receptor - ligands interaction based on receptor density

Those developing targeted drug therapies aim to recreate this precise binding to develop nano-sized drug carriers that attach only to diseased cells. Once attached, these carriers would release their therapeutic load without affecting healthy cells. If drugs can be specifically targeted in this way, treatments would cause far fewer side effects.

One way to identify which cells are diseased is the number of receptors they express. Cancer cells, for example, tend to express more certain types of receptor than healthy cells.

researchers have demonstrated how a mysterious molecular concept that the authors dubbed 'range selectivity' could be used to target diseased cells with high specificity. Range selectivity, until now a mysterious phenomenon, is where molecules called ligands attach only to cells whose receptors reach a certain number.

"I came across the concept of range selectivity completely by accident. During my theoretical investigation of receptor-ligand binding I noticed that ligands weren't attaching above a certain threshold of receptor density and had my team re-check our code before realizing it wasn't a bug."

In nature, range selectivity happens because of a balance of attractive and repulsive forces at the molecular level. Past a certain threshold the repulsive force must outweigh the attractive, and so binding is far less likely to take place. This is due to certain physical properties of ligand-receptor interactions.

"If we can find out which receptor densities are specific to different diseases and apply what we've demonstrated to drug carriers, we could treat those diseases effectively with fewer side effects."

reference

Meng Liu et al. Combinatorial entropy behaviour leads to range selective binding in ligand-receptor interactions, Nature Communications (2020). DOI: 10.1038/s41467-020-18603-5