Novel nanoparticles machined by laser could provide a method for combating the increasing problem of antimicrobial resistance. Researchers at the University of Manchester in the UK have produced new forms of nanoparticles using picosecond laser ablation that have a more effective antibacterial function.
The work was presented by Professor Lin Li, director of the Laser Processing Research Centre at the University of Manchester, at the Association of Laser Users’ (AILU) biennial Industrial Laser Applications Symposium (ILAS), which took place 17-18 March in Kenilworth, UK.
The World Health Organisation in a 2014 report estimates that antimicrobial resistance causes 25,000 deaths per year in the EU in a population of 500 million, with 2.5 million extra hospital days at an overall cost to society of approximately €1.5 billion per year. WHO states that ‘a post-antibiotic era – in which common infections and minor injuries can kill – far from being an apocalyptic fantasy, is instead a very real possibility for the 21st century.’
‘The message is that we’re running out of drugs to treat resistant bacteria,’ commented Li at the ILAS conference. Nanoparticles ranging from 1-100nm in size made of metals like gold or silver have been shown to kill bacteria without causing resistance. The disadvantage of these particles is that many are harmful to human cells.
The nanoparticles interact or are ingested by the bacteria resulting in cell death. The nanoparticles produced by Li’s team include TiO2 or AgTiO2 machined by a picosecond laser. The new forms of nanoparticles were effective at killing Escherichia coli and Staphylococcus strains of bacteria, while at the same time exhibiting lower toxicity to human endothelial cells than water.
The researchers also experimented with using a femtosecond laser to ablate the nanoparticles to give much smaller particle sizes, but these were found to be less effective than the larger picosecond lased particles.