Etched aluminum capable of killing bacteria including drug-resistant strains
14 Dec 2017
By Dr. Jafar Hasan, Early Career Fellow
Indian Institute of Science, Bangalore
To combat hospital-acquired infections (HAI) or “nosocomial” infection, our research group has etched commercially available aluminum alloys to generate micro- and nanoscale roughness on the surfaces, inspired by insect wing surfaces that ward off bacteria including drug-resistant strains.
Antimicrobial resistance (AMR) is a one of the biggest health threats of this century. Microorganisms such as viruses, bacteria, fungi etc. that become resistant to the toxic effects of drugs are called drug-resistant microbes. Drug-resistant bacteria are the cause of many infections in sensitive areas of hospitals in India such as ICUs, operation theatres, hospital beds, sinks, toilets, door knobs, elevator, and other instruments used by doctors and the hospital staff. According to WHO, of every 100 hospitalized patients at any given time, 7 in developed and 10 in developing countries will acquire at least one HAI. This highlights the need for better hospital hygeine practices as well as material that can be used to make bacteria-resistant medical equipments to reduce spread of infections.
We have developed etched aluminum surfaces that were found to kill as well as repel wide range of disease-causing as well as drug-resistant bacterial strains- 82 % of E. coli, 25 % of K. pneumoniae and 86 % of P. aeruginosa. The etched alloy surface also reduced the number of S. aureus cells to one-tenth of the attached cells on the control alloy surface. In general, the surface roughness induced at microscale was able to resist the bacterial attachment whereas the multi-scale roughness, especially the nanostructures, imparts a bactericidal property to the surface. The fabrication method of etching is also shown to be easily scalable for industrial applications where larger area of A4 size aluminum sheets were fabricated with the same surface topography. Roughness measurements on the surfaces followed by statistical analysis revealed that specific ranged values of several parameters can yield a highly bactericidal surface; thereby providing the design to make an efficient bactericidal surface irrespective of the method of fabrication. It is predicted that such engineered surfaces with multi-scale topography can help to minimize spread of bacterial infections especially in the hospital environment.
(Ref: Materials & Design)
Multi-scale surface topography to minimize adherence and viability of nosocomial drug-resistant bacteria. Jafar Hasan, Shubham Jain, Rinsha Padmarajan, Swathi Purighalla, Vasan K. Sambandamurthy,Kaushik Chatterjee. Materials & Design. November 2017.
Banner image: Photograph of etched alumnium surface showing dead bacteria