U.S. Naval Research Laboratory Develops Anatomically Accurate Rat Brain Phantom for Traumatic Brain Injury Research

WASHINGTON, D.C.   –   Researchers at the U.S. Naval Research Laboratory (NRL), in collaboration with Virginia Commonwealth University (VCU), have developed the first anatomically accurate rat brain phantom capable of measuring traumatic brain injury (TBI) impacts in real time.

The breakthrough model replicates the mechanical properties of brain tissue while embedding a piezoelectric sensor that converts impact forces directly into measurable electrical signals, offering unprecedented insight into how blast waves and impacts propagate through the brain.

This innovation builds on a multi-year research partnership between NRL scientist Margo Staruch, Ph.D., and VCU Professor Ravi Hadimani, who temporarily came to work at NRL through the Office of Naval Research (ONR) Summer Faculty Fellowship Program. Their collaboration, which continued after Professor Hadimani returned to VCU, combines expertise in biomagnetics, hydrogels, and sensing technologies to create a realistic, tunable platform for studying injury mechanics without the limitations of in-vivo testing.

A Realistic Model for Understanding Brain Injury

The new phantom uses a custom hydrogel, made from polyvinyl alcohol (PVA) and phytagel, that matches the viscoelastic response of living brain tissue. Traditional models often rely on rigid polymers or simplified surrogates, but NRL’s composite material reproduces both the softness and the dynamic wave behavior characteristic of real brain matter.

“We wanted to build a phantom that doesn’t just look like a brain, but behaves like one,” Hadimani said. “Most surrogates are either too simple in structure or don’t capture the true mechanical properties of gray and white matter. For the first time, we’ve been able to mimic the rat brain’s layers, from skull and cerebrospinal fluid to gray and white matter, while also matching their viscoelastic behavior.”

To measure forces inside the structure, the team embedded a thin film of polyvinylidene fluoride (PVDF), a piezoelectric polymer that generates voltage when stressed. This enables precise, real-time tracking of strain-rate and impact signatures.

“This model lets us see what is actually happening inside the brain during an impact,” Staruch said. “By embedding a piezoelectric sensor within a material that behaves like real brain tissue, we can track how forces move, concentrate, or dissipate, which had been incredibly difficult to measure in real time until now.”

Reliable, Scalable, and Ethically Grounded

Testing conducted with both drop-tests and mechanical compression systems confirmed a linear relationship between impact severity and strain rate, validating the phantom’s sensitivity across low-force and high-force events. This is especially important for understanding mild TBI and blast exposure, where forces may be subtle but still lead to long-term neurological effects.

The team also identified realistic failure modes, such as microcracks forming within the surrogate skull, which helped interpret anomalies in the data and demonstrate the model’s realistic structural response.

“Having a reliable linear response means we can accurately correlate voltage output to impact severity,” Staruch said.

Because the phantom is fully synthetic and reproducible, it eliminates the ethical concerns and variability associated with animal testing while enabling controlled, repeatable experiments.

Potential Applications for Warfighter Protection

The model offers a foundation for examining how blast waves, overpressure, and repeated low-level exposures translate into mechanical strain within the brain, key information for understanding the root causes of TBI.

By scaling the model to human dimensions, researchers could strategically place sensors throughout the brain to test different impact directions and protective technologies.

“This tool gives us a clearer picture of where forces concentrate and how different impact directions affect the brain,” Staruch said. “That information can directly inform the design of improved helmets and protective gear, leading to better protection for warfighters and will also contribute to better diagnostic and treatment pathways for TBI.”

Future efforts may incorporate repeated-impact studies, directional blast-wave data, and integration with neural network models to explore the connection between mechanical strain and neurological changes.

Collaboration and Continued Research

This effort builds on earlier NRL research in piezoelectrics and materials science, as well as prior hydrogel-based brain phantom work from VCU.

“The motivation for this work came directly from the ongoing TBI modeling efforts at NRL,” Hadimani said. “Through the ONR Summer Faculty Fellowship, I saw how our material science research at VCU could merge naturally with NRL’s expertise in sensing and strain measurement. That partnership allowed us to create a far more accurate and personalized phantom than what existed before.”

 The ONR Summer Faculty Fellowship Program played a key role in bringing together complementary expertise that led to this new advancement in neurotrauma research.

About the U.S. Naval Research Laboratory

NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL, located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.

NRL offers several mechanisms for collaborating with the broader scientific community, within and outside of the Federal government. These include Cooperative Research and Development Agreements (CRADAs), LP-CRADAs, Educational Partnership Agreements, agreements under the authority of 10 USC 4892, licensing agreements, FAR contracts, and other applicable agreements.

For more information, contact NRL Corporate Communications at NRLPAO@us.navy.mil.