title: Thermoresponsive PEG-based polymer layers: surface characterization with AFM force measurements.
abstract: Thermoresponsive polymer-coated surfaces based on poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol) methacrylate) [P(MEO(2)MA-co-OEGMA)] allow switching between cell attachment and detachment. Here, we investigate the temperature-dependent surface interactions between the polymer coating and a colloidal probe in an aqueous medium by means of atomic force microscopy (AFM) force-distance measurements. The analysis of the adhesion forces from AFM retraction curves identifies two kinds of regimes for the copolymer at temperatures below and above the lower critical solution temperature (LCST). Whereas at 25 degrees C the surface interactions with the polymer in the swollen state are dominated by repulsive forces, at 37 degrees C the surface interactions switch to attractive forces and a stronger adhesion is detected by AFM. Running several heating/cooling cycles repeatedly shows that switching the surface properties provides reproducible adhesion force values. Time-dependent measurements give insight into the switching kinetics, demonstrating that the cell response is coupled to the polymer kinetics but probably limited by the cellular rearrangements.
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Interfaces Department, D-14476 Potsdam-Golm, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kessel
authors.forename: Stephan
authors.initials: S
authors.lastname: Schmidt
authors.forename: Renate
authors.initials: R
authors.lastname: Müller
authors.forename: Erik
authors.initials: E
authors.lastname: Wischerhoff
authors.forename: André
authors.initials: A
authors.lastname: Laschewsky
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lutz
authors.forename: Katja
authors.initials: K
authors.lastname: Uhlig
authors.forename: Andreas
authors.initials: A
authors.lastname: Lankenau
authors.forename: Claus
authors.initials: C
authors.lastname: Duschl
authors.forename: Andreas
authors.initials: A
authors.lastname: Fery
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D003102:Colloids; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D007700:Kinetics; D008689:Methacrylates / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D018625:Microscopy, Atomic Force; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D003102:Colloids; D016326:Extracellular Matrix Proteins; D008689:Methacrylates; C549286:poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol) methacrylate); D011092:Polyethylene Glycols; D006046:Gold