Graft polymer thickness dependency on the resulting cell adhesion character. (a) Correlation between the percentage of adhered cell and thickness of the grafted PIPAAm gel layer. Blue circles and red squares represent PIPAAm-GC and PIPAAm-TCPS with various PIPAAm graft gel thickness, respectively. Reprinted permission from reference [28
]. Copyright © 2010,WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. (b) Illustration of graft polymer thickness dependency of PIPAAm-TCPS. PIPAAm-TCPS with 2.9 μ
(left) and 1.4 μ
(right) of PIPAAm graft density (right). At the interface of basal hydrophobic TCPS surface, grafted PIPAAm chains are dynamically restricted, highly aggregated, and dehydrated due to the TCPS surface. Such aggregation and dehydration successively dehydrated PIPAAm chains at the outermost surfaces, which allow the surfaces to be cell adhesive at 37°C (right). In the case of the surfaces thicker than 20 nm, the aggregation and dehydration do not effectively dehydrate PIPAAm layer in the outermost surfaces region (left). The outermost surface is more hydrated than thinner PIPAAm-TCPS. Resulting temperature-responsive cell culture surface shows a cell repellent character. Reprinted with permission from reference [27
]. Copyright © 2018, The Society of Polymer Science, Japan.