Institute of Physical Chemistry and Electrochemistry, Leibniz Universität Hannover, Callinstr. 3A, 30167 Hannover, Germany.
Acta Biomater. 2021 Dec;136:243-253. doi: 10.1016/j.actbio.2021.09.012. Epub 2021 Sep 13.
Thermally "switchable" poly(glycidyl ether) (PGE) brushes constitute effective coatings for the temperature-triggered harvest of confluent cell sheets. Based on a simple "grafting-to" approach, such coatings can be tethered to various applied plastic culture substrate materials. Herein, we elucidate the self-assembly of PGE brushes with tunable grafting densities up to 0.12 and 0.22 chains nm on polystyrene (PS) and tissue culture PS (TCPS), respectively. In terms of temperature-dependent wettability and protein adsorption, we found that brushes exhibit distinct grafting density-dependent properties which correlate with their cell sheet fabrication performance. In addition, temperature-ramped quartz-crystal microbalance with dissipation (QCM-D) measurements revealed marked substrate-specific PGE phase transitions which allowed us to deduce comprehensive switching mechanisms. Thus, we demonstrate that brushes tethered to hydrophilic TCPS (contact angle (CA) ∼ 60°) undergo a "cushioned" transition comprising a non-switchable, hydrated basal layer as well as a switchable top layer which regulates cell sheet detachment. In contrast, PGE brushes tethered to PS undergo a "grounded" transition which is substantially influenced by the dehydrating effect of the less hydrophilic PS substrate (CA ∼ 90°). These divergent phase transition mechanisms give rise to a broad scope in cell sheet fabrication performance, yielding staggered detachment times within a 30 min to 3 h range. Hence, we emphasize the importance of a detailed knowledge on the effect of applied culture substrates on the thermal switchability and phase transition characteristics of thermoresponsive brush coatings to accomplish an optimized design for functional cell culture dishes. STATEMENT OF SIGNIFICANCE: As the first comparative study of its kind, we elucidate the substrate-dependent thermal switchability of thermoresponsive brush coatings and evaluate their grafting density-dependent phase transition mechanism and its effect on cell sheet fabrication performance.
基于简单的“接枝到”方法，热“可切换”聚（缩水甘油醚）（PGE）刷可用于将各种应用的塑料培养基底材料固定到温度触发的细胞片收获中。在此，我们阐明了 PGE 刷的自组装，其接枝密度高达 0.12 和 0.22 链 nm 分别在聚苯乙烯（PS）和组织培养 PS（TCPS）上。就温度依赖性润湿性和蛋白质吸附而言，我们发现刷子表现出明显的接枝密度依赖性性质，这与它们的细胞片制造性能相关。此外，温度斜坡石英晶体微天平与耗散（QCM-D）测量显示出明显的基底特异性 PGE 相变，使我们能够推断出全面的开关机制。因此，我们证明了与亲水性 TCPS（接触角（CA）≈60°）接枝的刷子经历了一个“缓冲”转变，该转变包含一个不可切换的、水合的底层以及一个可切换的顶层，该顶层调节细胞片的脱落。相比之下，与 PS 接枝的 PGE 刷子经历了一个“接地”转变，该转变受到疏水性 PS 基底脱水效应的极大影响（CA≈90°）。这些发散的相变机制为细胞片制造性能提供了广泛的范围，在 30 分钟至 3 小时的范围内产生了交错的脱落时间。因此，我们强调了详细了解应用培养底物对热响应性刷涂层热可切换性和相变特性的影响的重要性，以实现功能细胞培养皿的优化设计。
