Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmoe, Sweden.
Department of Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
J Colloid Interface Sci. 2014 Aug 15;428:242-50. doi: 10.1016/j.jcis.2014.04.058. Epub 2014 May 4.
The adsorption and mechanical stability of bovine submaxillary mucins (BSM) films at solid-liquid interfaces were studied with respect to both substrate hydrophobicity and solution pH. Dynamic light scattering revealed a single peak distribution in neutral aqueous solution (pH 7.4) and a small fraction with enhanced aggregation was observed in acidic solution (pH 3.8). Both substrate hydrophobicity and solution pH were found to affect the spontaneous adsorption of BSM onto solid surfaces; BSM adsorbed more onto hydrophobic surfaces than hydrophilic ones, and adsorbed more at pH 3.8 than at pH 7.4. Thus, the highest "dry" adsorbed mass was observed for hydrophobic surfaces in pH 3.8 solution. However, a highest "wet" adsorbed mass, i.e. which includes the solvent coupled to the film, was observed for hydrophobic surfaces at pH 7.4. The mechanical stability of the films was studied at the nanoscale with an atomic force microscope operated in the friction force spectroscopy mode. Results revealed that BSM films formed on hydrophobic substrates were stronger than those formed on hydrophilic ones. Moreover, the film stability also depended on the ambient pH and stronger films were formed at acidic conditions, i.e. close to the BSM isoelectric point.
研究了牛颌下腺黏蛋白（BSM）在固液界面处的吸附和机械稳定性，考虑了基底疏水性和溶液 pH 值。动态光散射显示在中性水溶液（pH7.4）中存在单一的峰分布，在酸性溶液（pH3.8）中观察到一小部分增强的聚集。发现基底疏水性和溶液 pH 值都影响 BSM 在固体表面上的自发吸附；BSM 在疏水性表面上的吸附比亲水性表面上的吸附更多，在 pH3.8 时的吸附比在 pH7.4 时的吸附更多。因此，在 pH3.8 溶液中的疏水性表面上观察到最高的“干燥”吸附质量。然而，在 pH7.4 时，在疏水性表面上观察到最高的“湿”吸附质量，即包括与膜耦合的溶剂。使用原子力显微镜以摩擦力谱模式在纳米尺度上研究了膜的机械稳定性。结果表明，在疏水性基底上形成的 BSM 膜比在亲水性基底上形成的膜更强。此外，膜稳定性还取决于环境 pH 值，在酸性条件下形成的膜更稳定，即接近 BSM 的等电点。
