process we originally developed, that results in radially structured, surfactant-free microgels. We now plan to explore the use of these microgels as granular components of extracellular matrices, in particular for assays to test migration of different cell types through tissue, including metastatic cancer cell, embryonic cells, and immune surveillance cells. This will involve microgels grafted with the above polyampholytes to allow better control over cell adhesion as well as visco-elastic properties of these synthetic 3D tissue mimics. Additional applications may involve using similar modified microgels with liquid coacervate cores as templates for cell-free biology using single absorbed enzymes as well as cell extracts. This work will involve collaborators with expertise in certain cell types, and could lead to useful approaches to better understand cell behaviour.