Submolecular Ligand Size and Spacing for Cell Adhesion

Abstract

Scheme 1. Schematic of submolecular tuning ligand size and spacing to regulate integrin binding and clustering. Descriptions of the proposed model of independently unraveling the effect of ligand size and spacing on integrin ligation and the clustering of macrophages: "7-18", "13-17", "7-3", and "gold shell". In the "A-B" notation, "A" indicates the liganded GNP size in nm and "B" indicates the liganded GNP edge-to-edge spacing in nm. The "7-3" arrays stimulate the binding of integrin across neighboring liganded GNPs, resulting in robust macrophage adhesion comparable to fully liganded gold shells as a positive control. Relative to the "7-3" ligand arrays, increasing the "ligand spacing only" or "both ligand size and spacing" in the "7-18" and "13-17" liganded sites, respectively, yields binding sites for integrin but suppresses multiple integrin molecules joining the neighboring liganded sites due to the "ligand spacing" playing a dominant role, resulting in poor macrophage adhesion.

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