Antibiotics are widely used medications that can prevent or slow down the growth of bacteria in humans and animals. They can also be added to animal feed to improve growth rates and the effectiveness of the food.
There are significant downsides to their widespread use. If antibiotics are misused or even counterfeited, they can damage a living being’s health, reduce their efficacy, and harm the environment. Researchers at The University of Alabama have developed an easily accessible rapid and portable optical chemical sensor method to detect antibiotic overuse, counterfeiting and pollution in water.
Dr. Marco Bonizzoni, associate professor in The University of Alabama’s Department of Chemistry and Biochemistry, and Yifei Xu, a chemistry graduate student, published their findings in the journal Sensors. Two papers detailing their research appeared in the journal’s special issue, “Sensors and Applications in Diagnostics, Food and Environmental Analysis.”
“We use this family of relatively complex polymers that are called poly(amidoamine), or starburst dendrimers,” said Bonizzoni. “The magic is to combine them with fluorescent dyes in appropriate conditions and proportions that we found optimal. The great part is all of these components are commercially and readily available off the shelf.”
Bonizzoni and Xu developed this method to test for antibiotics in surface water and agricultural runoff downstream from farms. Animal waste winds up in the water, and the chemical sensors can detect if excessive amounts of antibiotics are present.
A dangerous consequence of overuse is forcing natural selection into the bacteria population. Abuse creates multiantibiotic-resistant strands of bacteria. If an overabundance of antibiotics is found in animals, those antibiotics can later wind up in humans after consumption. Similarly, antibiotic-resistant bacteria can then infect the human population as well.
Water samples are already sent to labs for testing on a regular basis, so field testing and determination can reduce the time and resources of shipping and analysis.
“We’re not going to replace a trained chemist in a specialized lab, but we may be able to unburden them,” said Bonizzoni. “Instead of sending them 100 samples, you would send them the 10 that you think are likely to lead to something.”
Bonizzoni said like all drugs for animal or human use, antibiotics are a target for fraud. Their method can give you an idea of whether you actually received the antibiotic listed on the box. Using chemical sensors for instant determination can lead to a more efficient process for regulation and enforcement, particularly when drug components are imported into the United States from another country.
“If a shipment of antibiotics arrives at customs, do I want to block it there and send it out for extra analysis, or do I just release it? If I can do a quick test that says it is probably fine, then you just release it and move on,” said Bonizzoni. “The container doesn’t sit there, and the customer is happy. If you have some doubts, then you fall back on your regular routine.”
Bonizzoni and Xu’s first journal article established their sensor method could be used to detect biomedically relevant targets in water. When it proved successful, they expanded on that idea to show their platform is general enough to be applied to environmental problems as well as the drug counterfeiting issues.
“On one hand, you had very simple, yet very hard to detect carboxylate anions that are elusive targets because they are really small and kind of featureless,” he said. “On the opposite end of the scale, we went with something big and complicated to show that we could do that, too. It just so happens that both of those are interesting in their own right, but to us, they were both opportunities to showcase the fundamental principle of the method that we developed.”
Bonizzoni said the data processing for the field work is very simple and can be done on a smartphone. He hopes to later have an app developed to further enhance their testing, but their chemical sensor recipe for detecting antibiotics in the field is proving successful thus far.
“It has to be portable, simple and pretty robust so it can be used in the field as a point of use and application, so we hit the sweet spot for that because the components of our system are off-the-shelf,” he said. “All you have to do is mix these things according to the recipe we developed, and you have a relatively easy and portable way of detection.”
The Alabama Water Institute contributed funding for these publications.