Kirkpatrick

Scientists develop hydrogel platform that mimics human tissue

Susan Glairon — Thu, 12 Mar 2026 22:55:27 +0000

Scientists develop hydrogel platform that mimics human tissue Susan Glairon Thu, 03/12/2026 - 16:55

Susan Glairon

Bone marrow-derived mesenchymal stromal cells (purple) interact with a hydrogel matrix (green). In viscoelastic materials, the cells can spread and reshape the matrix.

For decades, lab-grown cells have been studied in materials that don’t reflect the softness and flexibility of human tissue.

Bruce Kirkpatrick

Researchers at the University of Colorado Boulder have developed a water-rich, Jell-O-like material that more closely mimics how real tissues move, stretch and relax and whose liquid or solid state can be precisely controlled by light.

The work was recently published in the journal Matter and was directed by Distinguished Professor Kristi Anseth.

These new hydrogels will help scientists understand how mechanical cues from tissues affect cells, said Bruce Kirkpatrick, (PhDBioEngr'25), the paper’s first author and a third-year medical student. These insights could help improve our understanding of disease and how cells respond to drugs. It could also shed light on cell development—how stem cells mature into specialized cell types.

“The convention of growing cells on plastic for drug testing is problematic because plastic is stiff, while human tissue is flexible,” Kirkpatrick said. “Unless you're studying bone or other cells adapted to rigid environments, it’s not an appropriate mechanical setting for studying how cells respond to drugs.”

Kirkpatrick added that a key advantage of the hydrogel-based cell culture platform is its three-dimensional structure, which better reflects the environment cells experience in the body.

“The material we developed will help researchers better understand how mechanical environments influence cell behavior, not just the biochemical cues cells receive through surrounding liquid and nearby cells,” he said.

Shaped by light

Lea Hibbard

Most hydrogels form spontaneously when two liquids are mixed, but these gels provide less control and precision than the newly developed materials, Kirkpatrick said. In addition, researchers traditionally have shaped hydrogels using extrusion printing, a process similar to squeezing Play-Doh through a tube.

Instead, Kirkpatrick and the research team combined the new hydrogel’s dynamic properties with photopolymerization, using light to transform liquids into solids and encapsulate cells during three-dimensional printing. The new approach is faster and provides precise control over shape and material properties, Kirkpatrick said.

“With photopolymerization, we can control exactly how much light is applied, where it goes and when the hydrogel forms,” Kirkpatrick added. “The amount of light determines how much the material gels and its resulting mechanical properties. It gives researchers control over the shape, timing of cell encapsulation and spatial variation in properties.”

For example, if cells are encapsulated in a droplet and one side is exposed to light for only a few seconds while the other receives a longer or stronger dose, researchers can study what happens at the boundary between those regions, observing how cells migrate between them and how differences in mechanical properties influence their behavior.

Abhishek Dhand

The researchers also studied intestinal organoids—tiny lab-grown versions of the intestine—to see how they behaved in different environments. In the body, these cells exist in a soft, viscoelastic environment, where tissues stretch or deform under stress.

When the team placed the organoids in a hydrogel with similar properties, the cells took on natural shapes and expressed the right proteins. In other words, they behaved like they do inside the body.

“These findings suggest that viscoelasticity is essential for proper cell function and organization,” Kirkpatrick said.

Next steps

The researchers’ long-term goal is to use three-dimensional printing to produce large, cell-laden arrays of the new material for drug testing or disease modeling. This approach allows them to quickly create identical samples with high quality control and study how cells respond to gene mutations—such as removing a disease-linked gene—or to varying drug concentrations in the hydrogel environment.

The material could also help scientists study fundamental processes, such as how embryos organize cells to form correctly shaped organs, and investigate diseases like fibrosis, in which the body overproduces scar tissue in response to injury or chronic inflammation.

Co-first authors Abhishek Dhand, (PhDBioMedEngr’25), and PhD student Lea Hibbard (ChemBioEngr’24) contributed equally to this study. 91��ý faculty involved in the project included Professor Jason Burdick, Distinguished Professor Christopher Bowman and Professor Tim White.

A new light-controlled hydrogel developed at 91��ý mimics the movement and flexibility of real tissue, giving scientists a more realistic way to study cells and disease.

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Bruce Kirkpatrick honored with Outstanding Dissertation Award

Susan Glairon — Wed, 26 Nov 2025 20:16:06 +0000

Bruce Kirkpatrick honored with Outstanding Dissertation Award Susan Glairon Wed, 11/26/2025 - 13:16

Susan Glairon

Bruce Kirkpatrick

PhD, Biological Engineering, 2025

Dissertation Name

Photochemical Control of Hydrogel Network Topology: Fundamentals to Cellular Applications

Defended

July, 29, 2025

Associated lab

Anseth Group

Current position

Third-year medical student at the University of Colorado Anschutz Medical Campus and Denver Health

College of Engineering and Applied Science Outstanding Dissertation Award

This award recognizes the best dissertation (excellence of research, topical importance and presentation in the written dissertation) among students completing PhD degree requirements during a calendar year.

Why did you choose 91��ý for your graduate studies?

I came to CU in 2013 for my undergraduate degree in chemical and biological engineering (ChBE), and I really enjoyed it. After earning my BS in 2017, I applied to MD-PhD programs and was accepted at CU to continue into medical and graduate school. I was thrilled to return to ChBE as a graduate student because I knew how strong the biomedical research program was, especially with Distinguished Professor Kristi Anseth in the department. Having the chance to work with her and other faculty like Distinguished Professor Chris Bowman, Professor Jason Burdick and Professor Tim White offered the experiential learning in materials science and bioengineering that I hoped for as a budding physician-scientist. (Not to mention that it is great to live in Colorado! I’d be glad to never leave.)

Hydrogels serve as tiny scaffolds for creating precise patterns or gradients in stiffness or biochemical cues—illustrated here by a Mona Lisa narrower than a human hair—allowing fine control over the environment cells experience.

What does receiving this award mean to you?

It’s a huge honor to be selected by my mentors, department, and college.This award affirms that the years I’ve invested in both science and the community are valued. I’ve been part of the ChBE program for 12 years, and I’m grateful to have had the chance to do work worthy of this recognition. I owe a great deal to Dr. Anseth for her guidance and to my collaborators and mentees for giving so much of their time to bring our projects to fruition. I feel especially grateful to have grown my work in such a supportive and collaborative environment.

Tell me about your dissertation research.

Broadly, my research focuses on developing jello-like polymeric materials called hydrogels. I use light to build, break and rearrange the tiny chemical connections within them, which lets us control properties like stiffness, degradation, relaxation, and cell behavior with precise timing and location. This helps us create more tunable, lifelike environments for studying biology and developing future medical therapies.

Why does this research topic interest you?

This field naturally combines my interests in photochemistry, dynamic chemistry, and polymers with biophysics and materials science. Hydrogels are programmable, biologically relevant platforms, so the work is both scientifically rich and clinically useful.

What applications could this research have in the future?

This research supports technologies that enable long-acting or precisely timed drug and vaccine delivery, as well as protective hydrogels that shield donor cells from the immune system and improve their survival after transplantation. These materials can also be used to create acellular devices such as contact lenses, wound dressings, and tissue adhesives along with more realistic tissue models that give researchers better platforms for studying disease and testing new treatments.

Why do you think your dissertation resonated with the award committee?

By adjusting the properties of a surrounding hydrogel, Kirkpatrick could dramatically alter how 3D- embedded human cells stretch, spread and connect, revealing how their environment influences their behavior.

I think the committee appreciated the range of questions my dissertation addressed and how the work connected chemistry, materials science and biology in a coherent way. The projects included new approaches for designing photoresponsive hydrogels, studies of mechanobiology, and tissue engineering applications, with contributions that spanned departments, colleges, and campuses across CU. I think the committee also recognized how deeply collaborative the work was. Rather than solving a single problem, my thesis points toward a variety of future applications, so its impact comes from its breadth and the way it supports a wide range of community efforts.

Who was particularly influential to your work?

Dr. Anseth was the most influential figure in my scientific training. Her intellectual brilliance, generosity with her time, and ability to connect fundamental chemistry with meaningful biological questions have shaped the way I think about research. I’ve also learned a tremendous amount from her former trainees, many of whom now lead their own groups. I was especially inspired by Professor Cole DeForest, Associate Professor Mark Tibbitt, Professor Jason Burdick, Professor April Kloxin, and Tobin Brown’s work, to name a few. My amazing collaborators and mentees were essential to the success of every project and working alongside them is what made the science rewarding.

What’s next?

I plan to apply for residency in radiation oncology. I’m excited to work as a physician-scientist with interests in materials science and photochemistry, and my goal is to build a career that bridges the clinical care of cancer patients with research on biomaterials, imaging and analysis tools, and light-based technologies. I ultimately hope to contribute to new treatment strategies that are more tolerable, precise, and effective.

Chemical and Biological Engineering PhD Student Bruce Kirkpatrick was honored with the 2025 Outstanding Dissertation Award. His hydrogel research supports technologies that enable 3D cell culture for tissue engineering and disease modeling, as well as acellular biomaterials for applications like controlled release of drugs or vaccines.

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