In the course of military history, functional wearables and wearable devices have played a central role in military operations, providing both protection to troops and enhancing the capabilities of soldiers. From the development of forged plate armor in the middle ages, which replaced far heavier chain mail while providing better shielding, to the introduction of portable compasses in the 19th century, which transformed a soldier’s navigational capabilities, innovation in defense wearables has long been driven by a need to improve comfort and performance. The same is true today, as we advance into a new era of intelligent technologies, sensors and connectivity.This shift towards increasingly sophisticated, intelligent wearables in the defense sector is enabled by cutting-edge fabrication methods, such as <a href="https://www.voltera.io/products/nova?utm_campaign=Wevolver&amp;utm_source=website&amp;utm_medium=wearable-combat-devices&amp;utm_content=nova">Voltera’s NOVA</a> solution for printing electronics. This technology is proving to be key in the development of next-generation wearables that offer improved, adaptable comfort, continuous health monitoring, and discreet, real-time communication to soldiers in the field. In this article, we will be looking at why the NOVA platform is particularly well suited to wearable defense applications and examine three key application areas where the technology is revolutionizing military wearables. <h2><iframe src="https://www.youtube.com/embed/zsniZR1if1s?&amp;wmode=opaque&amp;rel=0" frameborder="0" style="width:640px;height:450px">   </iframe>Voltera’s NOVA, a platform for innovation</h2>Canadian company Voltera was founded in 2013 with the aim of making electronics development more accessible, agile, and versatile. Its NOVA platform, first released in 2022, is the embodiment of this goal, offering users a benchtop materials dispensing system capable of rapidly printing screen printable inks (1,000-1,000,000 cP) onto a wide variety of substrates, including rigid, flexible, stretchable, and novel materials. The platform can print functional electronics and sensors—including multilayer circuits—without the need for tooling, making it a valuable tool for electronics prototyping and development, materials testing, and manufacturing custom or low-volume devices. In the context of defense, the benefits of being able to rapidly iterate circuit designs for wearable devices and to make on-the-fly changes for improved functionality can’t be overstated, particularly for devices that have the potential to be life saving in the field. Another key advantage of Voltera’s NOVA platform for end-users in the defense sector is that it simplifies supply chains. With its modest footprint and intuitive user interface, NOVA can be used in-house. This means that wearable devices can be developed securely and near the point of need. For an industry like defense, where having a competitive technological advantage can mean the difference between a successful mission and a critical failure, NOVA therefore provides a vital capability.Now, without further ado, let’s look at some of the application areas where Voltera’s NOVA platform is unlocking new opportunities for mission-specific wearable electronics.<h2>Wearable heaters for enhanced thermal management</h2>One area where electronics printing can improve a soldier’s comfort and performance is thermal management. Adequate thermal management is essential for troops that are deployed in cold or harsh environments, helping to protect them from temperature-related injuries like frostbite and hypothermia, while also ensuring optimal physical and cognitive performance. Though the defense sector has seen vast improvements in this area in the last century—such as the development of lightweight, highly insulating fabrics—there is a continual push for more innovation in thermal management, with a particular focus on wearable heaters. With the ability to print conductive traces onto wearable materials, including tight-knit cotton, nylon, and Kevlar, Voltera’s NOVA platform is well positioned to drive the developments of wearable heating elements with minimal weight addition and without compromising the flexibility of the gear. In fact, the technology has already been used to such ends.In one use case, Voltera demonstrated how to <a href="https://www.voltera.io/use-cases/white-papers/printing-silver-conductive-ink-cotton-fabric?utm_campaign=Wevolver&amp;utm_source=website&amp;utm_medium=wearable-combat-devices&amp;utm_content=heated-glove">print a heated glove</a>, leveraging NOVA to dispense silver conductive ink onto a cotton substrate in the shape of a hand.[1] The ink material used, <a href="https://www.acimaterials.com/product/sh5025/">ACI SH5025 Printed Fixed Resistance Heater Ink</a>, was selected because it is specifically engineered for heating applications and for use with elastomeric substrates. This use case resulted in a wearable heating element capable of reaching up to 40°C when powered by a 12V power source. For comfort and safety, the heating element is contained with an internal liner that makes direct contact with the wearer’s hand. The device could also be adapted for enhanced portability through the integration of an embedded power supply. <img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1761202855822-1761202855822.jpeg" width="624" height="351" class="fr-fic fr-dii" />NOVA dispensing ACI SH5025 printed fixed resistance heater ink on cotton to make a heated mitten.In a similar proof of concept, Voltera printed a <a href="https://www.youtube.com/watch?v=wrC1HO6YrDo">wearable pocket heater</a> that used Celanese Intexar (PE874) silver ink and TPU as a substrate.[2] This flexible heating element—printed in less than 15 minutes—was integrated directly into a denim pocket and, when connected to a battery pack stored in the pocket, reached up to 45-50°C within a minute. This localized, wearable heating device could also be adapted for other applications, like in a military jacket pocket or boots to keep troops warm in harsh, cold conditions.<h2>Wearable sensors for continuous health monitoring</h2>In the military, health monitoring is a key component in maintaining operational readiness, taking a preventative approach to injury and illness, and enhancing recovery and rehabilitation. Traditionally, monitoring a soldier’s condition required periodic manual checks by medics. However, keeping a close eye on individual soldiers’ health is not always possible in field missions. Fortunately, wearable health sensors are making continuous health monitoring possible at scale, ensuring that every soldier is accounted for.NOVA can play a role in the development of these wearable devices, which can track an individual soldier’s health and vitals while in training or in the field. By printing biocompatible materials, like gold and silver inks, onto flexible substrates that conform to the body, it is possible to deploy discreet monitoring devices that soldiers can wear without compromising comfort. For example, Voltera conducted a proof of concept in which it <a href="https://www.youtube.com/watch?v=8gadvYmvLP8">printed an insole</a> embedded with  force sensitive resistors (FSR) capable of detecting physical pressure and weight distribution.[3] The sensors, printed using stretchable silver ink and a TPU substrate, were applied to a foot-shaped carbon sheet and connected to a breadboard in order to function. This technology could be further developed by defense organizations for posture and gait analysis as well as injury tracking. For example, sensors could be strategically placed on the heel or ball of the foot to monitor weight distribution and balance in real time, providing vital insights into whether a soldier is injured (i.e. if they are relying more on one leg) or fatigued (i.e. if their gait pattern changes).   <img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1761202855833-1761202855833.jpeg" width="624" height="351" class="fr-fic fr-dii" />Conductive traces (Celanese IntexarTM PE874 stretchable silver ink) printed with NOVAElectronics printing has also been used in the development of electrocardiogram (ECG) electrodes, which are placed on the skin to monitor the heart’s electrical activity. In one study, Voltera used biocompatible gold ink and stretchable silver ink on a TPU substrate, to create a set of <a href="https://www.voltera.io/use-cases/white-papers/printing-ecg-electrodes-biocompatible-gold-ink-tpu?utm_campaign=Wevolver&amp;utm_source=wevsite&amp;utm_medium=wearable-combat-devices&amp;utm_content=ecg-electrodes">dry ECG electrodes</a>, which are easier and more comfortable to wear than conventional ECG electrodes, demonstrating NOVA’s ability to drive innovation in this area.[4] In a defense context, similar ECG sensors could be integrated into shirts or chest straps for real-time monitoring of vitals, giving medics continuous data and alerting them to notable changes (i.e. elevated heart rate), which could indicate stress or danger.Of course, insole pressure monitors and dry ECG electrodes are just the tip of the iceberg for printed health monitoring devices: printed sensors could also be developed to track health metrics like hydration, fatigue, and more, to ensure troops are at their optimal physical and cognitive performance.<h2>Body-worn printed batteries for better communication</h2>Printed electronics can also transform the state of wearable communication devices, leading to improvements for real-time, hands-free communication that can help track troops and equipment in the field. Voltera’s NOVA platform in particular can be used to develop and print ultrathin, compact batteries that can be worn alongside communication devices, powering anything from encrypted radios, to GPS trackers, to motion-tracking sensors and unburdening soldiers as they are increasingly equipped with networked devices.[5] The potential of printing body-worn batteries is great in the defense sector and Voltera recently demonstrated how its NOVA platform can be used to exploit this potential. In one study, the company printed an ultrathin (500 µm), <a href="https://www.voltera.io/use-cases/white-papers/printing-magnesium-zinc-battery-saral-inks-pet?utm_campaign=Wevolver&amp;utm_source=website&amp;utm_medium=wearable-combat-devices&amp;utm_content=battery">seven-layer zinc-manganese battery</a> on a flexible PET substrate.[6] This proof of concept demonstrated how NOVA can print compact energy storage devices that can be customized in terms of shape and size to meet application requirements. The printing process can also be used with other types of inks, including lithium cobalt oxide, less flammable carbon nanotubes, and non-flammable vanadium oxide. <img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1761202855841-1761202855841.jpeg" width="624" height="352" class="fr-fic fr-dii" />NOVA printing the first layer of battery cells.For defense applications, NOVA could therefore print compact batteries that conform to the wearer and provide power to wearable electronics, ensuring round-the-clock communication and function, while eliminating bulky equipment and wires.<h2>Conclusion</h2>The NOVA printing platform thus has the potential to be an indispensable tool to defense organizations, empowering them to enhance combat-specific wearable technologies that improve everything from thermal management, to health monitoring, to communications. To learn more about Voltera’s industry-leading solution and its applications in the defense sector, don’t hesitate to <a href="https://www.voltera.io/book-a-meeting?utm_campaign=Wevolver&amp;utm_source=website&amp;utm_medium=wearable-combat-devices&amp;utm_content=get-in-touch">get in touch</a> with a member of the Voltera team.  <h2>References</h2>[1] Printing Silver Conductive Ink on Cotton Fabric [Internet]. Voltera, 2025. <a href="https://www.voltera.io/use-cases/white-papers/printing-silver-conductive-ink-cotton-fabric">https://www.voltera.io/use-cases/white-papers/printing-silver-conductive-ink-cotton-fabric</a> [2]  Wearable pocket heater with stretchable silver on TPU [PDF]. Voltera, 2025.[3] Insole pressure sensor with stretchable silver on TPU [PDF]. Voltera, 2025.[4] Printing ECG Electrodes with Biocompatible Gold Ink on TPU [Internet]. Voltera, 2025. <a href="https://www.voltera.io/use-cases/white-papers/printing-ecg-electrodes-biocompatible-gold-ink-tpu">https://www.voltera.io/use-cases/white-papers/printing-ecg-electrodes-biocompatible-gold-ink-tpu</a> [5] Lafontaine, Dan. Conformal battery unburdens Army's networked Soldiers [Internet]. U.S. Army, July 17, 2013. <a href="https://www.army.mil/article/107362/conformal_battery_unburdens_armys_networked_soldiers">https://www.army.mil/article/107362/conformal_battery_unburdens_armys_networked_soldiers</a> [6] Printing a Magnesium Zinc Battery with Saral Inks on PET [Internet]. Voltera, 2025. <a href="https://www.voltera.io/use-cases/white-papers/printing-magnesium-zinc-battery-saral-inks-pet">https://www.voltera.io/use-cases/white-papers/printing-magnesium-zinc-battery-saral-inks-pet</a>

How Voltera's NOVA materials dispensing system can empower defense and military organizations to develop cutting-edge wearable devices for optimal physical and cognitive performance in the field.

Printed Electronics at the Forefront of Wearable Combat Devices

Wearable or implantable devices to monitor biological activities, such as heart rate, are useful, but are typically made of metals, silicon, plastic and glass and must be surgically implanted. A research team in the McKelvey School of Engineering at Washington University in St. Louis is developing bioelectronic hydrogels that could one day replace existing devices and have much more flexibility.<a href="https://engineering.washu.edu/faculty/Alexandra-Rutz.html">Alexandra Rutz</a>, assistant professor of biomedical engineering, and <a href="https://engineering.washu.edu/news/2024/Engineering-Curiosity-with-Anna-Goestenkors.html">Anna Goestenkors</a>, a fifth-year doctoral student in Rutz’s lab, created novel granular hydrogels composed of microparticles that could be injected into the body, spread over tissues or used to encapsulate cells and tissue all while being electronically conducting for monitoring and stimulating biological activity. Results of their research were published Oct. 8 in Small.The microparticles are spherical hydrogels made from the conducting polymer known as PEDOT:PSS. When packed tightly, they are similar to wet sand or paste: They hold as a solid with micropores, but they can also be 3D printed or spread into different shapes while maintaining their structure or redistributed into individual microparticles when placed in liquid. “Granular hydrogels have not been widely studied for these applications, but we have found that this material has the potential to be injected with a needle at the site," Rutz said. “We’re trying to borrow techniques from tissue engineering to try to have these electronically conducting materials emulate properties of the body while being able to leverage the function of these materials to have more sophisticated ways of doing it.”Goestenkors said when the particles are packed closely together, there are empty spaces between them that create porosity on the micron scale or the cell scale, which is unique to a lot of the hydrogel materials, Goestenkors said.“Because the particles’ connections aren’t permanent, they can move relative to each other, and the material will flow like a liquid when you apply a certain amount of force that allows them to be injected or extruded,” she said. “But when you remove that force, they recover those connections and become more of a paste-like solid again, so it’s a very adaptable material.”The individual particles range in diameter from 10 to 100 micrometers and can be extruded through a 3D printing nozzle to form strands, Goestenkors said. She created them through a water and oil emulsion, similar to making an oil-and-vinegar salad dressing. After heating the oil, she added the polymer. When stirred, the polymer broke into tiny droplets in the oil, and the elevated temperature crosslinked the polymer to create stable hydrogels. Heating the oil to 90 C created the best-formed particles following oil removal.As part of their research, they conducted an experiment with locusts in the lab of <a href="https://engineering.washu.edu/faculty/Barani-Raman.html">Barani Raman</a>, the Dennis &amp; Barbara Kessler Professor and co-director of the Center for Cyborg and BioRobotic Research (CyBoR). Goestenkors put small clumps of the particles on the tips of the locust antennae, where there are olfactory receptor neurons. The particles allowed them to measure local field potentials that correspond with an odor being sensed by the locust. “With further development, we envision these conducting granular hydrogels could be used as 3D printed customized electrodes that can conform to topographically diverse surfaces or completely encapsulate biological components, tissue engineering scaffolds or injectable therapies,” Rutz said.Rutz and Goestenkors are inventors of a U.S. patent application that covers fabrication and applications of conducting polymer microparticles and conducting granular hydrogels. They are working with the university’s Office of Technology Management, which is assisting in protecting the intellectual property and advancing commercialization efforts.<hr />Goestenkors AP, Yu JS, Park J, Wu Y, Vargas Espinoza CJ, Friedman LC, Okafor SS, Liu T, Chatterjee S, Debnath A, Semar BA, O’Hare CP, Alvarez RM, Singamaneni S, Raman B, Rutz AL. PEDOT:PSS Microparticles for Extrudable and Bioencapsulating Conducting Granular Hydrogel Bioelectronics. Small. Oct. 8, 2025. DOI: <a href="https://doi.org/10.1002/smll.202506438">https://doi.org/10.1002/smll.202506438</a>This research was supported by Washington University in St. Louis through the Women's Health Technologies Collaboration Initiation Grant, Center for Regenerative Medicine Seed Grant, Ovarian Cancer Research Innovation Fund Award, the McDonnell Center for Cellular and Molecular Neurobiology Small Grant, and the Center for Cyborg and BioRobotic Research.

Anna Goestenkors, a doctoral student in Alexandra Rutz’s lab, fabricates novel granular hydrogels composed of microparticles that could be injected into the body, spread over tissues or used to encapsulate cells and tissue all while being electronically conducting for monitoring and stimulating biological activity. (Credit: Anna Goestenkors)

Research in Alexandra Rutz's lab creates hydrogels that could measure biological activity

Extrudable hydrogels act as bioelectronic conductors

Stanford pediatric surgeon <a href="https://profiles.stanford.edu/james-dunn">James Dunn</a> specializes in helping children with short gut syndrome, a congenital disease in which children are born with short intestinal tracts. “I’ve been working to grow new intestinal tissue by applying a mechanical force to the intestine – stretching it,” Dunn, who is a professor of surgery in the <a href="https://med.stanford.edu/">School of Medicine</a>, explained. “But I didn’t have a way to demonstrate that this new tissue is functioning exactly like normal intestine.”That is when Dunn reached out to <a href="https://profiles.stanford.edu/zhenan-bao">Zhenan Bao</a>, the K.K. Lee Professor of Chemical Engineering and director of the <a href="https://wearable.su.domains/">Stanford Wearable Electronics Initiative (eWEAR)</a>, who has drawn worldwide attention for developing skinlike electrical circuits, like her electronic <a href="https://news.stanford.edu/stories/2023/05/soft-e-skin-talks-brain">skin</a> that can sense the weight of a butterfly and the heat of a flame. The result of their collaboration is NeuroString, a multichannel, soft, thread-like implantable biosensor/stimulator.NeuroString is just a quarter of a millimeter in diameter – about the width of a human hair – and can host hundreds to thousands of independent electronic “channels,” each of which can sense neurochemicals, stimulate muscle or nerve, sense gut movement patterns, or monitor the activity of a single neuron, among many other promising possibilities. The team details its NeuroString work in <a href="https://www.nature.com/articles/s41586-025-09481-2">the latest issue</a> of the journal Nature.<h2>Unmet needs</h2>“There is great need, in both research and clinical settings, for these minimally invasive sensing and stimulation bioelectronics,” said co-author <a href="https://med.stanford.edu/profiles/xiang-qian">Xiang Qian</a>, co-director of Stanford’s <a href="https://wearable.su.domains/">eWear Initiative</a> and a medical doctor who specializes in neuromodulation to treat severe pain. Currently, clinical tools boil down to rigid and bulky needlelike probes or stiff wires with limited functionality.“It is a high-density electronic fiber that’s also exceptionally biocompatible due to its softness,” Qian said. “It can stay inside the body for months at a time or longer, and it’s so soft and small that it can be implanted without discomfort or harm to the patient.”Beyond the thin and soft circuitry, Bao’s team also developed a clever roll-up fabrication technique. They prepared <a href="https://www.youtube.com/watch?v=pV09v_n5bnM">a video of the method</a> that shows a prototype with 20 electronic channels laid out on a thin, transparent skin-like material. The film is then rolled tightly into a spindle so thin it is described as one-dimensional. All 20 electrical connecting wires in the example are spiraled inside the string, like the layers in a <a href="https://en.wikipedia.org/wiki/Swiss_roll">Swiss roll</a>, while the 20 sensors are exposed on the surface. Each independent sensor/stimulator is connected by a discrete wire running the length of the NeuroString to deliver valuable data.<iframe width="640" height="360" src="https://www.youtube.com/embed/pV09v_n5bnM?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0"></iframe>Video demonstrates how a two-dimensional thin film with micropatterned electronic devices is rolled into a one-dimensional fiber. | Image credit: Chengyi Xu; video courtesy Bao LabBao said the approach allows exquisite control of the positioning and distribution of the active components, and her team has demonstrated a fiber with a remarkable 1,280 individual channels. “Many more channels can be added if we make longer fibers,” says <a href="https://baogroup.stanford.edu/people/muhammad-khatib">Muhammad Khatib</a>, a postdoctoral fellow and first author on the paper.<h2>New frontiers</h2>On a practical front, to demonstrate the effectiveness of their new electronic fiber, Bao, Dunn, and team used the implanted NeuroString to monitor the intestines of a pig and to observe individual neurons in the brain of a mouse over four months.Dunn explained that, in his field, measuring basic things like how the intestine contracts without interrupting normal activities may sound easy, but it has so far been out of reach, not to mention that the intestine also does a lot of things like absorbing nutrients and secreting biochemicals like serotonin that he might want to track.“To be able to stimulate the muscle and measure all these other things in a specific region will be transformative for my research and, potentially, my medical practice – NeuroString is a platform for us to understand how the intestine works,” Dunn said.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1758371540950-images+%281%29.jpeg" style="width:100%px" class="fr-fic fr-dib" />A cross-section of the NeuroString. Multiple electrical channels can be spiraled inside the string, like the layers in a Swiss roll. It’s rolled so tightly that the string can be described as one-dimensional. | Courtesy Bao LabThe research team anticipates that such devices could have far-reaching impacts in fields ranging from neuroscience to gastroenterology. They envision that it could yield robotic pills that can be swallowed to diagnose medical conditions throughout the gastrointestinal tract or be wrapped around an optical fiber to create an ultra-thin endoscope.Qian thinks NeuroString could introduce an era of minimally invasive, closed-loop neural stimulation techniques – devices that can both sense nerve dysfunction and intervene in an instant. “You only need to stimulate when you detect this abnormal electric signal to shut it down,” Qian said of his device, which he is currently testing in mice. “It will be ten times smaller than conventional alternatives and much safer with fewer complications. It would be groundbreaking.”In a tubelike form, Bao says the NeuroString could deliver drugs to precise locations inside the body. Imagine a new form of implantable insulin pump that both senses blood sugar and delivers the life-sustaining hormone on demand, much like the pancreas.In brain studies, NeuroString could deliver light for optogenetics and sense its effect on local neurons to optimize light intensity. And these potential applications are only the in-body opportunities for NeuroString. In other practical outlets, Bao said, NeuroString might lead to a new era of smart fabrics and textiles, wearable devices, and soft robotics.<h2>Synthetic organs</h2>One area of research that Bao finds particularly intriguing is organoids – lab-grown tissues that function like real tissue for use in research. Her team, together with <a href="https://profiles.stanford.edu/xiaoke-chen">Xiaoke Chen</a>, associate professor of biology in the <a href="https://humsci.stanford.edu/">School of Humanities and Sciences</a>, initially developed a NeuroString with only one neurochemical sensor seeded by <a href="https://biox.stanford.edu/highlight/stretchable-probe-measures-brain-chemicals-central-parkinson%E2%80%99s-depression-and-gut-disease">Bio-X seed funding</a>. The team’s initial development of this advanced NeuroString came under the aegis of the <a href="https://neuroscience.stanford.edu/news/toolmakers-aim-untangle-fundamental-challenges-neuroscience">Brain Organogenesis Big Ideas in Neuroscience</a> program at the <a href="https://neuroscience.stanford.edu/">Wu Tsai Neurosciences Institute</a>.The Brain Organogenesis program is pursuing new models of human brain circuits to understand how the brain develops and what is happening when things go wrong, as in numerous neurological and psychiatric diseases from depression to Parkinson’s disease. Bao said her NeuroString technology was inspired by the need for soft sensors that can be embedded inside the growing organoids that will allow researchers deeper insights into the function and biochemistry of these lab-grown mini-organlike structures to mimic human tissues.“We hope to thread these thin electronics inside and throughout organoids, to promote and monitor their growth,” Bao said. “That’s our vision and it’s pretty exciting.”

The NeuroString is just a quarter of a millimeter in diameter – about the width of a human hair – and can host hundreds to thousands of independent electronic channels that could be used to sense, stimulate, or monitor parts of the human body. | Courtesy Bao Lab

Developed by Stanford researchers, NeuroString is a hair-thin multichannel biosensor and stimulator with promising potential applications in drug delivery, nerve stimulation, smart fabrics, and more.

Soft bioelectronic fiber can track hundreds of biological events simultaneously

Scientists are increasingly finding that the gastrointestinal (GI) tract plays a vital role in our overall health. While its main functions center around digestion, the GI tract is also involved in the production of hormones, immune cells, and even neurotransmitters that can affect mood and brain function. As such, the GI tract is host to many different biomarkers that can be useful for identifying, monitoring, and treating disease—everything from short-chain fatty acids that are indicators of metabolic syndrome to cytokines that are biomarkers of inflammation.But there is no technology currently available that can easily profile this metabolic, molecular information from the GI tract. Traditional evaluation methods involve either fecal analysis or biopsy, which are invasive, expensive, and cannot provide real-time profiling across the GI tract.Now a team of Caltech engineers has developed a smart capsule called PillTrek, which can measure pH, temperature, and a variety of different biomarkers. It incorporates simple, inexpensive sensors in a miniature wireless electrochemical workstation that relies on low-power electronics. PillTrek is tiny, measuring 7 millimeters in diameter and 25 millimeters in length, making it smaller than commercially available capsule cameras used for endoscopy but capable of executing a range of electrochemical measurements.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756252877901-Wei_Gao-Smart-Capsule-PillTrek_QuarterScale-WE.width-450.jpg" style="width:100%px" class="fr-fic fr-dib" />The PillTrek smart capsule measures just 7 millimeters in diameter and 25 millimeters in length. Credit: Jihong Min and Wei Gao"We designed this pill to be a very versatile platform," says <a href="https://www.eas.caltech.edu/people/weigao">Wei Gao</a>, professor of medical engineering at Caltech and a Heritage Medical Research Institute Investigator. "From an electrochemical-sensing point of view, it is very powerful. It has the ability to measure metabolites, ions, hormones such as serotonin and dopamine, possibly even proteins as well. And all within the gut, which is a complex environment."The scientists describe the capsule in a new <a href="https://www.nature.com/articles/s41928-025-01407-0">paper</a> in the journal Nature Electronics. The lead authors of the paper are Jihong Min, a postdoctoral scholar fellowship trainee in medical engineering at Caltech, and Hyunah Ahn, a visitor in medical engineering at Caltech and graduate student at the Korea Advanced Institute of Science and Technology (KAIST).As a proof of concept, PillTrek was used in the study to measure pH and temperature as well as changing levels of glucose and the neurotransmitter serotonin in animal models.Gao points out that the electrochemical workstation within the capsule is reconfigurable. A variety of different sensors could easily be swapped into place to enable measurements of different parameters in the gut. His team <a href="https://www.caltech.edu/about/news/printable-molecule-selective-nanoparticles-enable-mass-production-of-wearable-biosensors">previously developed</a> a technique for 3D printing inexpensive sensors on sheets of plastic substrate. That technique can be used to mass-produce the sensors for PillTrek.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1756252898839-Wei_Gao-Smart-Capsule-PillTrek_3-WEB.width-450.jpg" style="width:100%px" class="fr-fic fr-dib" />A 3D-printed biosensor array is at the heart of the electrochemical workstation inside the PillTrek smart capsule. Credit: Jihong Min and Wei GaoIn terms of next steps, Gao says that he is working with co-author <a href="https://www.eas.caltech.edu/people/azita">Azita Emami</a>, the Andrew and Peggy Cherng Professor of Electrical Engineering and Medical Engineering at Caltech, to look into wireless power transfer and smaller electronics that would make PillTrek even smaller and lower power."Ingestible capsules have significant potential in diagnosis, monitoring, and management of chronic conditions, but previous devices were very limited in terms of their sensing capabilities, lifetime, and size," says Emami, who is also director of the Center for Sensing to Intelligence. "This work is an important translational step toward devices that can provide meaningful medical information for patients and physicians."Additional authors of the paper are Heather Lukas (MS '21), Xiaotian Ma, Rinni Bhansali, Sung-Hyuk Sunwoo, Canran Wang (MS '23), Yadong Xu, Dickson R. Yao, and Gwangmook Kim of Caltech, as well as Zhaoping Li and Tzung K. Hsiai of the David Geffen School of Medicine at UCLA and Hee-Tae Jung of KAIST.The work was supported by funding from the National Science Foundation, the National Institutes of Health, the American Cancer Society, the Army Research Office, the US Army Medical Research Acquisition Activity, the National Research Foundation of Korea, the Heritage Medical Research Institute, and the KAIST-UC Berkeley-VNU Global Climate Change Research Center. The team also received critical support and infrastructure from the <a href="https://kni.caltech.edu/">Kavli Nanoscience Institute</a> at Caltech.

A team of Caltech engineers has developed a smart capsule called PillTrek, which can measure pH, temperature, and a variety of different biomarkers. It incorporates simple, inexpensive sensors in a miniature wireless electrochemical workstation that relies on low-power electronics.

New "Smart Capsule" to Study the Health of the GI Tract

Precision fluid dispensers play a crucial role in manufacturing the products we interact with regularly. They are used in a wide range of industries, so much so, we often forget their role in our everyday lives.In this article, we will provide a brief overview of fluid dispensing systems, highlight their applications, discuss common challenges with the technology, and share an overview of <a href="https://www.voltera.io/products/nova">NOVA</a>, our materials dispensing system.&nbsp;<h2>What are precision fluid dispensing systems?</h2>Precision fluid dispensing systems allow users to deposit micro amounts of assembly fluids onto a substrate in targeted areas. When dealing in microlitres or nanolitres, the amount of fluid deposited is often nearly impossible to control with most manual pumps and flowmeters. These systems were developed to implement control, precision, accuracy, and consistency in applications requiring microdispensing.The two most common types of systems for fluid dispensing are:&nbsp;<h4>Non-contact&nbsp;</h4>Also known as jet dispensing or jetting. In a jetting system, the fluid is deposited or “jetted” onto the substrate from a distance.&nbsp;<h4>Contact&nbsp;</h4>This method uses a valve to deposit material in a highly controlled manner. It offers compatibility with a wider range of fluids compared to non-contact systems. Some examples of contact systems include:<ul><li>Pneumatic/time pressure: Pulses of air engage the top of the plunger in a specific pattern, driving the plunger forward in the syringe and depositing material.</li><li>Mechanical positive displacement: A rod or piston that forces fluid out of the cartridge.</li><li>Auger: A motor enables the auger screw to rotate, pulling material from the reservoir and guiding it towards the nozzle.</li><li>Progressive cavity (PC) pump: Similar to an auger system, PC pumps utilize a rotor and stator to fill tightly sealed cavities with precise amounts of fluid which are then pushed towards the nozzle, enabling larger consistent deposits with high viscosity fluids.</li></ul><h3>Fluid dispensing applications</h3>Numerous industries utilize dispensing systems for depositing materials, such as:<ul><li>Electronics: <a href="https://www.voltera.io/blog/what-is-solder-paste">Solder pastes</a>, conductive adhesives, <a href="https://www.voltera.io/blog/role-conductive-inks-additive-electronics-manufacturing">conductive inks</a>, flux, coatings, underfill adhesives, and dam and fill.&nbsp;</li><li>Medical: <a href="https://www.voltera.io/use-cases/white-papers/printing-ecg-electrodes-biocompatible-gold-ink-tpu">Biomarker detection</a>, and in- and on-body <a href="https://www.voltera.io/blog/printed-tattoo-electrodes">biomedical sensors</a>.&nbsp;</li><li><a href="https://www.voltera.io/blog/copper-rfid-tag">RFID</a>: Eco-friendly and cost effective non-contact data transfer and localization systems.</li></ul>Recent <a href="https://www.precedenceresearch.com/fluid-dispensing-systems-market">research</a> indicates the electrical and electronics assembly segment was the leading global market for fluid dispensing equipment in 2024.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1752481085375-6824a6de43f1ffa35b392ab0_precision-fluid-dispensing-system-market-share.webp" style="width: 100%px;" class="fr-fic fr-dib">Fluid dispensing systems market share, by application in 2024. Source:&nbsp;<a href="https://www.precedenceresearch.com/fluid-dispensing-systems-market">Precedence Research</a><h3 id="isPasted">Materials used in fluid dispensing&nbsp;</h3>Precision fluid dispensers enable a diverse range of <a href="https://www.voltera.io/blog/compatibility-guide-inks-substrates">material compatibility</a>. Some of the most common materials used in these systems are:<ul><li>Flux:&nbsp;A chemical compound used in preparing metal surfaces for soldering.&nbsp;</li><li>Conductive ink: Printable materials that are capable of conducting electricity.&nbsp;</li><li>Lubricant: Oily materials that help reduce friction in surfaces that contact each other.&nbsp;</li><li>Solder paste: Powdered metal solder that is suspended in flux. &nbsp;</li><li>Adhesive:&nbsp;Substances that are capable of&nbsp;holding at least two surfaces together permanently.</li><li>Sealants: Materials that attach at least two surfaces together, filling the space between them.</li><li>Conformal coatings: A film applied over components that provides protection against contaminants and environmental factors.</li><li>Epoxy underfill:&nbsp;An epoxy-material used in PCBs to connect a chip to the board through capillary action.</li></ul>In the same research report referenced above, the graph below shows the growth of fluid dispensing systems of various materials in the global market.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1752481145334-6824a7182f16b031a170df7a_precision-fluid-dispensing-system-global-market.webp" style="width: 100%px;" class="fr-fic fr-dib">Fluid dispensing systems market share, by region, 2024. Source:&nbsp;<a href="https://www.precedenceresearch.com/fluid-dispensing-systems-market" id="isPasted">Precedence Research</a>Though the Asia-Pacific region accounted for 46% of the global revenue for fluid dispensing equipment in 2024, the global demand is projected to increase for systems that are compatible with lubricant, solder paste, adhesives, and sealants. This is primarily driven by advancements in electronics and automotive manufacturing [1].<h2>Benefits of precision fluid dispensing&nbsp;</h2>The primary benefit of precision fluid dispensers is the ability to print high-resolution patterns and features quickly. They are designed to implement control methods to ensure high quality results are achieved. Many applications developed using these systems require consistent prints in high volume orders, so repeatability is key.These systems can also be integrated into production lines to significantly reduce development time. They offer customizable features like interchangeable dispensers and programmable settings. Swappable dispensers allow users to disperse different types of material that would otherwise take longer to complete using manual processes, or even require a different tool altogether. A user can switch from a precision nozzle designed for depositing an adhesive ink, to a nozzle designed for spraying a coating in a matter of seconds.<h2>Challenges with precision dispensing systems</h2>One of the primary challenges that exists is finding the right system for your application. Unless you’re a material scientist, it is easy to become overwhelmed by technical specifications, even if you know your application’s requirements. There is no one-size-fits-all materials dispensing system on the market; each has its own advantages and disadvantages, most often tailored to specific applications. Even after settling on a system to purchase, it's extremely common to face difficulties with material reliability and flow.Let’s say you have your system, the material, and a substrate. How do you tell the system where to deposit the fluid? How much should it deposit? When and where should it start and stop?&nbsp;Balancing these aspects while also adjusting settings to manage consistency, material leakage, and quality results, is often no easy task — especially without an intuitive user interface.<h2>NOVA: Voltera’s precision fluid dispensing system</h2><a href="https://www.voltera.io/products/nova">NOVA</a> is a precision materials dispensing system that dispenses screen-printable materials (1,000 to 1,000,000 cP) on flexible, stretchable, conformable, and biocompatible materials, as well as rigid substrates. It is ideal for:<ul><li>Flexible hybrid electronics R&amp;D</li><li>Novel materials research</li><li>Precise material dispensing</li><li>Seamless transition to mass production</li></ul>In 2025, we released <a href="https://www.voltera.io/blog/print-multilayer-flexible-stretchable-circuits-nova">Plan</a>, a software feature that enables multilayer printing and print job editing for NOVA, further improving user experience for printing multi-material and multilayer circuit designs.&nbsp;<h3>Benefits of NOVA</h3><ul><li>Achieve repeatable results with close-loop pressure feedback, temp-controlled dispensing, and an optimized algorithm for multilayer printing.</li><li>Stack up to four layers of materials and visualize multilayer print sequences before execution.</li><li>Experiment with a wide range of printable materials, from conductive inks and adhesives to solder paste on both flexible and rigid substrates.</li><li>Change designs on the fly and iterate without screens or stencils, eliminating delays and reducing costs while prototyping in-house.</li><li>…and more</li></ul>For technical specifications of NOVA, <a href="https://www.voltera.io/technical-specifications">click here</a>.&nbsp;<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1752481175307-6824a7a66bae719bafe5740e_precision-fluid-dispensing-system-nova-carbon.webp" style="width: 100%px;" class="fr-fic fr-dib">NOVA printing a functional carbon ink developed by Voltera’s Applications team on PET sheet<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1752481189539-6824a7e2eb0941c0b3792081_precision-fluid-dispensing-system-nova-stretchable.webp" style="width: 100%px;" class="fr-fic fr-dib">NOVA printing the ACI SH5025 printed fixed resistance heater ink on cotton fabric<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1752481209704-6824a801659d73890470e99d_precision-fluid-dispensing-system-nova-gold.webp" style="width: 100%px;" class="fr-fic fr-dib">NOVA printing Creative Materials’ EXP 2613-40 biocompatible gold ink on TPU to make ECG electrodes<h2 id="isPasted">Conclusion</h2>As additive manufacturing continues to revolutionize research outcomes and product development, innovators are searching for the right solution to meet their goals. They’re looking to accelerate development timelines and find cost effective methods for achieving reliable, high quality results.If you would like to see if&nbsp;<a href="https://www.voltera.io/products/nova">NOVA</a> is a fit for your application,&nbsp;<a href="https://meetings.hubspot.com/royperez/v-one-or-nova-demo?__hstc=13863464.442141b0ea5e62795d6bc78aca77beb8.1746398746144.1746398746144.1752480938948.2&__hssc=13863464.1.1752480938948&__hsfp=2848152525">book a meeting</a> with one of our application specialists.&nbsp;<hr><h2>References</h2>[1] Precedent Research,&nbsp;<a href="https://www.precedenceresearch.com/fluid-dispensing-systems-market">Fluid Dispensing Systems Market Size, Share, and Trends 2025 to 2034</a>, 2025.

In this article, we will provide a brief overview of fluid dispensing systems, highlight their applications, discuss common challenges with the technology, and share an overview of NOVA, our materials dispensing system.

What are Precision Fluid Dispensing Systems?

Bioengineering researchers at the <a href="https://seas.harvard.edu/">Harvard John A. Paulson School of Engineering and Applied Sciences</a> (SEAS) have developed a soft, thin, stretchable bioelectronic device that can be implanted into a tadpole embryo’s neural plate, the early-stage, flat structure that folds to become the 3D brain and spinal cord.The researchers demonstrated that the device could integrate seamlessly into the brain as it develops and record electrical activity from single brain cells with millisecond precision, with no impact on normal tadpole embryo development or behavior.These so-called cyborg tadpoles offer a glimpse into a future in which profound mysteries of the brain could be illuminated, and diseases that manifest in early development could be understood, treated, or cured.“Autism, bipolar disorder, schizophrenia – these all could happen at early developmental stages,” said Jia Liu, <a href="https://seas.harvard.edu/person/jia-liu">Assistant Professor of Bioengineering at</a> SEAS. “There is just no ability currently to measure neural activity during early neural development. Our technology will really enable an uncharted area.”The research is published in <a href="https://www.nature.com/articles/s41586-025-09106-8" target="_blank">Nature</a>.In vertebrate embryos, the folding and expansion of the neural plate into the neural tube, which is the precursor to the brain and spinal cord, involves complex morphological changes over millisecond time scales, Liu said. By integrating their stretchable device into the neural plate, the researchers showed they could stably and continuously monitor brain activity during each subsequent embryonic stage.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1751749445397-tadpole_fig_1.jpg" style="width: 100%px;" class="fr-fic fr-dib">A schematic of the stepwise implantation of soft mesh electronics into the tadpole embryo brain.In the past, scientists have used patch-clamp or metal electrodes inserted into mature brains to record electrical activity of single neurons with high resolution. Further breakthroughs in tissue-like microelectronics from Liu’s previous work have made single-cell brain recording even less invasive. Yet in fully developed brains, neurons connect with each other at nanometer resolutions; no matter how soft and small brain probes are, implanting them requires at least some neuronal damage, Liu said. &nbsp;“If we can fully leverage the natural development process, we will have the ability to implant a lot of sensors across the 3D brain noninvasively, and at the same time, monitor how brain activity gradually evolves over time,” Liu said. “No one has ever done this before.” &nbsp;This research builds on a multi-year effort to create soft, flexible, non-invasive bioelectronics for brains, which have the consistency of tofu. In previous studies, the team embedded electrode arrays into petri dishes of stem cells. The thin electrodes stretched and folded with growing tissue and created cyborg heart and <a href="https://seas.harvard.edu/news/2022/02/cyborg-brain-organoids-offer-insight-early-brain-development">brain organoids</a>.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1751749463154-tadpole_fig_3.jpg" style="width: 100%px;" class="fr-fic fr-dib">Immunostaining depicts the contact between tadpole brain tissue and mesh electronics (red).&nbsp;Though the organoid studies were successful, integrating nanoelectronics into amphibian embryos posed new challenges, according to Liu. “It turns out tadpole embryos are much softer than human stem cell-derived tissue,” he said. “We ultimately had to change everything, including developing new electronic materials.”The researchers made a new type of implant out of&nbsp;<a href="https://seas.harvard.edu/news/2024/01/long-lasting-neural-probe">fluorinated elastomers</a>, which are as soft as biological tissue but can be engineered into highly resilient electronic components that can withstand nanofabrication processes and house multiple sensors for recording brain activity.The fluorinated elastomer, called perfluoropolyether-dimethacrylate, is intellectual property protected by Harvard’s Office of Technology Development, which licensed the technology to the start-up company&nbsp;<a href="https://axoft.us/" target="_blank">Axoft</a> for further development. Liu co-founded Axoft in 2021, and the company is focused on development of&nbsp;<a href="https://www.medrxiv.org/content/10.1101/2025.04.24.25326126v3" target="_blank">scalable, soft bioelectronics</a> for brain-machine interface applications.<hr>The study’s first author is Harvard postdoctoral fellow Hao Sheng. Co-authors were Ren Liu, Qiang Li, Zuwan Lin, Yichun He, Thomas S. Blum, Hao Zhao, Xin Tang, Wenbo Wang, Lishuai Jin, Zheliang Wang, Emma Hsiao, Paul Le Floch, Hao Shen, Ariel J. Lee, Rachael Alice Jonas-Closs, James Briggs, Siyi Liu, Daniel Solomon, Xiao Wang, Jessica L. Whited, and Nanshu Lu.The research received federal support from the National Institutes of Health / National Institutes of Mental Health under grant No. 1RF1MH123948; the National Science Foundation / Emerging Frontiers in Research and Innovation under grant No. 2422348; and the National Institutes of Health / National Institute of Child Health and Human Development under grant No. 1R01HD115272.

Thin electrode arrays integrate seamlessly into developing embryos' brains

Cyborg tadpoles with soft, flexible neural implants

"Our work provides a proof-of-concept showing a path to a single-step method that could be used to identify and measure nucleic acids and proteins," says Paul Rothemund (BS '94), a visiting associate at Caltech in computing and mathematical sciences, and computation and neural systems.A<a href="https://www.pnas.org/doi/10.1073/pnas.2311279121">&nbsp;paper</a> describing the work recently appeared in the journal&nbsp;Proceedings of the National Academy of Sciences. The lead authors of the paper are former Caltech postdoctoral scholar Byoung-jin Jeon and current graduate student Matteo M. Guareschi, who completed the work in Rothemund's lab.In 2006, Rothemund published the&nbsp;<a href="https://www.nature.com/articles/nature04586">first paper on DNA origami</a>, a technique that provides simple yet exquisite control over the design of molecular structures at the nanoscale using nothing more than DNA.Essentially DNA origami enables long strands of DNA to fold, through self-assembly, into any desired shape. (In the 2006 paper, Rothemund famously used the technique to create miniature DNA smiley faces measuring 100 nanometers across and 2 nanometers thick). Researchers begin with a long strand of DNA, the scaffold, in solution. Because the nucleotide bases that make up DNA bind in a known way (adenine binds to thymine, and guanine binds to cytosine), the scientists can add hundreds of short sequences of complementary DNA knowing they will bind to the scaffold on either end at known locations. Those short, added pieces of DNA fold the scaffold and give it shape, acting as "staples" that hold the structure together. The technique can then be used to create shapes ranging from a&nbsp;<a href="https://www.newscientist.com/article/dn8853-dna-origami-creates-map-of-the-americas/">map of North and South America</a> to nanoscale transistors.In the new work, Rothemund and his colleagues used DNA origami to create a lilypad-like structure—a flat, circular surface about 100 nanometers in diameter, tethered by a DNA linker to a gold electrode. Both the lilypad and the electrode have short DNA strands available to bind with an analyte, a molecule of interest in solution—whether that be a molecule of DNA, a protein, or an antibody. When the analyte binds to those short strands, the lilypad gets pulled down to the gold surface, bringing 70 reporter molecules on the lilypad (which indicate that the targeted molecule is present) into contact with the gold surface. These reporters are redox reactive molecules, meaning they can easily lose electrons during a reaction. So, when they get sufficiently close to an electrode, an electric current can be observed. A stronger current indicates that more of the molecule of interest is present.Previously, a similar approach to making biosensors was developed using a single DNA strand rather than a DNA origami structure. That earlier work was led by Kevin W. Plaxco (PhD '94) of UC Santa Barbara, who is also an author of the current paper.Caltech's Guareschi points out that the new lilypad origami is large compared to a single DNA strand. "That means it can fit 70 reporters on a single molecule and keep them away from the surface before binding. Then when the analyte is bound and the lilypad reaches the electrode, there is a large signal gain, making the change easy to detect," Guareschi says.The relatively large size of the lilypad origami also means that the system can readily accommodate and detect larger molecules, such as large proteins. In the new paper, the team showed that the two short DNA strands on the lilypad and the gold surface could be used as adapters, making it a sensor for proteins rather than for DNA. In the work, the researchers added the vitamin biotin to those short DNA strands to turn the system into a sensor for the protein streptavidin. Then they added a DNA aptamer, a DNA strand that can bind to a specific protein; in this case, they used an aptamer that binds to a protein called platelet-derived growth factor BB (PDGF-BB), which could be used to help diagnose diseases such as cirrhosis and inflammatory bowel disease."We just add these simple molecules to the system, and it's ready to sense something different," Guareschi says. "It's large enough to accommodate whatever you throw at it—that could be aptamers, nanobodies, fragments of antibodies—and it doesn't need to be completely redesigned every time."The researchers also show that the sensor can be reused several times, with new adapters added each round for different detections. Although the performance slightly degrades over time, the current system could be reused at least four times.In the future, the team hopes the system might also be useful for proteomics—studies that determine what proteins are in a sample and at what concentrations. "You could have multiple sensors at the same time with different analytes, and then you could do a wash, switch the analytes, and remeasure. And you could do that several times," Guareschi says. "Within a few hours, you could measure hundreds of proteins using a single system."Additional authors of the paper, "Modular DNA origami-based electrochemical detection of DNA and proteins," are Jaimie M. Stewart of UCLA; Emily Wu and Ashwin Gopinath of MIT, Netzahualcóyotl Arroyo-Currás of Johns Hopkins University School of Medicine, Philippe Dauphin-Ducharme of the Université de Sherbrooke in Canada; and Philip S. Lukeman of St. John's University in New York.The team used fabrication equipment at the<a href="https://kni.caltech.edu/">&nbsp;Kavli Nanoscience Institute</a> at Caltech. The work was supported by the Army Research Office, the Office of Naval Research, the National Science Foundation, and the Life Sciences Research Foundation supported by Merck Research Laboratories.

A coarse-grained model of the DNA origami lilypad used in the study. The tails hanging down indicate where redox reporters are located. For scale, the diameter of the disk is approximately 80 nm. Credit: Model: Matteo Guareschi/Caltech; Software: OxView

Using an approach called DNA origami, scientists at Caltech have developed a technique that could lead to cheaper, reusable biomarker sensors for quickly detecting proteins in bodily fluids, eliminating the need to send samples out to lab centers for testing.

bioelectronics

Latest Posts