Killing Bacteria With Gold Nanodisks And Light

Scientists at the University of Houston have developed a new method for using gold to kill bacteria. According to the research published in Optical Materials Express, the method could one day help hospitals prevent common infections without relying on antibiotics.
The newly developed method builds on other research demonstrating the ability of gold nanoparticles to reflect infrared radiation to destroy close proximity cellular structures, like bacteria and cancer cells. Using this knowledge, the scientists developed a new type of gold nanoparticle with a disk-like shape and porous structure – which improve heating efficiency and stability.

To measure the antibacterial efficacy of the new “nanodisks,” scientists cultivated E. Coli, as well as two additional types of heat-resistant bacteria and added them to a layer of the nanodisks. When light from an infrared laser hits the nanodisks, they instantly reach 356°F – creating a deadly thermal shock, killing all E. Coli in five seconds and all heat resistant bacteria in 25 seconds. This is a marked improvement over other similar sterilization methods, which can take several minutes or hours.

Currently, the researchers are investigating using the nanodisks as a coating for catheters to help reduce the number of urinary tract infections in hospitals. They’re also exploring the potential of integrating the nanodisks into filtration membranes to improve water quality.

Image Source: “Fig. 2” Greggy M. Santos, Felipe Ibañez de Santi Ferrara, Fusheng Zhao, Debora F. Rodrigues, and Wei-Chuan Shih, “Photothermal inactivation of heat-resistant bacteria on nanoporous gold disk arrays,” Opt. Mater. Express 6, 1217-1229 (2016)

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