UNSW medical researchers have reached broke through previous limitations of resolution capability in single-molecule microscopy. Their key aim was to detect interactions between individual molecules within intact cells. Their research is published in the issue of Science Advances.
Individual molecules can be observed and tracked with super-resolution microscopy today, however, interactions between these molecules occur at a scale at least four times smaller than that resolved by existing single-molecule microscopes.
"The reason why the localization precision of single-molecule microscopes is around 20-30 nanometers normally is because the microscope actually moves while we're detecting that signal. This leads to an uncertainty. With the existing super-resolution instruments, we can't tell whether or not one protein is bound to another protein because the distance between them is shorter than the uncertainty of their positions," stated Professor Katharina Gaus, team leader and Head of UNSW Medicine's EMBL Australia Node in Single Molecule Science.
The team developed autonomous feedback loops inside a single-molecule microscope that detects and re-aligns the optical path and stage.
"It doesn't matter what you do to this microscope, it basically finds its way back with precision under a nanometer. It's a smart microscope. It does all the things that an operator or a service engineer needs to do, and it does that 12 times per second," says Professor Gaus. He continued, "It's a really simple and elegant solution to a major imaging problem. We just built a microscope within a microscope, and all it does is align the main microscope. That the solution we found is simple and practical is a real strength as it would allow easy cloning of the system, and rapid uptake of the new technology".