Transport of ions, proteins, antibiotics and other macromolecular solutes through channels and pores is ubiquitous in nature.[Link] Channel-facilitated diffusion relies on optimized binding sites for the transported particles inside the channel. A few theoretical studies have rationalized channel-facilitated transport predicting a maximum in the diffusive current with respect to the binding potential.[Link] In order to validate these theories, I built a fully controllable platform combining microfluidics, microscopy and optical tweezers that allowed me to create a synthetic membrane channel that is an analogue of membrane protein pores through which molecules diffuse and demonstrate that there is an optimal pore-molecule interaction that maximises molecular diffusion across the membrane. [Link] These findings are relevant for the design of novel drugs in terms of improved bacterial membrane permeability.