Could We Instantly Spot Pathogens By Their Glow?

To figure out which bug is bugging you when you’re sick, there are plenty of ways in the today’s medical lab. But most of them are complicated and can take days.

Xinyu Liu, an assistant professor of chemistry at the University of Pittsburgh, says:

“You can do a swab and culture the bacterium or fungi, but that takes days.You can examine the DNA, but that takes another day or two. It’s a pretty tedious process.

So, before the identity of the pathogen can be determined, doctors give infected people a broad-spectrum antibiotic that kills everything.”

It would be better for the patient, then, to correctly identify the pathogen in question as soon as possible and treat it with a specific antibiotic aimed directly at the offending bug.

Follow The Light

Liu and colleagues have developed a method of identifying pathogens that relies on spectroscopy, determining an object’s identity through the type of light it emits.

They developed a protein hydrogel that interacts with carbohydrates on the surface of a fungus named Candida albicans, which is responsible for oral thrush and skin yeast infection and can be life-threatening for some people.

When the protein hydrogel interacts with the carbohydrates on the surface of C. ablicans, it shrinks the 2D photonic crystals the hydrogel resides on, emitting a specific light signature that can be recognized by the naked eye or a spectroscope. This happens almost immediately.

The researchers say the broader implications are big.

“You can imagine that if we try to extend this work, we can use differing antibodies to make hydrogels tailored for specific pathogens such as staph, E. coli, etc,” the researchers report. “And people living in rural areas or underdeveloped countries might be able to use this method to see if their food or water is contaminated or their kids are infected with deadly pathogens.”

Cai, Z., Kwak, D. H., Punihaole, D., Hong, Z., Velankar, S. S., Liu, X. and Asher, S. A. (2015)
A Photonic Crystal Protein Hydrogel Sensor for Candida albicans.
Angew. Chem. Int. Ed.. doi: 10.1002/anie.201506205