title: Accelerated cell sheet detachment by copolymerizing hydrophilic PEG side chains into PNIPAm nanocomposite hydrogels.
abstract: One-end-connected short poly(ethylene glycol) (PEG) side chains were facilely introduced into the poly(N-isopropylacrylamide) (PNIPAm) nanocomposite hydrogel (NC gel) via in situ copolymerization of NIPAm monomer and PEG macromonomer in the aqueous suspension of hectorite clay Laponite XLS. The NC gels were characterized with Fourier transform infrared and x-ray photoelectron spectroscopy for the composition, DSC and transmittance for the phase separation temperature, dynamic mechanical spectra and swelling ratio for the interaction. Increasing the PEG content led to a small increase in the storage modulus and the lower critical solution temperature (LCST) of the copolymerized NC gels, and the LCST of the copolymerized NC gels was still below 37 °C. The L929 cell adhesion and proliferation on the surface of these NC gels were not suppressed by the incorporation of hydrophilic PEG side chains. By lowering temperature below the LCST, the cell sheet spontaneously detached from the copolymerized NC gels. The surface morphology and surface wettability of the NC gels were detected by atom force microscope and contact angle measurement. A rough and hydrophilic surface induced by a small amount of PEG side chains was found to be favorable to accelerate the cell sheet detachment, probably due to the enhanced water permeation into the gel-cell sheet interface.
authors.affiliation: Research Institute of Materials Science and State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Xinxing
authors.initials: X
authors.lastname: Liu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tong
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D002152:Calorimetry, Differential Scanning; D002448:Cell Adhesion; D018929:Cell Culture Techniques; D002460:Cell Line; D055119:Elastic Modulus; D020100:Hydrogels; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D051379:Mice; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D011092:Polyethylene Glycols / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D020100:Hydrogels; D017640:Silicates; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols; C524813:laponite