Full Length ArticleThermo-responsive polymer brushes on glass plate prepared from a new class of amino acid-derived vinyl monomers and their applications in cell-sheet engineering

- Amino acid-based polymer brushes were prepared on glass plate by SI-ATRP.
- Brushes showed phase transitions from swollen to collapsed states.
- Transition temperature (TT) could be varied by adjusting the copolymer composition.
- Brushes above TT behaved as effective support for cell adhesion without toxicity.
- Resultant cell-sheets were detached by cooling below the corresponding TTs.

In this study, we present a novel thermo-responsive polymer platform that is based on the alanine methyl ester-containing homopolymer (PNAAMe) and the copolymer with glycine methyl ester-based vinyl monomer (P(NAAMe-co-NAGMe)) brushes prepared via surface-initiated atom transfer radical polymerization. Water contact angles for these brushes measured at different temperatures reveal that the polymer brushes collapse and dehydrate around 13 °C and 25 °C (TTs), respectively, upon elevating the temperature. At 37 °C, seeded fibroblasts (NIH/3T3) adhere to and spread well onto these brush surfaces although the copolymer brush of P(NAAMe-co-NAGMe) depresses the number of adherent cells less than half of that for the homopolymer of PNAAMe after 24 h of cell culture due to increment in hydrophilicity. To prepare the cell-sheet, the cells are seeded on both polymer brushes and cultured at 37 °C in the presence of serum. After 4 days, the cells proliferated confluently on these brush surfaces. Lowering the temperature to 4 °C and 20 °C below TT of each brush led to the cell-sheet detachment as a monolayer form from the polymer brushes accompanying with the switching of surface affinity.

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