Tiny cracks help 9V-powered coating kill over 80% of bacteria in three hours

Researchers at Flinders University have developed an electrically activated antibacterial coating that uses microscopic cracks in its surface to help destroy dangerous bacteria, including antibiotic-resistant strains.

The flexible material combines liquid gallium, a metal that melts near room temperature, with carbon nanotubes. When the coating dries, tiny cracks naturally form across its surface. Rather than weakening the material, these networks create electrical hotspots that enhance its antibacterial activity.

In laboratory tests, a one-minute electrical stimulation using a standard 9-volt battery killed more than 80% of bacterial cells within three hours, according to the researchers.

The findings could eventually support smart wound dressings, flexible medical devices and wearable technologies designed to help prevent infections without relying solely on antibiotics.

Cracks create electrical hotspots

The international research team, led by scientists at Flinders University’s Biomedical Nanoengineering Laboratory, developed the coating to generate an antibacterial response when activated by a small electrical charge.

As the liquid gallium and carbon nanotube mixture dried, microscopic cracks formed naturally across its surface. The researchers found that these structures concentrated electrical activity into tiny hotspots, helping amplify the material’s ability to damage bacterial cells.

Electrical stimulation increased stress inside the bacteria, contributing to cellular damage and death. The coating could also generate plasma, an energised gas that produces reactive molecules known to suppress bacterial growth.

This combination of electrical and plasma-related effects gives the material its antibacterial properties. The researchers say the cracks can be deliberately incorporated into the coating rather than treated as unwanted defects.

Associate Professor Vi-Khanh Truong from Flinders University’s College of Medicine and Public Health and the Flinders Health and Medical Research Institute said the findings challenge conventional engineering approaches.

“Instead of seeing cracks as defects, we’ve demonstrated they can be designed into materials to create useful functions,” Truong said.

Testing against resistant bacteria

The researchers tested the coating against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Both bacteria can cause serious infections, particularly in healthcare settings and vulnerable patients.

Following just one minute of electrical stimulation, more than 80% of bacterial cells were dead within three hours. Laboratory tests also indicated that the material remained compatible with human skin cells under the conditions examined.

The results suggest the coating could eventually be incorporated into flexible medical devices that deliver antibacterial activity directly at the site of an infection.

Potential applications include wound dressings designed to help protect difficult-to-heal injuries and wearable patches that combine infection prevention with health monitoring. The material can bend, stretch, and conduct electricity, making it potentially suitable for soft skin-mounted devices and smart textiles.

Such systems could one day monitor signals such as heart or muscle activity while providing an additional layer of protection against bacterial growth.

However, the technology remains at an early research stage. The laboratory findings do not establish its safety or effectiveness in patients, and further testing will be needed before it can be considered for medical use.

The research was published in the journal Small Structures.