An Italian study published in Nature Communications shows that shaping the surface of stents and catheters can reduce bacterial adhesion by up to 90%. A physical strategy, inspired by sharks and dragonflies, to combat biofilm and antibiotic resistance.
Medical device-related infections represent one of the most critical challenges for modern healthcare. There are an estimated over 50 million healthcare-related infections worldwide each year, and more than 60% are associated with the formation of bacterial biofilmsstructures that make microorganisms more resistant to antibiotics. Catheters, stents and implants, in continuous contact with blood, urine and other body fluids, become ideal surfaces for pathogens to take root. Today, however, Italian research proposes a paradigm shift: not to intervene on the chemistry of materials, but on theirs microscopic form. The research was conducted by Roberto Rusconihead of the Applied Physics, Biophysics and Microfluidics unit at the IRCCS Istituto Clinico Humanitas and associate professor of Physics for life sciences, the environment and cultural heritage at Humanitas University, and by Luca Pellegrinopostdoctoral researcher in the same laboratory. The study shows that particular surface corrugations can prevent bacteria from stabilizing, simply exploiting the natural flow of body fluids to “sweep them away”.
From chemistry to physics: surfaces inspired by sharks and dragonflies
Until now, infection prevention on medical devices has mainly relied on antimicrobial coatings or chemical modifications of materials. The new data instead adds a decisive element: the surface geometry. The idea was born by observing nature. Shark skin is characterized by tiny grooves micrometric which limit the accumulation of microorganisms favoring their detachment; Dragonfly wings have nanometric structures capable of even physically damaging bacteria. Applying these principles, the researchers created corrugated surfaces in PDMS (a silicone polymer widely used in the biomedical field), obtained through controlled stretching and physical phenomena of instability called “buckling”similar to the folds that form on compressed skin. The micro-ripples created in the laboratory were then tested in dynamic conditions that faithfully reproduce the flow of body fluids, overcoming traditional static experiments that are not very representative of clinical reality. The principle is purely mechanical: if a surface does not offer a stable anchoring point, the bacteria are continually lifted and dragged away by the flow. The microscopic curvatures act as a physical barrier which hinders initial adhesion, a crucial step for biofilm formation.
Reduction of bacterial adhesion by over 90%
The results are significant: certain configurations of “wrinkles” approximately five micrometers wide reduced bacterial adhesion by more than 90%. The effect was observed by varying the flow conditions and testing two pathogens of great clinical impact, Pseudomonas aeruginosa and Staphylococcus aureusfrequently involved in hospital infections linked to catheters, stents and endotracheal tubes. A key aspect of the study is that the chemical composition of the surfaces remained unchanged: the decrease in colonization is attributable exclusively to geometric structure. This paves the way for medical devices designed to be intrinsically anti-biofilm, without resorting to drugs or coatings that can lose effectiveness over time and promote antibiotic resistance phenomena. The checks were carried out with very high resolution microscopy techniques, capable of analyzing details down to a millionth of a millimetre, integrating dynamic observations of the bacteria with structural images of the surfaces. The perspective is clear: design catheters and stents with optimized micro-geometries it could drastically reduce infections related to medical devices, improving patient safety and offering a concrete response to the growing threat of antibiotic resistance. In this scenario, surface physics is a candidate to become a new ally of medicine.
