Megone William, Kong Dexu, Peng Lihui, Gautrot Julien E
Institute of Bioengineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK; School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
Institute of Bioengineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK; School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
J Colloid Interface Sci. 2021 Jul 15;594:650-657. doi: 10.1016/j.jcis.2021.03.055. Epub 2021 Mar 17.
The structuring of liquid-liquid and liquid-air interfaces may play an important role in novel microfabrication platforms and biotechnologies, from the spontaneous formation of microfilaments from liquid droplets and the 3D printing of liquids, to the culture of stem cells on emulsions. Understanding the mechanical anisotropy of associated liquid interfaces is essential for the development of such systems. Models of AFM indentation at liquid interfaces, based on the Young-Laplace model, currently do not allow the quantification of interfacial mechanical properties of associated molecular films. This report presents such a model and compares its predictions to interfacial mechanical properties characterised via interfacial shear rheology. An extreme reversal of mechanical anisotropy of liquid-liquid interfaces is observed, upon self-assembly of protein nanosheets, by 5 orders of magnitude. Results indicate that, although interfacial rheology is more sensitive than AFM indentation to the mechanics of molecular films in the low range of interfacial mechanics, AFM indentation allows the quantification of mechanical properties of stiffer molecular films, and remains better adapted to the characterisation of small samples and enables the characterisation of local heterogeneity.
液-液界面和液-气界面的结构在新型微制造平台和生物技术中可能起着重要作用，从液滴自发形成微丝、液体的3D打印到在乳液上培养干细胞。理解相关液体界面的机械各向异性对于此类系统的开发至关重要。基于杨氏-拉普拉斯模型的液体界面原子力显微镜压痕模型目前无法量化相关分子膜的界面力学性能。本报告提出了这样一个模型，并将其预测结果与通过界面剪切流变学表征的界面力学性能进行了比较。通过蛋白质纳米片的自组装，观察到液-液界面的机械各向异性发生了5个数量级的极端反转。结果表明，虽然在低界面力学范围内，界面流变学比原子力显微镜压痕对分子膜力学更敏感，但原子力显微镜压痕能够量化较硬分子膜的力学性能，并且仍然更适合于小样品的表征，并能够表征局部异质性。
