Thermoresponsive PEG-based polymer layers: surface characterization with AFM force measurements.
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.
Kessel
Stefanie
S
Max Planck Institute of Colloids and Interfaces, Interfaces Department, D-14476 Potsdam-Golm, Germany.
Schmidt
Stephan
S
Müller
Renate
R
Wischerhoff
Erik
E
Laschewsky
André
A
Lutz
Jean-François
JF
Uhlig
Katja
K
Lankenau
Andreas
A
Duschl
Claus
C
Fery
Andreas
A
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
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