Could an insect-protein coating block bacteria on medical implants?

Despite infection controls and sterilisation, bacteria is often found on implants following surgery, which can lead to infections requiring antibiotics. And with antibiotic resistance becoming more common, new preventative measures are needed. Now, an Australian team of researchers — led by RMIT University — have achieved the first reported use of antibacterial coatings made from resilin-mimetic proteins to fully block bacteria from attaching to a surface. It marks a critical step towards the creation of ‘smart surfaces’ that can stop dangerous bacteria — antibiotic-resistant ones like MRSA especially — from growing on medical implants.

“This work shows how these coatings can be adjusted to effectively fight bacteria — not just in the short term, but possibly over a long period,” the study’s lead author Professor Namita Roy Choudhury from RMIT said. “Antibiotic resistance has prompted greater interest in the area of self-sterilising materials and easy preparation of antibacterial surfaces,” Choudhury added. “Therefore, we designed this surface to completely prevent the initial attachment of the bacteria and biofilm formation to decrease the infection rates.”

Applications of such a surface include spray coatings for surgical tools, medical implants, catheters and wound dressings. The protein at the centre of this study — resilin — is known for its elasticity, which allows fleas to leap more than one hundred times their own height in microseconds, and is also known as a biocompatible and resilient protein. "These exceptional properties and non-toxic nature make resilin and resilin-mimetic proteins ideal for many applications requiring flexible, durable materials and coatings,” Choudhury said.

The antibacterial surface magnified 4000 times under scanning electron microscope, showing the topographical feature of the coacervate resilin-mimetic coating on the base scaffold substrate.

Several forms of coating were created from altered forms of resilin, which were then tested through interaction with E.coli bacteria and human skin cells in lab conditions. What was revealed is that the altered proteins — in nano droplet form, known as coacervates — were 100% effective at repelling the bacteria, while still integrating well with healthy human cells, as is a critical part of medical implant success. “Once they come in contact, the coating interacts with the negatively charged bacterial cell membranes through electrostatic forces, disrupting their integrity, leading to leakage of cellular contents and eventual cell death,” RMIT’s Dr Nisal Wanasingha said.

The study — titled ‘Nano-structured antibiofilm coatings based on recombinant resilin’ — was published this year in Advances in Colloid and Interface Science (doi.org/10.1016/j.cis.2025.103530). As to next steps, RMIT’s Professor Naba Dutta said: "These early results are very promising as a new way to help improve infection control in hospitals and other medical settings, but now more testing is needed to see how these coatings work against a wider range of harmful bacteria.” Dutta adding: “Future work includes attaching antimicrobial peptide segments during recombinant synthesis of resilin-mimics and incorporating additional antimicrobial agents to broaden the spectrum of activity.”

Top image caption: The team: Dr Nisal Wanasingha, Professor Namita Roy Choudhury, Professor Naba Dutta and Dr Jitendra Mata with Quokka, the small angle neutron scattering instrument at the Australian Centre for Neutron Scattering. Credit: ANSTO