Engineering a safer plate

Two years ago, UD professors Erick Vasquez and Yvonne Sun received a $750K grant from the U.S. Department of Agriculture with hopes of minimizing the number of food recalls due to listeria and other contaminants. Vasquez, associate professor of chemical and materials engineering, and Sun, associate professor of biology, are using nanotechnology to create particles coated with disinfectants. Junior Brandon House joined the research team as part of the new Science & Engineering Catalyst Center Summer Fellowship program through the College of Arts and Sciences. Together, they hope to discover a new approach to protecting America’s food.

Yvonne Sun: A big focus of my research is food safety and foodborne pathogens, especially listeria. Listeria can be incredibly hard to eliminate in our food system, even with high-level detection methods in place. If there is detection of any listeria in any part of the food, a recall will need to take place.

Erick Vasquez: My research is focused on sustainable or bio-based nanomaterials, those that are like 100,000 times smaller than the diameter of a hair — things we really cannot see with the naked eye. I’m interested in understanding how these nanomaterials assemble into larger structures, or how can we functionalize or maintain these nanoparticles so they can respond to a certain trigger. For example, with Yvonne, we have been collaborating on demonstrating how disinfectants adsorb onto the surface of the nanomaterials, and testing if they’re efficient in combating listeria.

YS: We’re essentially trying to create tiny weapons; really small and invisible weapons that will be very effective in eliminating foodborne pathogens to promote food safety and health.

EV: We first met as teaching fellows in 2016. We started the conversations about collaborating and working on projects. Yvonne started talking about her work on bacteria and I was like, ‘Oh, I’m more on the materials side, the chemical side.’

YS: Erick is amazing because, to learn more about biology, he took the Biology 151 class. But I have yet to take an engineering class. There’s still time, I suppose.

I work with mostly undergraduates. I teach a lot of prehealth students, so they always want research experience to improve their chances of getting into health professional schools. Brandon House, a junior, is premed and has been very motivated to do research. He is pursuing a new minor offered by the department of biology — research in biological sciences. When he reached out to me this spring saying he wanted to stay in the summer to do research, I said sure. And the College of Arts and Sciences had this new Science & Engineering Catalyst Center Summer fellowship, so it worked out. Luckily, he’s not against working for two mentors because that has its own inherent challenges. In my lab, he’s helped test the activity of antimicrobials, so testing activity of the “weapons.”

EV: In my lab, he has done the chemical synthesis of nanomaterials. The goal with Brandon’s project is to create a completely bio-based nanomaterial; a material that gets a coating of a natural disinfectant chitosan attached to magnetic cellulose nanocrystals, which come from the most bio-available sources in the world, cellulose, which is found in trees. With this hybrid material, we’re looking to disinfect or kill not only listeria but also other bacteria such as E. coli.

YS: I think that the idea of using cellulose is really cool because it’s everywhere. It’s in plants and algae, the clothes we wear, it’s already everywhere. The idea is to use something that’s nontoxic. 

EV: Trying to find something nature-based was the motivation for this project. We have tried toxic disinfectants that worked quite well, but finding something natural has been more challenging — chitosan comes from the shells of crustaceans or shrimp, and that’s kind of exciting; it has antibacterial properties itself.

YS: I’m enjoying and looking forward to more creative collaborations with Erick. Everybody loves food, and I think access to healthy and safe food is definitely a human right. We want to discover new knowledge and then use that new knowledge for good.

EV: After the USDA grant we’re currently working on, we’re going to apply for additional funding, recruit other students, and maybe we can try something else, possibly with eugenol.

YS: Eugenol is a component of clove oil. I think the industry has a lot of interest in essential oils because we just naturally feel like essential oils are healthy and good for us, but we definitely need solid scientific data to support that. 

I really like doing what we do in collaboration. I am trained as a microbiologist, and in science where there’s a very strong apprenticeship model, I can train students with what I know. But I also want them to be trained to do things I can’t do myself. I think it’s really powerful that our students get to be exposed to two different mentors, two different sets of expertise and skills. 

EV: I think this is when collaboration is really helpful, because students get to experience a different model of mentorship and also a different skill set, different knowledge.

YS: Throughout our collaborations, we definitely have reached beyond UD’s campus. We recently hosted an undergraduate student from the University of Texas San Antonio and, this summer, we mentored a student from Ohio State University.

EV: Yes, the Ohio State student has been helping with a lot in both of our labs — from trying a new technique called microwave chemistry to synthesize nanoparticles in my lab to testing activity of the synthesized products in Yvonne’s lab. We have engaged with quite a lot of undergrad students across various majors through our USDA grant, trying to advance this research.

YS: I think at larger universities, the competition for undergraduate students to get research experience is definitely more serious than what we have here, especially in biomedical sciences. They tend to take on students later, in their junior or senior year. But at UD, I’m able to work with first-year students so they can get much longer and extensive research training. I think from the perspective of undergraduate research opportunities, UD is very distinctive.