Thermo-responsive PNiPAAm-g-PEG films for controlled cell detachment.
A series of graft copolymers consisting of either poly(N-isopropylacrylamide) (PNiPAAm) or poly(N,N-diethylacrylamide) (PDEAAm) as a thermo-responsive component in the polymer backbone and poly(ethyleneglycol) (PEG) were immobilized as thin films and cross-linked on a fluoropolymer substrate using low-pressure argon plasma treatment. The surface-immobilized hydrogels exhibit a transition from partially collapsed to completely swollen, which is in the range of 32-35 degrees C and corresponds to the lower critical solution temperature of the soluble polymers. The hydrogels were used as cell carriers in culture experiments with L929 mouse fibroblast cells to probe for cell adhesion, proliferation, and temperature-dependent detachment of cell layers. The fibroblast cells adhere, spread, and proliferate on the hydrogel layers at 37 degrees C and become completely detached after reducing the temperature by 3 K. The cell release characteristics were further correlated to the swelling and collapsing behavior of the hydrogel films and the polymer solutions as measured in PBS solution and RPMI cell cultivation medium. It could be shown that, long before the swelling has completed upon temperature reduction, the cells detach. This can be attributed to the large content of PEG present in the hydrogel, which weaken the cell adhesion strength to the hydrogel layers.
Schmaljohann
Dirk
D
Institute of Polymer Research Dresden & Max Bergmann Center of Biomaterials Dresden, Hohe Str. 6, 01069 Dresden, Germany. schmaljohann@ipfdd.de
Oswald
Joachim
J
Jørgensen
Birgitte
B
Nitschke
Mirko
M
Beyerlein
Detlev
D
Werner
Carsten
C
D000180:Acrylic Resins / Q000494:pharmacology; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D018929:Cell Culture Techniques / Q000379:methods*; D002460:Cell Line; D005347:Fibroblasts / Q000166:cytology*; D020100:Hydrogels / Q000737:chemistry* / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D011092:Polyethylene Glycols / Q000494:pharmacology; D013696:Temperature
D000180:Acrylic Resins; D020100:Hydrogels; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols