PNNL

Abstract

The generation of an electrochemical pH gradient across biological membranes using energy from photosynthesis and respiration provides the universal driving force in cells for the production of adenosine triphosphate (ATP), the energy unit of life.[1] Creating such an electrochemical potential requires the transportation of protons against a thermodynamic gradient. In biological proton pumps, chemical energy is used to induce protein conformational changes during each catalytic cycle where one or a few protons are pumped against a proton concentration gradient across the membrane. On the other hand, membrane channels also exist that mediate continuous particle exchange and may be switched between open and closed states.[2–7] Being able to design nanochannels with similar functions would be of great importance for creating novel molecular devices with a wide range of applications such as molecular motors,[8–11] fuel cells,[12] rechargeable nanobatteries that provide energy to other nanomachines,[13] and the generation of locally and temporally controlled pH jumps on microfluidic chips.