“We are simply using nature’s idea of producing a specific texture on the surface which makes an implant bactericidal”Saurav Goel

An international team of researchers has reviewed the bactericidal properties of plant and animal surfaces to identify the best way to translate their features for surfaces used in medical implants. As a range of natural surfaces, such as insect wings and lotus leaves, have evolved bactericidal features, mimicking them could help the development of surface structures and chemical compositions for infection-proof engineered implants and other healthcare materials.

By pinpointing how nature has optimized these surfaces the review hopes to inform and improve the design of implant surface treatments capable of offering antibacterial functionality and suppressing bacterial colonization. Although there have been a range of previous research into how natural surfaces manage to kill bacteria in terms of, for instance, chemical reactions, surface roughness and the ability of bacteria to rest on the surface, there have been no commercial applications due to a lack of suitable manufacturing techniques with controlled accuracy on a large scale.

However, as discussed in Applied Physics Reviews [Larrañaga-Altuna et al. Appl. Phys. Rev. (2021) DOI: 10.1063/5.0028844], here the use of a new laser-based approach that can alter the surface properties of a material by manufacturing the desired features in a freeform way using 3D computer models was examined. When the approach is fully developed, it is hoped a prototype of an implant can be made that can then be assessed for its bacterial activity.

The technology is flexible and could be used on all types of prosthetics, a key area where bacterial infections are problematic. Although infections brought about by implants are relatively rare, the dramatic increase in prosthetic use means the number of infections is growing, bringing enormous cost to healthcare. Also, the treatment of implant infections can be problematic due to the growth of bacterial biofilms on implant surfaces, which create a barrier that protects the infecting organisms from host immune defenses and exogenous antibiotics.

The work highlights the manufacturing challenges, and the need of sub-nanometer precision in the manufacturing approach, and they laser technology and new computer-aided designs used can automate the manufacturing process. As researcher Saurav Goel said, “We are simply using nature’s idea of producing a specific texture on the surface which makes an implant bactericidal”.

The team are now exploring technology to transfer the concept of laser processing from flat surfaces to circular surfaces to mimic these shapes on pre-machined complex shapes, and also to optimise the processing parameters to use a wide range of materials, including ceramics and glass, which could help in the development of bactericidal touch screens for smartphones.

Nature-inspired bactericidal surfaces
Nature-inspired bactericidal surfaces