An international team of scientists have discovered that soap - just like the type we use to wash our hands - could be important to helping our understanding of complex systems in the human body, such as lungs, and improving therapies for conditions such as respiratory distress syndrome.
In the last few years, researchers have found that surfactants-the molecules found in soap-can naturally find its way through a maze using the shortest path, with little penetration into dead ends
The discovery may sound a little peculiar, but the finding mimics transport processes in complex branching networks found in the human body, such as lungs. It may hold the key to understanding how liquids, such as certain drugs, travel through these networks, which could help medical scientists find new and more effective therapies.
Now, scientists at The University of Manchester, working with colleagues from France and the US, have published a theory in the journal Physical Review Letters explaining the phenomenon.
Dr Richard Mcnair, Research Associate in the Department of Mathematics at The University of Manchester, said: "When we put soap into a liquid filled maze, the natural surfactants already present in the liquid interact, creating an omniscient view of the maze, so the soap can intuitively find the correct path, ignoring all other irrelevant paths.
"This behaviour occurs due to very subtle but powerful physics where the two types of surfactants generate tension forces that guide the soap to the exit."
The researchers used advanced mathematical models and simulations to replicate how these forces gather an awareness of the maze's overall shape and structure. The mechanism can help scientists understand how materials move in confined spaces in complex, branching environments.
Surfactants are substances that help fluids spread. They naturally exist in the human lungs and when doctors treat lung diseases, they sometimes use "exogenous surfactants" (from external sources) to help the lungs work better. However, the surfactants already in the lungs can interfere with these treatments, making it harder for the added surfactant to travel around the airways to where they are most needed.
This research helps scientists understand why surfactant therapies might not always work as expected, especially for diseases like acute respiratory distress syndrome (ARDS), which has a high mortality rate and may be able to design more effective therapies.
Dr Mcnair said: "But the applications of this research doesn't stop there. Many other systems such as microfluidic devices that transport chemicals and other substances through intricate networks could benefit from this insight for informing better designs for these systems, inevitably improving efficiency and reducing costs."
The research team has already developed preliminary models involving surfactants spreading in realistic lung-scale geometries which could directly connect the findings of this research to clinically important research.
