To measure the force of TBIs, this VCU lab builds a better brain

By Madeline Reinsel

The medical consequences of traumatic brain injuries are well-studied and affect millions of Americans every year. But one of the brain's complexities is less explored: how much force from a car crash, explosion or other injury makes its way into the brain itself.

To find out, a Virginia Commonwealth University College of Engineering lab led by associate professor Ravi Hadimani, Ph.D., has turned to making its own realistic brain replicas, or "phantoms," to simulate the impact.

"We started developing brain phantoms to measure or to evaluate stress and strain in the brain due to concussion, g-forces or traumatic brain injury," Hadimani said. "And to do that, we have to replicate the brain structure."

So, the researchers have started small, looking to one of humanity's most studied lab critters - the rat.

Hadimani's lab specializes in using 3D printing to design realistic models that mimic the physical properties of brains - both human and otherwise. The lab previously developed human brain models to study the effects of transcranial magnetic stimulation, a treatment for various psychiatric disorders.

The lab's latest work, highlighted in a recent publication, has strong ties to one of Hadimani's team members - who actually is still a high school student.

"I became interested in the physical effects of brain trauma and noticed a research gap," said Sanaya Bothra, a senior at nearby Maggie L. Walker Governor's School, who has worked in Hadimani's lab since 2023 - and who is the first author on the recent article. "Our lab had brain phantoms for electromagnetic testing, but none capable of measuring mechanical injury."

To fill that gap, the researchers are rebuilding their brains from scratch. While the lab's earlier models replicated the magnetic and electrical properties of the brain, the new models simulate the brain's viscosity - basically, a measure of how thick or thin a liquid is.

"Different regions of the brain can have different elastic properties," Hadimani said. "And we make sure that our brain phantoms have accurate viscoelastic properties representing the real brain."

First, the researchers used publicly available MRI and CT scans to physically replicate different regions of a rat brain with an adaptable hydrogel material. Hydrogels are made of polymers, which are long chains of repeating molecules, and can be found in many common beauty products. But they may be most recognizable in a popular dessert form: Jell-O, which is made of naturally occurring gelatin polymers.

"The hydrogel is a polymer that's swelled with water," said Wesley Lohr, a Ph.D. student in Hadimani's lab who oversees the 3D printing process. "The polymer basically creates a network, sort of like a sponge, and it soaks up the water."

The researchers cast their hydrogel brains from sets of 3D-printed plastic shells, much like how your grandmother may have poured liquid Jell-O into an aluminum mold to set. They then slowly assembled the brains through a complicated freeze-thaw process, and embedded them with sensors that convert the physical pressure from a mock traumatic brain injury into electricity. During testing, they can read that voltage to find out how much force the brain experienced.

Using rat brains as the model has practical value, Hadimani said - and his lab's work creating brain models doesn't involve lab animals.

"It's expensive, and you need quite a lot of new material, to create a human brain," Hadimani said. "So, rat brains are quicker to make, and also a lot of people are interested in them."

The rat brains, he said, could potentially be used by other researchers looking to move away from using live lab rats in their experiments.

While Hadimani's team has been testing its sensors in the lab, the next test is a little less earthbound. The lab has partnered with Ram Rocketry to launch a rat brain model, embedded with an accelerometer, in a rocket in a national competition in March. That should help researchers measure the effects of g-forces on the brains, which are patented under the lab's startup, Realistic Anatomical Model (RAM) Phantoms.

The researchers also are thinking big - bigger than a rat, at least - for their next project: creating a hydrogel brain to model traumatic brain injuries in humans.