title: Thermoresponsive comb-shaped copolymer-Si(100) hybrids for accelerated temperature-dependent cell detachment.
abstract: Well-defined comb-shaped copolymer-Si(100) hybrids were prepared, via successive surface-initiated atom transfer radical polymerizations (ATRPs) of glycidyl methacrylate (GMA) and N-isopropylacrylamide (NIPAAm), for accelerated cell detachment at a lower temperature. The Si-C bonded comb copolymer consisted of a well-defined (nearly monodispersed) poly(glycidyl methacrylate) (P(GMA)) main chain, a well-defined NIPAAm polymer (P(NIPAAm) block, and well-defined P(NIPAAm) side chains. The ring opening reaction of epoxy groups of the P(GMA) main chain with 2-chloropropionic acid resulted in the immobilization of the alpha-chloroester groups (the ATRP initiators for the NIPAAm side chains) and the concomitant formation of hydroxyl groups. P(NIPAAm) acted as the thermoresponsive side chains of the comb copolymer for control of cell adhesion and detachment, while the P(GMA) main chain with hydroxyl groups provided a local hydrophilic microenvironment. The unique microstructure of the comb copolymer brushes facilitated cell recovery at 20 degrees C (below the lower critical solution temperature (LCST) of P(NIPAAm)) without restraining cell attachments and growth at 37 degrees C. The accelerated detachment of cells indicated that the underlying hydrophilic environment of the comb copolymer brushes contributed to speedy hydration of the P(NIPAAm) segments below the LCST. The thermoresponsive comb copolymer-Si(100) hybrids are potentially useful as adhesion modifiers for cells in silicon-based biomedical devices.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260, Singapore.
authors.forename: F J
authors.initials: FJ
authors.lastname: Xu
authors.forename: S P
authors.initials: SP
authors.lastname: Zhong
authors.forename: L Y L
authors.initials: LY
authors.lastname: Yung
authors.forename: Y W
authors.initials: YW
authors.lastname: Tong
authors.forename: En-Tang
authors.initials: ET
authors.lastname: Kang
authors.forename: K G
authors.initials: KG
authors.lastname: Neoh
mesh_terms: D016475:3T3 Cells; D000180:Acrylic Resins; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D007700:Kinetics; D051379:Mice; D011109:Polymethacrylic Acids; D012825:Silicon; D013696:Temperature; D013816:Thermodynamics
chemical_list: D000180:Acrylic Resins; D011109:Polymethacrylic Acids; C042535:polyglycidyl methacrylate; C052970:poly-N-isopropylacrylamide; D012825:Silicon