The Langmuir Lectures: Of Colloids and Mussels

Yesterday afternoon, I attended the Langmuir Award Lectures, a session the Division of Colloid & Surface Chemistry has been hosting for well over 20 years, according to presider Deborah Leckband.

This year’s awards went to Jennifer A. Lewis of the University of Illinois, Urbana-Champaign, and Phillip B. Messersmith of Northwestern University. Each gave an overview of the research that garnered them the award, interspersed with tantalizing bits of unpublished results. The differences in their presentations, though, interested me almost as much as the award-winning research.

Lewis talked at a rapid-fire pace about using colloidal particles for patterning and printing, cramming a lot of information into her lecture on “dry” chemistry. In contrast, Messersmith methodically presented some “wet” chemical research on biomimetic coatings and adhesives inspired by ocean-dwelling mussels. Because of his slower pace, he had to skip over a few slides to take questions. Both presentation styles worked—and meshed well together—to make for an entertaining session, although my note-taking hand cramped a lot more trying to keep up with Lewis.

She focused her presentation on work her group has done with direct-write assembly of ink filament. In the case of silver nanowires, this involves taking a colloidal mixture of 70 to 85% Ag nanoparticles and extruding it through a nozzle to “write” a structure. This technique enables what Lewis called “omnidirectional,” or 3-D, printing of microelectrodes.

In response to a question about the speed of this writing technique (on average 1 mm/second) she mentioned that her team is currently working to reduce manufacture time, particularly with multinozzle arrays.

Courtesy of the Messersmith Group

Courtesy of the Messersmith Group

Messersmith discussed materials his group has fabricated on the basis of the chemical composition of adhesive proteins that mussels use to stick to “any surface you throw at them.” Specifically, mussel adhesive proteins contain high concentrations of 3,4-dihydroxy-l-phenylalanine (DOPA). And it is the catechol group in this compound that is suspected to cause bonding to surfaces, although there’s a lot that’s still unknown about the mechanism.

One attendee asked whether barnacles bind to surfaces in the same way. Messersmith said that it isn’t through DOPA (which hasn’t been detected), but because barnacle protein is protected by a calcified shell, it’s also harder to study.

At the end of the session, Messersmith previewed some work his team has been doing with DOPA-based adhesives to more strongly attach transplanted islets to a diabetes patient’s liver. In addition, he mentioned using the sticky compounds surgically for fetal membrane wound closure.

Although most of the research presented during this session wasn’t new, I enjoyed listening to two well-known experts that I had never heard speak before talk in detail about their work. Did anybody else out there get to attend a good (or maybe it was bad?) presentation by a scientist you’ve always wanted to hear speak?

Author: Lauren Wolf

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