Lallemang Max, Yu Leixiao, Cai Wanhao, Rischka Klaus, Hartwig Andreas, Haag Rainer, Hugel Thorsten, Balzer Bizan N
Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany.
Cluster of Excellence livMatS @ FIT-Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany.
Nanoscale. 2022 Mar 10;14(10):3768-3776. doi: 10.1039/d1nr08338d.
Multivalent interactions play a leading role in biological processes such as the inhibition of inflammation or virus internalization. The multivalent interactions show enhanced strength and better selectivity compared to monovalent interactions, but they are much less understood due to their complexity. Here, we detect molecular interactions in the range of a few piconewtons to several nanonewtons and correlate them with the formation and subsequent breaking of one or several bonds and assign these bonds. This becomes possible by performing atomic force microcopy (AFM)-based single molecule force spectroscopy of a multifunctional polymer covalently attached to an AFM cantilever tip on a substrate bound polymer layer of the multifunctional polymer. Varying the pH value and the crosslinking state of the polymer layer, we find that bonds of intermediate strength (non-covalent), like coordination bonds, give the highest multivalent bond strength, even outperforming strong (covalent) bonds. At the same time, covalent bonds enhance the polymer layer density, increasing in particular the number of non-covalent bonds. In summary, we can show that the key for the design of stable and durable polymer coatings is to provide a variety of multivalent interactions and to keep the number of non-covalent interactions at a high level.
多价相互作用在诸如炎症抑制或病毒内化等生物过程中起主导作用。与单价相互作用相比，多价相互作用表现出更强的强度和更好的选择性，但由于其复杂性，人们对它们的了解要少得多。在这里，我们检测了几皮牛顿到几纳牛顿范围内的分子相互作用，并将它们与一个或几个键的形成及随后的断裂相关联，并对这些键进行了赋值。通过对共价连接到原子力显微镜（AFM）悬臂尖端的多功能聚合物在基底上的多功能聚合物层进行基于原子力显微镜的单分子力谱分析，这成为可能。通过改变聚合物层的pH值和交联状态，我们发现中等强度（非共价）的键，如配位键，给出了最高的多价键强度，甚至超过了强（共价）键。同时，共价键提高了聚合物层的密度，特别是增加了非共价键的数量。总之，我们可以表明，设计稳定耐用的聚合物涂层的关键是提供多种多价相互作用，并使非共价相互作用的数量保持在较高水平。
