21 March 2016

Antimicrobial nanoparticles

Gold nanoparticles and light kill bacteria in seconds

Alexander Kornev, Naked Science

Researchers from the University of Houston have developed a new technique for killing bacteria in a matter of seconds using gold nanodiscs and light. Scientists hope that their method in the future will be able to help doctors in the treatment of some common infections without the use of antibiotics.

"We showed that all the bacteria were killed pretty quickly: from 5 to 25 seconds. This is a very fast process," Wei–Huang Shi, the lead author of the study, is quoted by the Science Daily portal (New technique for rapidly killing bacteria using tiny gold disks and light).

Scientists have created nanoparticles in the laboratory by dissolving gold and reducing the metal to nanometer sizes. The diameter of a human hair ranges from 50 thousand to 100 thousand nm. Previous studies show that gold nanoparticles strongly absorb light, quickly converting photons into heat that can destroy various types of cells, including cancer cells and bacteria.

In 2013, Professor Shi and colleagues created a new type of gold disk-shaped nanoparticles that were permeated with pores, which helped to increase their heating efficiency while maintaining their stability. In the new work, the scientists decided to test the antimicrobial properties of these nanoparticles when activated by light. They grew various bacteria in the laboratory, including E. coli and two types of heat-resistant bacteria.

The researchers then placed the cells of these bacteria on the surface of a single-layer coating of tiny disks and directed infrared light from a laser at them.


Using a thermal imager, the scientists showed that the surface temperature of the particles rose to 180 degrees Celsius almost instantly. As a result, according to the researchers, all bacterial cells were killed within 25 seconds. E. coli was the most vulnerable – it took only 5 seconds to destroy it. 

Portal "Eternal youth" http://vechnayamolodost.ru  21.03.2016

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