Three Georgetown University physics professors are collaborating to research colloidal gels, a specific type of gel that can be used in applications ranging from food science to 3D-printed organs.
The National Science Foundation (NSF) awarded a three-year, $691,996 grant to Daniel Blair, Emanuela Del Gado and Jeffrey Urbach, professors in the physics department, for their investigation of these gels.
A gel is a semi-solid that, while largely composed of fluid, is held together by a network of some solid. Colloidal gels differ from other gels in that the solid that gives them structure is a collection of small, bloblike particles, as opposed to another common classification of gels: polymer gels (like in contact lenses), which have long, repeating chains of a molecule acting as the solid structure. An everyday example of a colloidal gel is Jell-O, which is held together by blobs of powdered gelatin.
“Everybody is excited about colloidal gels, because if you want to print things, these materials can reconfigure easily,” Del Gado said in an interview with The Hoya. “When you need, you can reshape them into something different.”
Urbach highlighted colloidal gels’ utility for organ transplants. More than 100,000 people in the United States alone are waiting for organ donations.
“If you want to, say, 3D print an organ, there’s a number of different things that it needs to be able to do. To be able to control that is about being able to understand where you transition from flowing to something that’s kind of solid,” Urbach said in an interview with The Hoya.
Blair, Del Gado and Urbach aim to use the new NSF grant money to better understand how individual particle movement impacts the wider structure of the entire gel, which could vary properties such as stiffness, tensile strength and viscosity. Urbach said parts of their desired research comprises deep gaps in the scientific community’s knowledge.
“Some of this stuff really is wide open. We’re just not really sure what we’re gonna find,” Urbach told The Hoya.
Until recently, it was essentially impossible to measure the full extent of motion that particles within colloidal gels undergo. Last year, however, researchers at the University of Oxford discovered how to stain a particle such that the bulk of it is one color, but part of the particle that is off center is a different color.
This staining technique, which was led by former Oxford professor Roel Dullens, allows researchers to measure the rotation of the solid particles within the gel. Measuring the rotation of the particles within the gel is vital because particles unable to move laterally may still be able to rotate. This motion could potentially greatly impact the properties of the gel.
“We are very excited about the ability to combine experiments and simulations in this research, because basically, in the simulation, we have developed models to generate these structures, and then perform tests and understand how things change at the level of the single particle,” Del Gado said in an interview with The Hoya.
Del Gado’s lab will focus on the computer simulations, while Blair and Urbach will focus on the experimental side of the research. Urbach, Del Gado and Blair believe that their partnership, as well as the combination of simulation and experimentation in their research, will allow them to get to the heart of the issue.
“There is sort of one experimental stream and one computational stream, but they overlap continuously. The computational work will be continuously informed by and inform the measurements. We’ve had this type of collaboration over the years,” Urbach said in an interview with The Hoya.
According to Blair, this collaboration is particularly useful in scientific research.
“The ideas come from each person’s individual expertise and way of thinking that gets then tested and tried and thought about. It’s a very nice way of doing science,” Blair said in an interview with The Hoya.
The three researchers also said their labs will provide valuable training opportunities for student researchers at Georgetown.
“It’s an important part of why this is a good use of taxpayer money,” Urbach said. “Most of our student researchers will end up in industry in one way or another. It’s young researchers who are trained with federal grant support, who really drive the innovation in this country.”
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