title: Thermally responsive polymeric hydrogel brushes: synthesis, physical properties and use for the culture of chondrocytes.
abstract: Hydrogel brushes are materials composed of a water-swollen network, which contains polymer chains that are grafted with another polymer. Using a thermally responsive polymer, poly(N-isopropyl acrylamide) (polyNIPAM), as the graft component we are able to maintain the critical solution temperature (Tcrit), independent of the overall composition of the material, at approximately 32 degrees C. The change in swelling at Tcrit is a function of the amount of polyNIPAM in the system. However, there is a much smaller change in the surface contact angles at Tcrit. PolyNIPAM-based materials have generated considerable interest, as 'smart' substrates for the culture of cells and here, we show the utility of hydrogel brushes in cell culture. Chondrocytes attached to the hydrogel brushes and yielded viable cell cultures. Moreover, the chondrocytes could be released from the hydrogel brushes without the use of proteases by reducing the temperature of the cultures to below Tcrit to induce a change in the conformation of the polyNIPAM chain at Tcrit. The importance of the crosslink hydrogel component is illustrated by significant changes in cell attachment/cell viability as the crosslink density is changed.
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield, South Yorkshire S3 7HF, UK.
authors.forename: John
authors.initials: J
authors.lastname: Collett
authors.forename: Aileen
authors.initials: A
authors.lastname: Crawford
authors.forename: Paul V
authors.initials: PV
authors.lastname: Hatton
authors.forename: Mark
authors.initials: M
authors.lastname: Geoghegan
authors.forename: Stephen
authors.initials: S
authors.lastname: Rimmer
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods*; D022081:Cell Surface Extensions; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology*; D004548:Elasticity; D006244:Hardness; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D020100:Hydrogels; C052970:poly-N-isopropylacrylamide