A Nanoadhesive Composed of Receptor-Ligand Bonds

A gap exists in the adhesive landscape for adhesives that bind strongly, yet reversibly in aqueous environments such as those found at tissue surfaces. Many cells and organisms such as the bacteria Escherichia coli have evolved sophisticated mechanisms to achieve just this ability. In this paper, we begin to investigate whether E. coli's mannose-binding FimH receptor and associated fimbrial linkage can be harnessed to create a reversible wet adhesive. Atomic force microscopy is used to measure adhesive interactions between a polystyrene sphere coated with a thin film containing mannose and a planar polystyrene surface coated with a thin film containing FimH. Adhesion maintained 70% of its original strength through 200 consecutive interactions at the same location. The adhesive was also non-fouling as demonstrated by the return of adhesion after addition and removal of a soluble inhibitor. Incorporation of the fimbrial linkages into the adhesive surfaces allowed adhesion to scale better to larger sizes and provided adhesive lifetimes >1800 times longer. These results reveal some intriguing characteristics of a nanoadhesive comprised of many parallel bonds anchored by force-absorbing linkers and provide strong motivation for the continued research on such receptor-ligand based adhesives.