Innovation

Antibiotic Resistance: Light-Activated Therapy Kills 90% Of Drug Resistant Bacteria

Light
Light therapy could be a huge step forward in the battle against antibiotic resistant bacteria. Mato Rachela (CC BY-SA 2.0)

The battle against drug-resistant bacteria has made its way to the forefront of the word’s public health issues, with deaths because of these bacteria expected to outpace cancer by 2050.

Though the situation is daunting, scientists have been doing their best to fix the problem before it reaches irreparable levels. Efforts have been made to curb antibiotic use in livestock and up the ability of clinicians to distinguish between bacterial and viral infections in order to limit unnecessary use of antibiotics. If preventative methods fail, however, researchers are also looking into new technologies that could take out bacteria once it is already at a problematic level of drug resistance.

Researchers at the University of Colorado Boulder decided to think small to find a solution to the drug-resistant bacteria problem, describing new light-activated nanoparticles called “quantum dots” in a recent paper. The dots, about 20,000 times smaller than a human hair, resemble miniscule semiconductors used in consumer electronics. Despite their size, these quantum dots managed to kill 92 percent of drug-resistant bacterial cells in a lab-grown culture.

“By shrinking these semiconductors down to the nanoscale, we’re able to create highly specific interactions within the cellular environment that only target the infection,” said Prashant Nagpal, an assistant professor in the Department of Chemical and Biological Engineering at CU Boulder and a senior author of the study, in a press release.

Antibiotic resistant bacteria including Salmonella, E. Coli and Staphylococcus kill at least 23,000 people in the U.S. every year. Efforts to thwart these types of bacteria have consistently fallen short, but previous research hinted that metal nanoparticles (created from gold, silver, and other metals) could be effective against antibiotic resistant infections. The problem was they damaged surrounding cells as well, similar to the way chemotherapy destroys healthy cells even though it’s aiming at cancer.

The quantum dots, in contrast, can laser in on particular infections thanks to their light-activated properties. Inactive in darkness, the dots are activated only by a exposing them to light, allowing researchers to alter the wavelength in order to alter and kill infected cells.

“While we can always count on these superbugs to adapt and fight the therapy, we can quickly tailor these quantum dots to come up with a new therapy and therefore fight back faster in this evolutionary race,” explained Nagpal.

The reduction or even elimination of potential side effects of other treatments could be one result of the specificity of the new quantum dot innovation. It could also shine a light (pun intended) on a path forward for future clinical trials and developments.

“Antibiotics are not just a baseline treatment for bacterial infections, but HIV and cancer as well,” said Anushree Catterjee, assistant professor in the Department of Chemical and Biological Engineering at CU Boulder and a senior author of the study. “Failure to develop effective treatments for drug resistant strains is not an option, and that’s what this technology moves closer to solving.”

Source: Courtney C, Goodman S, McDaniel J, Madinger N, Chatterjee A, Nagpal P. Photoexcited quantum dots for killing multidrug-resistant bacteria. Nature Materials. 2016.

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