October 17, 2016 10:00AM
Researchers at Pittsburg State University have developed a process that may one day make a night out at your favorite restaurant, a trip to the grocery store or turning on the tap in a developing nation a much safer experience.
Tuhina Banerjee, a chemist in PSU’s Department of Chemistry, along with Assistant Professor Santimukul Santra, Professor James McAfee, and six students in the department, combined magnetic resonance imaging (MRI) and fluorescence to create a device that enables scientists to detect the presence of dangerous bacteria in food and water, and to do so in less than an hour.
Their research was published recently in the American Chemistry Society (ACS) journal, Infectious Diseases.
The research has major implications because bacterial contamination of food and water is one of the world’s leading causes of sickness and death. In the U.S., one in six Americans will get sick this year from a foodborne illness, according to the Centers for Disease Control. Of those 48 million, more than 125,000 will be hospitalized and 3,000 will die.
The culprit is often E. coli, a large group of bacteria that surround us every day. Most are harmless, but some, like E. coli 0157: H7, are very dangerous, as companies like Costco and Chipotle have discovered at great cost.
Banerjee said she has seen first-hand how serious these bacterial outbreaks can be.
“Dr. Santra and I are both from India, where cholera has sometimes spread because of contaminated water supplies,” Banerjee said.
Santra, who came to PSU as part of its Polymer Chemistry Initiative, said news stories about E. coli contamination of foods in the U.S. inspired the PSU researchers to think about using nanosensors to try to detect common pathogens, first in water.
The nanosensors are made up of iron oxide particles combined with an optical dye and antibodies that latch onto the E. coli cells. The nanosensors clump around the bacteria and this can be detected by MRI, for very small amounts, and fluorescence, for large amounts.
The researchers began by testing water from PSU’s University Lake and from a number of other sources.
“We found that the nanosenor is very good at picking up contaminations,” Santra said.
For their research, Banerjee and Santra, teamed up with Professor James McAfee, a biochemist in the department.
“A very important part of the collaboration was his very insightful questions,” Santra said.
Additionally, six students assisted in the research and the senior researchers said their help was crucial.
“The time commitment research takes is challenging,” Banerjee said. “Some things have to be checked or measured frequently. Shoukath Sulthana, Tyler Shelby and the other students could be in the lab on weekends or after hours to make this project successful.”
“The students are very hard working,” Santra added. “I’ll ask for something and they’ll get it done in a timely manner.”
Sulthana, a graduate student in polymer chemistry and Shelby, an undergraduate student in chemistry, who worked on developing the new bacterial contamination detector, said the research experience they’ve had at PSU is invaluable.
“I think it goes back to what makes this place special,” Shelby said. “I don’t know where else you would have the contact time with professors that we do here. I’ve spent countless hours in professors’ labs, talking to them about what they’re working on.”
Shelby is a recipient of the Star Trainee Award from the Kansas IDeA Network of Biomedical Research Excellence (K-INBRE) and he is following up the research on E. coli with a paper that explores how nanosensors may be used for the rapid detection of the Influenza virus.
McAfee said Shelby’s PSU experience will be a big boost as Shelby applies to MD/Ph.D. programs.
“Having done this research and having a paper published in a highly regarded journal is worth a thousand A’s,” McAfee said. “That’s one of the reasons that having students involved in this type of research is so important.”
Banerjee said that since the researchers published their work, they have been getting calls from researchers around the world. The work was described in an American Chemical Society press release and was reported in several scientific news magazines. Recently, Banerjee received an invitation to present a talk at the 2017 International Food Technology Conference in Las Vegas. In addition, the researchers have been asked to submit an editorial article for the journal Future Microbiology, which they have done.
The next step, in order to make a rapid detection system available in the field, is miniaturization.
“The next step is to work with engineers to develop a chip that can take the process out of the lab and into the field,” Banerjee said.
In the meantime, the researchers are exploring ways the technique they’ve developed could be used for the rapid detection of other pathogens, such as influenza and Zika.
Below: Tyler Shelby runs a water sample through the MRI in search of E. coli bacteria.