3D-printed brain sensors may unlock personalized neural monitoring

Penn State

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The soft bioelectrodes use a honeycomb-inspired design that allows researchers to stretch them onto the specific geometry of a patient’s brain, without sacrificing structural strength or sensitivity to electrical and physiological signals.

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Credit: Provided by Tao Zhou

UNIVERSITY PARK, Pa. — Soft electrodes designed to perfectly match a person’s brain surface may help advance neural interfaces for neurodegenerative disease monitoring and treatment, according to a new study led by Penn State researchers. Neural interfaces are powered by tiny sensors capable of tracking biophysical signals, known as bioelectrodes. These sensors are usually made from stiff materials in a one-size-fits-all design that struggles to match the brain’s complex structure. The researchers have created a novel approach to 3D printing bioelectrodes that can stretch and morph to fit the minor differences that make every brain unique.

The team used software to simulate detailed brains based on MRI scans taken from 21 human patients, shaping a set of electrodes tailored for brains’ specific structures before 3D printing the electrodes and models of the brains. In a paper published in Advanced Materials, they reported that their electrodes better fit the structure of the brain than traditional designs, while remaining effective and biologically compatible, even in tests done in rats.

The folds in the human brain are created through a process known as gyrification, where the cortical sheet on the outer wall of the brain bunches up into ridges, known as gyri, and grooves, known as sulci. This helps cells across the brain communicate at high speeds, and allows for a relatively large organ to fit compactly in the skull — a spread-out adult brain would be around 2,000 square centimeters, or about the size of two large pizzas.

Although the major cortical folds are consistent across individuals, the precise layout of the brain’s gryi and sulci changes substantially from person to person, according to Tao Zhou, Wormley Family Early Career Professor, assistant professor of engineering science and mechanics and corresponding author on the paper. However, traditional bioelectrode designs don’t take this into account.

“Each person has a different brain structure, depending on their height, weight, age, sex and more,” said Zhou, who also holds an affiliation in biomedical engineering and the center for neural engineering at Penn State. “Despite this, we try to fit neural interfaces onto brains like they have identical structures. This motivated us to create electrodes that are tailored for each individual, based on the structure of their brain.”

The electrodes are built mainly from a water-rich material known as hydrogel to better match with the soft tissues and patient-specific geometry of a brain. Furthermore, the team used a novel honeycomb-inspired structure that offers flexibility and strength, while remaining cost-effective and quick to print, according to Zhou.

“The honeycomb structure helps us significantly reduce the stiffness of the electrodes, without sacrificing their mechanical strength,” Zhou said. “What’s more, the structure helps us reduce the overall material used during fabrication, reducing production time, cost and environmental impact.”

Production starts by taking an MRI scan of a patient's brain, which is used to conduct finite element analysis — a process that creates a detailed simulation of a person’s neural structure. This analysis is then rendered as a 3D model of the patient's brain, where the team uses computer software to tailor a bioelectrode specifically morphed to fit the ridges and grooves of the cerebral cortex.

After shaping, the team 3D prints the hydrogel electrode using direct ink printing, a technique that can create electrodes capable of monitoring and transmitting brain signals over a relatively small surface. For this study, the team 3D printed models of 21 different participant brains, applying their electrodes and physically measuring how accurately the electrodes could fit the brain surface. Zhou explained how traditional fabrication approaches require specialized facilities like clean rooms, making them incredibly expensive to customize — 3D printing allows the team to personalize and manufacture electrodes much faster, for a fraction of the price.

Compared to traditional approaches, the hydrogel-based electrodes follow the structure of the brain more precisely. Zhou said their approach produces electrodes that exhibit nearly perfect connectivity to electrical signals present in the brain. Additionally, because the stretchy gel is so malleable, it can be applied to the soft brain tissue without causing damage, compared to the stiff materials comprising other designs that could damage tissue.

According to Zhou, the softness of their electrodes enables closer and more stable contact with the brain, in turn facilitating higher-quality, more reliable monitoring. Moreover, bioelectrodes made with this approach don’t impact fluid transport around the brain, a critical aspect of brain function that many traditional electrodes disrupt.

“Personalizing the electrodes to the brain’s specific structure substantially improves their reliability,” Zhou said. “Because they conform to the brain better, the signal quality itself is significantly improved.”

To further study their electrodes, the team placed them onto the brains of rat models over a period of 28 days. The rats did not exhibit any immune response to the printed electrodes, a key consideration in biodevice development, Zhou said. Additionally, the electrodes did not exhibit performance degradation, while offering sensitive and accurate readings of the electric and physiological signals in the brain.

Zhou said he believes that this printing method could serve as a framework for the commercial-scale printing of bioelectrodes customized for specific patients. Although these systems are traditionally used for monitoring neural activity, the team plans to explore how personalized electrodes may contribute to neurological treatments.

“We are looking to further improve this technology to optimize the electrodes to monitor for specific diseases,” Zhou said. “In the future, we would really like to work with patients to see how this approach could support brain monitoring and disease treatment in clinical settings.”

Additional co-authors affiliated with Penn State include Nanyin Zhang, professor of biomedical engineering and Dorothy Foehr Huck and J. Lloyd Huck Chair in Brain Imaging; Sulin Zhang, professor of engineering science and mechanics and of biomedical engineering; engineering science and mechanics doctoral candidates Marzia Momin, Luyi Feng, Salahuddin Ahmed and Jiashu Ren; biomedical engineering doctoral candidates Xiaoai Chen, Hyunjin Lee and post-doctoral scholar Samuel R. Cramer; mechanical engineering doctoral candidate Xinyi Wang; Basma AlMahood, an undergraduate student studying physics at the time of research who is now a physics doctoral candidate at Michigan State University; and Li-Pang Huang, a research assistant.

This work was supported by the U.S. National Science Foundation and the National Institutes of Health.

At Penn State, researchers are solving real problems that impact the health, safety and quality of life of people across the commonwealth, the nation and around the world.    

For decades, federal support for research has fueled innovation that makes our country safer, our industries more competitive and our economy stronger. Recent federal funding cuts threaten this progress.  

Learn more about the implications of federal funding cuts to our future at Research or Regress.

  

Using 3D-printed models of several patients' brains, the team tested how well their electrodes could stretch to fit the individual cortical geometry – their electrodes can snugly fit atop the geometry of a patient’s brain with more precision than systems created with traditional methods.

Credit

Provided by Tao Zhou

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Journal

Advanced Materials

DOI

10.1002/adma.202516291 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

3D-Printable, Honeycomb-Inspired Tissue-Like Bioelectrodes for Patient-Specific Neural Interface

 

Study finds warmer streams may weaken river food webs

Northern Arizona University

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This graphic shows how increasing water temperatures shift the way microbes and aquatic insects use carbon. As water warms and leaves decompose, less of the leaves’ carbon is converted into usable biomass and more of their carbon is released as CO₂. 

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Credit: Victor Leshyk-Ecoss, NAU

Rising stream temperatures may be weakening the foundation of river food webs by altering how carbon moves through these watery ecosystems. 

In a new study published in the journal Ecosphere, researchers from Northern Arizona University found that when water temperatures increase, microbes and aquatic insects process fallen leaves, twigs and bark more rapidly, but a smaller fraction of that leaf litter supports their growth and a bigger fraction is released into the water and air as carbon dioxide.  

The findings point to a shift in how river ecosystems retain energy under warming conditions, with implications for plants and animals in rivers across the western United States. 

“Warming doesn’t just speed up biological processes in streams—it changes how efficiently organisms turn carbon into biomass, with more of it being lost as CO₂,” said Michael Zampini, a postdoctoral researcher at NAU and the lead author of the study. 

A ‘living laboratory’ to track carbon flow 

To examine how warming affects river processes, the NAU researchers built a controlled stream system at The Arboretum at Flagstaff, constructing 48 flow-through mini stream chambers inside a greenhouse. Using pond water, they manipulated the water temperature while maintaining natural light and water chemistry, simulating a range of stream conditions over two years. 

“This system let us manipulate temperature while keeping everything else as close to a real stream as possible, which is critical for understanding how these processes actually play out in nature,” said Zampini. 

Within this system, the team used tracers to follow carbon from leaf litter—the primary energy source in many forested rivers—into microbes and caddisflies. By labeling leaves with a rare form of carbon, they directly measured how much carbon was retained as biomass, how much of it was released into the water and air as CO₂ and how much was transferred to microbes and insects, allowing them to quantify how effectively organisms converted food into growth. 

Faster processing, lower retention in warming streams 

The researchers found that as temperatures increased, decomposition rates rose, but a larger share of carbon was lost as CO₂ rather than incorporated into biomass. Caddisflies showed a distinct thermal response, with low temperatures limiting their activity, intermediate temperatures maximizing their efficiency, and higher temperatures increasing their consumption without corresponding gains in biomass. Together, these patterns indicate that warming releases more carbon into the atmosphere and converts less carbon into biomass. 

“Even when consumption increases, the system becomes less efficient—more carbon goes to respiration and less to building the food web,” said Jane Marks, professor in the Department of Biological Sciences and the Center for Ecosystem Science and Society (Ecoss) at NAU. 

In rivers across the Southwest, where aquatic insects link leaf litter to animals higher on the food chain such as fish, this shift has broader implications. Declines in carbon use efficiency for microbes and aquatic insects mean a greater proportion of carbon entering rivers may be lost to the atmosphere, reducing energy available to support aquatic food webs.  

“When less carbon is retained in biomass, there is less energy available to support aquatic life, which can ripple through the food web and ultimately affect fisheries, water quality and ecosystem stability that people depend on,” Marks said. 

Other researchers involved in the study included University of Alabama professor Steven Thomas and Northern Arizona University researchers George Koch, Benjamin Koch, Paul Dijkstra and Victor Leshyk at Ecoss. The research was funded by the National Science Foundation (DEB-1120343). 

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The “living laboratory” constructed by researchers at Northern Arizona University. This controlled stream system at the Flagstaff Arboretum allowed scientists to manipulate water temperatures and directly observe how aquatic organisms responded. 

Credit

Victor Leshyk-Ecoss at NAU

Journal

Ecosphere

DOI

10.1002/ecs2.70585 

Method of Research

Experimental study

Article Title

Temperature accelerates decomposition and controlscarbon use efficiency for microbes and shreddingcaddisflies

Article Publication Date

18-Apr-2026

 

‘Tis the season: Sharing resources sustains ocean microbial biodiversity

University of Hawaii at Manoa

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A view of the rosette water sampler as it ascends toward the surface to collect samples. 

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Credit: Hawai'i Ocean Time-series

Oceanographers from the University of Hawai‘i at Mānoa discovered that microbial communities–from the sunlit surface to extreme depths–in the North Pacific Subtropical Gyre exhibit robust seasonal cycles. The study provides new insight into how high levels of biodiversity are maintained in the open ocean. 

“A long-standing question in biological oceanography, which we refer to as the “paradox of the plankton”, asks: How can open ocean species diversity be so vast and sustained, in a seemingly homogeneous environment like the open ocean?,” said Fuyan Li, lead author of the study and affiliate researcher in the Center for Microbial Oceanography: Research and Education in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST).

The blue, deep waters of the Pacific Ocean have extremely low nutrient concentrations compared to coastal areas that teem with visible life, such as kelp forests off California or coral reefs in Hawai‘i. 

“Theoretical ecology suggests that one way co-occurring species diversity can be maintained, is if shared resources, such as nutrients, are used at different times of year, thereby minimizing competition,” Li shared. “Though seasonal cycles are a fundamental property of many diverse ecosystems, seasonality in the tropics is less pronounced than in temperate or polar ocean habitats.”  

Tracking microbes through DNA

To determine whether microbial communities at Station ALOHA, a tropical, open ocean research station 60 miles north of O‘ahu, Hawai‘i, have seasonal cycles, Li and colleagues analyzed microbial DNA in samples collected monthly over eight years. The combination of frequent sampling over a long time period, and high-resolution species identification, allowed the researchers to make these new and unprecedented open ocean observations. 

They found that more than 60% of the microbial groups they tracked exhibited seasonal cycling. While these seasonal cycles diminished at depths below 150 meters, surprisingly, they remained measurable in some deep-sea microbial species at depths of nearly two and a half miles. 

“Notably, very closely related species or subspecies “bloomed” at different times of the year, similar to seasonal patterns observed in some terrestrial plants and animals,” Li said. “Taking turns with respect to nutrient use throughout the year seems to be a key ecological strategy for microbial communities to maintain their diversity.”

By sustaining their populations throughout the year, microbial communities consistently supply organic matter and energy to organisms higher in the food web, for example larval fish. In this way, microbes ensure the stability of the marine food web and productivity in waters across the Pacific Ocean.

 

Researchers deployed a rosette water sampler to colllect water from the surface to the deepest depths at Station ALOHA, 60 miles north of O‘ahu, Hawai‘i.

Credit

Fuyan Li, University of Hawai‘i at Mānoa

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Journal

The ISME Journal

DOI

10.1093/ismejo/wrag062 

Method of Research

Observational study

Subject of Research

Cells

Article Title

Seasonality drives temporal niche partitioning of pelagic prokaryotes

Article Publication Date

9-Apr-2026

 

MIT study shows youth may increase vulnerability to a carcinogen found in contaminated water and some drugs

The new study suggests that the chemical NDMA is much more likely to cause cancerous mutations after exposure early in life.

Massachusetts Institute of Technology

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CAMBRIDGE, MA -- A new study from MIT suggests that a carcinogen that has been found in medications and in drinking water contaminated by chemical plants may have a much more severe impact on children than adults.

In a study of mice, the researchers found that juveniles exposed to drinking water containing this compound, known as NDMA, showed dramatically higher rates of DNA damage and cancer than adults.

The findings may help to explain an epidemiological association between childhood cancer and prenatal exposure to NDMA in people living near a contaminated site in Wilmington, Massachusetts, the researchers say. The study also suggests that it is critical to evaluate the impact of potential carcinogens across all ages.

“We really hope that groups that do safety testing will change their paradigm and start looking at young animals, so that we can catch potential carcinogens before people are exposed,” says Bevin Engelward, an MIT professor of biological engineering. “As a solution to cancer, cancer prevention is clearly much better than cancer treatment, so we hope we can spot dangerous chemicals before people are exposed, and therefore prevent extensive cancer risk.”

MIT postdoc Lindsay Volk is the lead author of the paper. Engelward is the senior author of the study, which appears in Nature Communications.

From DNA damage to cancer

NDMA (N-Nitrosodimethylamine) can be generated as a byproduct of many industrial chemical processes, and it is also found in cigarette smoke and processed meats. In recent years, NDMA has been detected in some formulations of the drugs valsartan, ranitidine, and metformin. It was also found in drinking water in Wilmington, Massachusetts, in the 1990s, as a result of contamination from the Olin Chemical site.

In 2021, a study from the Massachusetts Department of Health suggested a link between that water contamination and an elevated incidence of childhood cancer in Wilmington. Between 1990 and 2000, 22 Wilmington children were diagnosed with cancer. The contaminated wells were closed in 2003.

Also in 2021, Engelward and others at MIT published a study on the mechanism of how NDMA can lead to cancer. In the new Nature Communications paper, Engelward and her colleagues set out to see if they could determine why the compound appears to affect children more than adults.

Most studies that evaluate potential carcinogens are performed in mice that are at least 4 to 6 weeks old, and often older. For this study, the researchers studied two groups of mice — one 3 weeks old (juvenile), and one 6 months old (adult). Each group was given drinking water with low levels of NDMA, about five parts per million, for two weeks.

Inside the body, NDMA is metabolized by a liver enzyme called CYP2E1. This produces toxic metabolites that can damage DNA by adding a small chemical group known as a methyl group to DNA bases, creating lesions known as adducts.

When the researchers examined the livers of the mice, they found that juveniles and adults showed similar levels of DNA adducts. However, there were dramatic differences in what happened after that initial damage. In juvenile mice, DNA adducts led to significant accumulation of double-stranded DNA breaks, which occur when cells try to repair adducts. These breaks produce mutations that eventually lead to the development of liver cancer.

In the adult mice, the researchers saw essentially no double-stranded breaks and significantly fewer mutations compared to juveniles. Furthermore, the livers did not develop severe pathology, including tumors, even though they experienced the same initial level of DNA adducts.

“The initial structural changes to the DNA had very different consequences depending on age,” Engelward says. “The double-stranded breaks were exclusively observed in the young.”

Further experiments revealed that these differences stem from differences in the rates of cell proliferation. Cells in the juvenile liver divide rapidly, giving them more opportunity to turn DNA adducts into mutations, while cells of the adult liver rarely divide.

“This really emphasizes the overall problem that we’re trying to highlight in the paper,” Volk says. “With toxicological studies, oftentimes the standard is to use fully grown mice. At that point, they’re already slowing down cell division, so if we are testing the harmful effects of NDMA in adult mice, then we’re completely missing how vulnerable particular groups are, such as younger animals.”

While most of these effects were seen in the liver, because that is where NDMA is metabolized, a few of the mice developed other types of cancer, including lung cancer and lymphoma.

Adult risk is not zero

For most of these studies, the researchers used mice that had two of their DNA repair systems knocked out. This speeds up the mutation process, allowing the researchers to see the effects of NDMA exposure more easily, without needing to study a large population of mice.

However, a small study in mice with normal DNA repair showed that juveniles experienced NDMA-induced double-strand breaks, regenerative proliferation, and large-scale mutations that were completely absent in adults. This occurs because the fast-growing juveniles possess highly active DNA replication machinery that encounters the DNA adducts before the cell has time to repair them.

The researchers also found that if they treated adult mice with thyroid hormone, which stimulates proliferation of liver cells, those cells began accumulating mutations as quickly as the juvenile liver cells. Previous work done in the Engelward laboratory has shown that inflammation can also stimulate cell proliferation-driven vulnerability to DNA damage, so the findings of this study suggest that anything that causes liver inflammation could make the adult liver more vulnerable to damage caused by agents such as NDMA.

“We certainly don’t want to say that adults are completely resistant to NDMA,” Volk says. “Everything impacts your susceptibility to a carcinogen, whether that’s your genetics, your age, your diet, and so forth. In adults, if they have a viral infection, or a high fat diet, or chronic binge alcohol drinking, this can impact proliferation within the liver and potentially make them susceptible to NDMA.”

The researchers are now investigating how a high-fat diet might influence cancer development in mice that also have exposure to NDMA.

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This collaborative effort across several MIT labs was funded by the National Institutes of Environmental and Health Sciences (NIEHS) Superfund Research Program, a NIEHS Core Center Grant, a National Institutes of Health Training Grant, and the Anonymous Fund for Climate Action.

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Journal

Nature Communications

DOI

10.1038/s41467-026-71753-w 

Subject of Research

Animals

Article Title

Early life exposure to N-nitrosamine drives genotoxicity, mutagenesis, and tumorigenesis in DNA repair-deficient mice

Article Publication Date

14-Apr-2026