In the study of multivalent interactions at interfaces, as occur for example at cell membranes, the density of the ligands or receptors displayed at the interface plays a pivotal role, affecting both the overall binding affinities and the valencies involved in the interactions. In order to control the ligand density at the interface, several approaches have been developed, and they concern the functionalization of a wide range of materials. Here, different methods employed in the modification of surfaces with controlled densities of ligands are being reviewed. Examples of such methods encompass the formation of self‐assembled monolayers (SAMs), supported lipid bilayers (SLBs) and polymeric layers on surfaces. Particular emphasis is given to the methods employed in the study of different types of multivalent biological interactions occurring at the functionalized surfaces and their working principles.

中文翻译：

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控制配体密度的表面修饰用于多价生物系统的研究。

在界面多价相互作用的研究中，例如在细胞膜上发生的多价相互作用，界面处显示的配体或受体的密度起着关键作用，影响总体结合亲和力和相互作用所涉及的化合价。为了控制界面处的配体密度，已经开发了几种方法，它们涉及多种材料的功能化。在这里，正在审查用于以受控配体密度进行表面改性的不同方法。此类方法的例子包括在表面形成自组装单层（SAM）、支撑脂质双层（SLB）和聚合物层。特别强调在功能化表面发生的不同类型的多价生物相互作用的研究中所采用的方法及其工作原理。