Scientists unlock nature's secret to super-selective binding

Visualization of protein complexity on a cell surface (© PBL EPFL/Christine Lavanchy) - Researchers have discovered that it is not just molecular density, but also pattern and structural rigidity, that control super-selective binding interactions between nanomaterials and protein surfaces. The breakthrough could help optimize existing approaches to virus prevention and cancer detection. So much of biology comes down to the biophysical process of binding: making a strong connection between one or more groups of atoms - known as ligands - to their corresponding receptor molecule on a surface. A binding event is the first fundamental process that allows a virus to infect a host, or chemotherapy to fight cancer. But binding interactions - at least, our understanding of them - have a 'Goldilocks problem': too few ligands on one molecule makes it impossible for it to stably bind with the correct target, while too many can result in undesirable side-effects. "When binding is triggered by a threshold density of target receptors, we call this "super-selective" binding, which is key to preventing random interactions that could dysregulate biological function," explains Maartje Bastings, head of the Programmable Biomaterials Laboratory in the School of Engineering. "Since nature typically doesn't overcomplicate things, we wanted to know the minimum number of binding interactions that would still allow for super-selective binding to occur.