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Light-activated oxygen could kill antibiotic-resistant bacteria

Research presented at the 256th National Meeting of the American Chemical Society suggests treatment-resistant MRSA could be targeted by light-activated oxygen.

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Aug 19, 2018
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University of Cincinnati (OH, USA) researchers have developed a novel method to treat antibiotic-resistant bacterial infections. The research, presented at ACS Boston 2018 (MA, USA; 19–23 August 2018), highlights the use of light to activate oxygen to target the bacteria, and could be used to treat a range of microbial infections and potentially cancer.

Methicillin-resistant Staphylococcus aureus (MRSA) is a life-threatening bacterial infection that can devastate hospitals due to its resistance to antibiotics. A recent study suggested that if every patient admitted to an acute-care setting was disinfected, the rate of bloodstream infections would be reduced by 50%, however, this is not feasible.

“Instead of resorting to antibiotics, which no longer work against some bacteria like MRSA, we use photosensitizers, mostly dye molecules, that become excited when illuminated with light,” commented Peng Zhang, Associate Professor of Chemistry & Materials Science at the University of Cincinnati.

“Then, the photosensitizers convert oxygen into reactive oxygen species that attack the bacteria.”

The team set out to design a novel hybrid photosensitizer that was water-dispersible. The compound includes noble metal nanoparticles that are studded with amphiphilic polymers to entrap the molecular photosensitizers.

The findings suggest that this photosensitizer was much more effective at killing bacteria than those designed without metal particles. These particles are thought to provide two benefits: they have a ‘plasmonic enhancement effect’, which promotes the generation of reactive oxygen species, and also concentrate the photosensitizers in one place to provide a localized hit to the bacterial cells.

“If you want to attack a castle, and you just let all these people attack individually, it is not very effective. Instead, if you have the same number of people grouped together attacking the castle at one point, it is possible to cause more damage,” Zhang added.

The hybrid photosensitizers can be formulated into a spray or gel and illuminated with either blue or red light to disinfect the surface. The method is also thought to show promise in the treatment of wounds to eliminate infection, as the photosensitizer was not found to damage skin cells.

Furthermore, the team hope the nanoparticles could be used for the treatment of cancer. According to Zhang, the nanoparticles are ideal for destroying skin cancer cells, as they perform effectively under red light illumination, which has a long wavelength and can penetrate deep into the skin – this is important for an effective skin cancer treatment. The nanoparticles could also be used to treat fungal infections. 


Source: Zhang P. Weaponizing oxygen to kill infections and disease. ACS National Meeting and Exposition (19–23 August 2018; MA, USA) 

Go to the profile of Jasmine Harris

Jasmine Harris

Digital Editor, Future Science Group

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