title: Surface elasticity and charge concentration-dependent endothelial cell attachment to copolymer polyelectrolyte hydrogel.
abstract: The surface micromechanical properties of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloxyethyl trimethyl ammonium chloride (MAETAC) copolymer hydrogels are probed using atomic force microscopy. HEMA-MAETAC polyelectrolyte hydrogels with increasing positive charge concentrations ranging from 0 to 400mM in increments of 40mM, are fabricated using different proportions of HEMA and MAETAC monomers. Increasing proportions of positively charged MAETAC monomers produce hydrogels with increasingly swollen states and correspondingly decreasing measures of stiffness, or Young's modulus. Increasing the relative proportion of charged monomers also increases the hysteresis in the approaching and retracting components of the force spectroscopy curves. When these hydrogels are equilibrated in cell-culture media without fetal bovine serum and a pH-controlled CO(2) environment, precipitation reactions increase the variability of the Young's modulus estimates. Adding a buffer, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, maintains physiological pH without the use of a CO(2) environment, and thus reduces salt precipitation reactions and the variability of the Young's modulus. The attachment of porcine pulmonary artery endothelial cells increases with increasing prepared hydrogel charge concentration and decreasing elasticity.
authors.affiliation: The University of Tennessee, Department of Mechanical, Aerospace and Biomedical Engineering, Knoxville, TN 37996, USA.
authors.forename: Seonghwan
authors.initials: S
authors.lastname: Kim
authors.forename: Anthony E
authors.initials: AE
authors.lastname: English
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Kihm
mesh_terms: D000643:Ammonium Chloride / Q000737:chemistry; D000818:Animals; D002245:Carbon Dioxide / Q000737:chemistry; D018929:Cell Culture Techniques / Q000295:instrumentation; D003470:Culture Media; D004548:Elasticity; D042783:Endothelial Cells / Q000166:cytology*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry*; D011651:Pulmonary Artery / Q000166:cytology; D013499:Surface Properties; D013552:Swine
chemical_list: C120889:2-(trimethylammonio)ethyl methacrylate; D003470:Culture Media; D008689:Methacrylates; D011108:Polymers; D000643:Ammonium Chloride; D002245:Carbon Dioxide; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C005044:hydroxyethyl methacrylate