Scientists have redefined how the key blood‑clotting protein fibrinogen behaves when it contacts air, overturning two decades of scientific consensus on wound healing.
It is the culmination of over a decade of international collaboration by Dr Richard Campbell of The University of Manchester, Professor Juan Ruso of the University of Santiago de Compostela in Spain and Dr Natalia Hassan of the Metropolitan Technological University in Chile.
The discovery could have far reaching implications on the treatment of clotting disorders like haemophilia or the healthcare for patients on blood thinners like warfarin, as scabs forming on the surface of blood are vital to sealing a wound and keeping the site free of infection.
It could also explain aspects of how a lung can collapse in acute respiratory distress syndrome (ARDS), as fibrinogen disrupts the oily layer that keeps the airways open during breathing.
It may also transform the design of biosensors that allow people to monitor how their blood is performing, as the sensors rely on understanding how proteins disrupt those surfaces.
For more than twenty years the field has relied on a 'single tilting layer' model for fibrinogen where the long protein molecules lay flat on the surface at first and then leaned upright as more of them arrive.
But the new study, published in the Journal of the American Chemical Society on today (20/08/25), shows the benchmark model missed that fibrinogen stays lying flat and builds multiple layers that stack like sheets of paper. These layers grow thicker and more complete as more molecules arrive.
This new information helps to explain how the long protein molecules line up on the surface of blood where fibres called fibrin form the basis of the scab, a solid film formed during evaporation of fluid at the blood surface, that seals a wound.
The scientists used an advanced technique called neutron reflectometry at the part-UK-funded Institut Laue-Langevin (ILL) in France, where Dr Campbell was formerly based.
The team demonstrated that this behaviour holds true across multiple ranges of concentration and in very different solution conditions, showing the mechanism is not a rare quirk but a universal feature of fibrinogen when it contacts air.
Principal investigator Dr Campbell explained: "It's never easy challenging an established model of how molecules behave in nature.
"But through using the advanced technique neutron reflectometry on the FIGARO instrument at the ILL research facility, we could see the structure of these protein surfaces in more detail than scientists had seen before.
"Although lab data recorded in the past was compatible with the concept of a 'single tilting layer' model, our new data show multiple layering as a fundamentally different way of working."
Dr Glenn Coope, a former PhD student at The University of Manchester but now based at Lund University in Sweden, said: "When the covid-19 pandemic struck, I spent time analysing structural data of how fibrinogen gathered at liquid surfaces while working from home.
"Then after returning to work at the University, I applied additional experimental methods.
"It's almost like we now have a full circle moment, as our findings may help scientists to understand better the behaviour of fibrinogen in the lungs of patients suffering from ARDS, a condition that tragically claimed so many lives during the pandemic."
Dr Campbell added: "Our discovery sheds new light on how scabs form on the surface of an open wound, where fibrinogen works in a protein‑rich zone to stop bleeding.
"Having better understanding of the structure of fibrinogen at liquid surfaces can only help in the search for new and better treatments for patients whose wound refuse to heal."
- The paper Redefining Fibrinogen Self‑Assembly at the Air-Water Interface: An Intriguing Story with Multiple Layers is published in Journal of the American Chemical Society. DOI https://doi.org/10.1021/jacs.6c11928
- Other researchers from the University of Manchester and Institut Laue-Langevin contributed to the study
