Student researchers first with discovery in photochemical sciences
Orange peel and kelp, sugars and iron salts — not the ingredients one might expect to find in a sophisticated, photochemistry-based drug-delivery system. Yet student researchers at BGSU have discovered that polymers of these relatively simple substances are well suited as carriers for drugs that will be released when activated by light.
The American Chemical Society journal Applied Materials and Interfaces has published an article by Giuseppe Giammanco, a third-year Ph.D. student from Venezuela, and Christopher Sosnofsky, a senior from Michigan majoring in chemistry. Both are students in the lab of Dr. Alexis Ostrowski, an assistant professor of photochemical sciences.
"Light-Responsive Iron(111)—Polysaccharide Coordination Hydrogels for Controlled Delivery" is online now and will appear in the next print edition of the journal.
The team is the first to demonstrate that molecules created from nontoxic, biocompatible materials can be made responsive to light, Ostrowski said. “The intriguing thing is we’ve shown we can make advanced materials from scratch using readily available substances,” she said. “This is a sustainable approach for drug-delivery systems.”
Giammanco and Sosnofsky used a process of ionic gelation to cause the iron salt polymers to gel into microspheres. Those particles can encapsulate a variety of drugs.
“They’re very versatile,” Sosnofsky said. The team has experimented with two antibiotics and folic acid, along with simple dyes that enable them to see the progress of the reaction.
Once ingested, the polymer “capsules” remain stable until irradiated with light, which can be applied only in the area needed. “This limits drug exposure,” Sosnofsky said, which is helpful for avoiding unwanted side effects.
In addition, “We use visible light, and no powerful lasers,” Giammanco said. “These are LEDs, not UV light, which is harmful. We apply the light to cause the capsules to become leaky and start releasing their cargo.”
Sosnofsky, who plans to attend medical school after he graduates in May, said, “This sheds light on the impact researchers can have on the medical field.”
Using alginate from brown algae and pectin from orange peel, the team crafted the solid materials. And although it is a good thing the materials are so safe and biodegradable, they are almost “too friendly” to the body, Ostrowski said.
“They’re so biocompatible and so similar to food that we think they will be absorbed or digested before we can irradiate them,” she said. “We’re designing new materials that are similar enough not to be rejected but different enough to not be so readily absorbed.”
Giammanco and Sosnofsky are already working on that, and have observed changes in the polymers’ responsiveness to light according to changes in the types of sugars used. Having this information will enable researchers to design carriers for either slow- or quick-release drug delivery.
“We’re doing a quantitative study,” Ostrowski said. “The type of sugar is important for how quickly they release. This has definitely not been done before.”
Instead of the proverbial “eureka” moment, the scientists said, they at first could not believe the results they were seeing with the pectin and brown algae from kelp.
“Chemically, they should have reacted exactly the same, but one reacted to light 10 times faster,” Ostrowski said. “We had to repeat it many, many times until we were convinced.
“We see this as a ‘proof of concept,’” she said. “Now we’ll collaborate with other people to do additional studies and refine it.”
As is typical, the article went through two rounds of peer review by other scientists before being accepted for publication in the journal. “Its being published shows its value,” said Giammanco, who is preparing for a career in photochemistry research either in academia or industry.
The journal article is the first of two to come out of the Ostrowski lab already this year. The second, whose first author is undergraduate Jon Mase, a senior majoring in chemistry, also deals with light-responsive materials. Mase is working with graduate students Anton Razgoniaev and Dayana Muizzi on perfecting a nitric oxide-releasing polymer that will react to near-infrared light, which is not damaging to cells and penetrates the deepest into tissue.
Both projects have been supported by internal grants from BGSU’s Office of Research and Economic Development, the College of Arts and Sciences and its dean’s office, and the Department of Chemistry. Sosnofsky and Mase have received funding through the Center for Undergraduate Research and Scholarship.
“It’s great when your hard work pays off,” Sosnofsky observed.
With the publication of the two articles, Ostrowski will pursue funding from the National Science Foundation to continue the photochemical research.