At the University of Virginia, a materials engineer is turning water-rich polymers into something that behaves like living human tissue — and the National Institutes of Health has invested $2.1 million in the effort. Steven Caliari's work on hydrogels sits at a quiet but consequential frontier: the possibility that the animals long used to test drugs and study disease might one day be replaced by engineered tissue that more faithfully reflects the human body. It is a shift not merely of method but of philosophy — toward a science that asks whether we can understand life by building it, rather
UVA researcher secures $2.1M NIH grant to develop lab tissue models reducing animal testing
You need simplified systems to say which factor caused which change
Mark
Why does it matter that these are hydrogels specifically, rather than just any artificial tissue?
Mimi
Because tissues aren't static. They're soft and hard at the same time, and they change over time. A hydrogel can be engineered to capture that complexity in a way that lets you isolate one variable—say, stiffness—and watch how cells respond to just that change. You can't do that in an animal.
Mark
So you're saying animal models are actually too complicated for what you're trying to learn?
Mimi
Exactly. An animal can show you that something happens, but it can't easily show you why. There are too many variables changing at once. A simplified system lets you say: this mechanical property caused this cellular response.
Mark
The grant focuses on fibroblasts and scarring. Why that particular cell type?
Mimi
Fibroblasts are the cells that heal wounds, which sounds good until they don't stop. When they become overactive, they create fibrosis—excessive scar tissue that stiffens organs and makes them fail. It's a problem in the lungs, the kidneys, the heart. Understanding how to control them could treat multiple diseases at once.
Mark
You mentioned 3D bioprinting. How does that change what you can study?
Mimi
It lets you build tissue architecture that actually resembles human organs, not just flat sheets of cells. You can create the layering, the structure, the spatial relationships that exist in a real tissue. That's closer to what a drug would actually encounter in a patient.
Mark
What does it mean that this is his second MIRA grant?
Mimi
It means the NIH is betting on him long-term, not just on one project. The first grant was about potential. The second is about validation—they're saying his vision matters, and they want to fund where it goes next.
O Pulso
- Animal testing remains a cornerstone of biomedical research, yet its limitations — species differences, ethical costs, and imprecision — have long pressed scientists to find a better way.
- Caliari's hydrogels can mimic the mechanical complexity of real tissue, giving researchers a way to watch how cells behave under conditions that closely resemble the human body.
- A $2.1M NIH MIRA grant — his second, a rare institutional vote of confidence — now funds three interlocking research threads: better hydrogels, fibroblast-immune cell communication, and 3D bioprinted organ architecture.
- Fibrosis, the runaway scarring that stiffens lungs, kidneys, and hearts, sits at the center of the disease work, offering a high-stakes proving ground for what these models can reveal.
- The team is scaling toward high-throughput formats that could allow patient-specific therapeutic testing in the lab — moving drug development closer to the individual and further from the animal.
At the University of Virginia, a materials engineer is turning water-rich polymers into something that behaves like living human tissue — and the National Institutes of Health has invested $2.1 million in the effort. Steven Caliari's work on hydrogels sits at a quiet but consequential frontier: the possibility that the animals long used to test drugs and study disease might one day be replaced by engineered tissue that more faithfully reflects the human body. It is a shift not merely of method but of philosophy — toward a science that asks whether we can understand life by building it, rather than by borrowing it.
Steven Caliari works in a lab at the University of Virginia where water-rich polymers are coaxed into behaving like human tissue. This week, the National Institutes of Health awarded him $2.1 million over five years to continue that work — building artificial tissues that could reduce, and perhaps one day replace, the animals currently used to test drugs and study disease.
Caliari's materials, called hydrogels, are engineered to reproduce the physical properties of living tissue: its stiffness, softness, and elasticity. Getting those mechanics right matters because cells respond to their physical environment, and understanding those responses has historically required animal models. His lab offers a different path — simplified, controllable systems where cause and effect can be isolated. "You need these reductionist systems to do that," he said.
The grant comes through the NIH's Maximizing Investigators' Research Award program, which funds a researcher's entire vision rather than a single project. It is Caliari's second such award — a distinction his department chair called a genuine validation of the work's importance.
The funding supports three research directions: refining hydrogels to better capture tissue complexity; studying how fibroblasts and immune cells communicate during scarring, and how tissue mechanics shape those signals; and combining hydrogels with light-based 3D bioprinting to recreate the architecture of real human organs. Fibrosis — the excessive scarring that stiffens lungs, kidneys, and hearts — is a central focus, offering a clinically urgent test case.
UVA's concentration of expertise in hydrogel design, fibrotic disease, and alternatives to animal testing makes the collaboration possible. Graduate researchers and faculty partners Dan Abebayehu and Chris Highley are part of the effort. The team is also developing high-throughput formats to test many experimental conditions at once, with an eye toward patient-specific therapeutic evaluation. If it works, the result would be more than a better research tool — it would represent a fundamental shift in how biomedical science understands and treats disease.
Steven Caliari sits in a lab at the University of Virginia, surrounded by the tools of a particular kind of alchemy: the transformation of water-rich polymers into something that behaves like human tissue. This week, the National Institutes of Health awarded him $2.1 million over five years to keep doing exactly that—to build artificial tissues that could one day replace the animals now used to test drugs and understand disease.
Caliari is an associate professor in chemical and biomedical engineering, and his lab has spent years developing hydrogels, materials engineered to mimic the physical properties of living tissue. The work sits at an intersection that matters: tissues are neither purely solid nor purely liquid, and they change over time in ways that are fiendishly difficult to recreate in a lab. But if you can get the mechanics right—the stiffness, the softness, the elasticity—you can watch how cells respond without needing to run experiments on animals. "From an engineering perspective, we want to say, 'This factor led to this change in cell behavior,'" Caliari explained. "You need these simplified reductionist systems to do that."
The grant, awarded through the NIH's Maximizing Investigators' Research Award program, is notable for what it funds and how. Rather than supporting a single discrete project, a MIRA backs a researcher's entire program, providing steady money and the freedom to chase ideas within a broader vision. This is Caliari's second one—the first came as he was building his lab—and the second is, in the words of his department chair, a validation. "To get one is impressive," said Ayman Karim, the Olsen Professor of chemical engineering. "The second is truly a validation of the importance of Steven's research."
The new funding will pursue three interconnected lines of work. The first will engineer hydrogels that more faithfully reproduce the mechanical complexity of actual human tissues. The second will examine how fibroblasts—connective tissue cells crucial to wound healing—communicate with immune cells during scarring, and how the mechanical properties of tissue shape those conversations. Fibroblasts, when overactive, produce excessive scar tissue through a process called fibrosis, which stiffens organs and robs them of function. It's a problem in the lungs, kidneys, heart, and elsewhere. The third research theme will marry the hydrogels with advanced light-based 3D bioprinting to create tissue models that more closely resemble the actual architecture of human organs.
What makes this work possible at UVA, Caliari said, is the density of expertise already present—people working in hydrogel design, fibrotic disease, cell interactions, and alternatives to animal testing. The project will fund graduate positions and includes collaborations with biomedical engineering faculty members Dan Abebayehu and Chris Highley. "There are a lot of people working in this general area, and they are trying to get away from animal models to instead develop in vitro models that more accurately capture human disease," Caliari said. "My work fits in nicely with that."
If the research succeeds, it could produce something like a toolkit—a set of methods for building realistic laboratory models of human tissues that researchers could use to test therapies in conditions that more closely reflect individual patients. The team is also working to scale the technology using high-throughput formats, which would allow many experimental conditions to be tested simultaneously. The goal is not just to improve research but to reduce the animal burden. "If we design these materials in the right way, we can study therapeutic approaches in a patient-specific way," Caliari said. That shift—from testing drugs on animals to testing them on engineered human tissues tailored to individual patients—would represent a fundamental change in how biomedical science works.
Citações Notáveis
From an engineering perspective, we want to say, 'This factor led to this change in cell behavior.' You need these simplified reductionist systems to do that.— Steven Caliari, associate professor of chemical and biomedical engineering at UVA
To get one is impressive. The second is truly a validation of the importance of Steven's research and what the NIH thinks of its benefit to society.— Ayman Karim, Olsen Professor and chemical engineering chair at UVA
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