How do disinfectants destroy bacteria?
24 Sep 2026 - Rosie de Laune
An academic/industrial partnership has investigated the methods behind the antimicrobial activity of two types of disinfectant, finding they are more effective when used together.
Disinfectants are a key tool for fighting disease and infection. Effective disinfection of public facilities reduces the cross-contamination of transferable diseases, thereby cutting down the needs for hospitalisation and antibiotic treatment. However, despite their widespread critical use, there is little understanding of how they work.
A team, led by researchers from the University of Manchester in collaboration with their industrial partner Arxada and ISIS scientists, have used a range of techniques to study the interactions between a typical disinfectant and microbial membranes. Their collaboration was funded through a BBSRC Prosperity Partnership award.
For a company like Arxada, the ability to access state-of-the-art facilities such as STFC's ISIS neutron and muon source and collaborate with world-leading project scientists has provided invaluable insights into how our biocides function at the most fundamental level.
Arxada
In their study, published in the Journal of Colloid and Interface Science, they report the investigation into the antimicrobial mechanisms of two representative disinfectant surfactants: the cationic didecyldimethyl ammonium chloride (DDAC) and the non-ionic hexaethylene glycol monododecyl ether (C12E6).
They looked at their antimicrobial activity, individually and combined, against Gram-negative bacteria. To gain further insights into the mechanism behind this activity, they studied their interactions with model lipid bilayers using multiple techniques including small-angle neutron scattering (SANS) on Zoom, and neutron reflectivity (NR) on Inter, OffSpec and at the ILL. Working closely with the ISIS deuteration laboratory, they used a range of selective deuteration to gain a detailed picture of how the two surfactants interact with both inner and outer bacterial membranes.
They found that C12E6 binds to the outer membrane and partially inserts into the inner membrane of Gram-negative E. coli, causing mild destabilisation but no significant membrane disruption. In contrast, DDAC strongly binds and inserts into both outer and inner membranes, leading to effective membrane leakage and cell damage, which is what you need from a disinfectant. When the two are combined, C12E6 facilitates DDAC insertion, enhancing membrane disruption. However, excess C12E6 decelerates the bacterial killing power of DDAC.
“The different molecular interactions revealed by the neutron experiments and biophysical assays help us to understand the roles of different surfactants in a formulated product, by linking their membrane disruptive behaviour with their antimicrobial efficacy,” explains Professor Jian Lu, the lead author of the paper. “This paves the way forward for new product formulations in our fight against antimicrobial resistance.”
“The BBSRC STFC Facility Access Fund has been absolutely critical in allowing us to move quickly and with confidence in this area of research,” say Arxada. “For a company like Arxada, the ability to access state-of-the-art facilities such as STFC’s ISIS neutron and muon source and collaborate with world-leading project scientists has provided invaluable insights into how our biocides function at the most fundamental level. These grants not only enabled us to validate our hypotheses and demonstrate feasibility, but were also instrumental in securing the Prosperity Partnership. We are excited to continue this collaboration with the University of Manchester and UKRI facilities, tackling one of the most urgent scientific and societal challenges of our time.”
The full paper can be found at DOI: 10.1016/j.jcis.2025.137891
