Bruce Lee, an assistant professor of biomedical engineering, focuses on adhesives inspired by nature. More specifically, the natural glues made by mussels that anchor them to rocks, boats and docks. Lee's past work on hydrogels and tissue adhesives led him to look more closely at what makes these adhesives work underwater—and how people could use them.
As a participant in the Office of Naval research’s Young Investigator Program, Lee plans to continue delving into not only what makes mussels sticky but also how to reverse that adhesion.
"This work is novel in the sense that there is no smart adhesive out there that can perform underwater," he says. "The chemistry that we can incorporate into the adhesive, causing it to reversibly bond and de-bond, is quite new."
Adhering to Biomimicry
Lee looks at a specific amino acid found in mussel foot proteins, called DOPA (3,4-dihydroxyphenylalanine), which is related to dopamine. In past research, Lee and his graduate students showed that DOPA could be manipulated to design a hydrogel actuator, which is a mass of jello-like polymers lined with iron bands that enable it to move on its own.
The challenge now is to figure out how to apply an electric current, causing the DOPA-based adhesive to release, and then reapplying the current to make it glue-like again.
"A smart adhesive can bind sensors underwater; it can attach to a ship hull; it potentially could help underwater robotics or unmanned vehicles and integrate with naval systems," Lee says.
He adds there is also a biomedical component: "Think of a band-aid—our adhesive would be a less painful way to remove a bandage—or being able to detach or reattach a prosthetic limb or a wearable sensor."
Sean Kirkpartick, chair of the Department of Biomedical Engineering, says Lee's work is a good example of innovative and creative research.
"The YIP program is one of the most selective research funding programs in the country," he says. "The fact that Lee received this award shows that the faculty and the research programs in the Department of Biomedical Engineering are on par with the best programs in the nation."
To Lee, the key to making this research project work is leaving it fairly open-ended. Basic science is about understanding the mechanism of a phenomenon—in this case, the chemical reactions driving adhesion—then the materials and research can be tailored for more specific uses.
He also says collaboration is an important part of his work and is one of the reasons he received the YIP Award.
"We have a lot of water-focused research going on through the Great Lakes Research Center (GLRC), and I'll have opportunities to collaborate with colleagues on campus," Lee says, adding that he will work closely with Guy Meadows, the center's director, to test the adhesive on underwater autonomous vehicles.
"Lee’s work has the potential to change the way we connect components underwater," Meadows says, explaining that he and other GLRC researchers started working with Lee to attach a camera to a living, five-foot-long Great Lakes sturgeon to learn where they go after spawning.
From following fish to healing wounds to monitoring submarines, Lee's mussel-inspired adhesion research is sure to stick around a while.