Kim Seonghwan, English Anthony E, Kihm Kenneth D
The University of Tennessee, Department of Mechanical, Aerospace and Biomedical Engineering, Knoxville, TN 37996, USA.
Acta Biomater. 2009 Jan;5(1):144-51. doi: 10.1016/j.actbio.2008.07.033. Epub 2008 Aug 14.
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.
使用原子力显微镜探测甲基丙烯酸2-羟乙酯（HEMA）和甲基丙烯酰氧乙基三甲基氯化铵（MAETAC）共聚物水凝胶的表面微机械性能。采用不同比例的HEMA和MAETAC单体，制备了正电荷浓度以40mM为增量从0增加到400mM的HEMA-MAETAC聚电解质水凝胶。带正电荷的MAETAC单体比例增加，会使水凝胶的溶胀状态增加，相应地刚度（即杨氏模量）测量值降低。带电单体相对比例的增加也会增加力谱曲线接近和回缩部分的滞后现象。当这些水凝胶在不含胎牛血清且pH值可控的CO₂环境的细胞培养基中平衡时，沉淀反应会增加杨氏模量估计值的变异性。添加缓冲剂4-(2-羟乙基)-1-哌嗪乙磺酸可在不使用CO₂环境的情况下维持生理pH值，从而减少盐沉淀反应以及杨氏模量的变异性。猪肺动脉内皮细胞的附着随着所制备水凝胶电荷浓度的增加和弹性的降低而增加。
