A new nanoscopy technique developed at The Australian National University (ANU) has uncovered hidden networks used for communication between cells, opening new ways to understand human diseases.
Published in Nature Communications, the breakthrough allows researchers to observe how living cells interact with their environment over several days, revealing three-dimensional behaviours that were previously invisible to conventional microscopes.
"Using gentle, label-free imaging means we can finally witness the secret, dynamic life of cells in real time and 3D," said senior investigator Dr Steve Lee from the John Curtin School of Medical Research (JCSMR) at ANU.
"The technique allows for faster and more accurate breakthroughs in how we understand and treat human disease at the nanoscale."
The team used the new method, RO-iSCAT, to observe thin, thread-like nanoscale extensions from cells. Over days of continuous imaging, these structures were seen extending, retracting and reconnecting, forming intricate networks that transfer biochemical messages to neighbouring cells.
Lead author and PhD researcher Junyu Liu helped develop the new nanoscopy technique by rotating the angle of light illuminating the sample and combining images at different heights.
"Under rotational illumination, the background noise is stripped away, revealing various nanoscale cellular structures in three dimensions," Mr Liu said.
The team began experimenting with how the three-dimensional tracking technique can measure the often elusive, thread-like cellular nanoscale extensions, which are critical for almost all cellular signalling, communication, and movement.
"Our technique boosts a nearly undetectable amount of light signal bouncing off living cells by tenfold in real time," Dr Lee said.
"It's incredible that this technique doesn't require the use of chemical dyes, or 'labels', that are ubiquitous in nanoscopes but can be toxic to the very cells they are studying due to phototoxicity."
Footage from the research revealed that these connections are not as static as previously thought. In highly dynamic motion, the structures twist around each other before forming a stable bridge.
Dr Daniel Lim, a senior imaging scientist in the team, quickly used their new capability to investigate different cell types from researchers at the Garvan Institute of Medical Research and within the JCSMR. This included investigating how pancreatic cancer cells and human blood vessel cells form multiple 'tight' bridges with the surrounding connective tissue cells. These interactions are thought to help tumours grow and resist treatment by shaping their local environment or assist in in forming new blood cells.
The same approach could also help scientists understand how viruses move between cells, as some are thought to spread through these cellular bridges.
"Now we have the tool to better understand these nanoscale interactions within larger cell populations," Dr Lim said.
"This could help us learn how to block specific pathways to treat diseases or deliver drug therapies more precisely."
The paper, Using rotational integration of oblique interferometric scattering to track axial spatiotemporal responses of tubular membrane protrusions, is published in Nature Communications.
