Cells are the building blocks of all living things. Contained within the cell membrane is all the machinery and information required to sustain and create life, but a machine can’t work without materials. Cells require a constant flow of energy and nutrients across their membrane to stay alive, and this is facilitated by nanoscopic pores or channels in the membrane. These channels are as fundamental to life as the membranes which they span, but they are more complex than simple holes in a sheet. Many of these biological pores are highly specialised, only letting very specific molecules through, and they are some of the most complex structures in the cell: the nuclear pore complex is made up of over 450 individual proteins working together to keep your DNA safe!
A better understanding of these pores and how substances move through them would yield incredible benefits. For instance, antibiotic resistant bacteria stay alive by having specialised pores which eject the antibiotics as soon as they enter the bacterium, and learning how to disable that machinery could lead to huge medical advances. These pores however, are incredibly difficult to study in living cells – an overcrowded, incredibly noisy environment makes observing them in action nearly impossible. So we turn to more simple physical systems to try and better understand what’s happening inside the pores.
One example of these physical systems is glass nanopores – glass tubes which taper to a width of only a few tens of nanometres. They and other solid-state nanopores can already be used to sense single molecules in solution by looking for changes in an electrical current through the pore, but these nanopores contain further hidden information. I am using the noise in the electrical signal to learn more about the workings of the pore itself; by using spectral analysis to study different frequency components in the noise we learn about the mechanisms which govern transport. This technique gives new insight into the physics of the pore, and through it we can learn more about how channel transport works on the smallest scales.
Nanodtc Associate, a2019