A quasiparticle that can transfer heat under electrical control

Because thermal conductivity in this class of materials can be changed with application of an external electric field at room temperature, they hold promise for use in heat switches for everyday applications, like collection of solar power.
Photo Credit: American Public Power Association

Scientists have found the secret behind a property of solid materials known as ferroelectrics, showing that quasiparticles moving in wave-like patterns among vibrating atoms carry enough heat to turn the material into a thermal switch when an electrical field is applied externally.

A key finding of the study is that this control of thermal conductivity is attributable to the structure of the material rather than any random collisions among atoms. Specifically, the researchers describe quasiparticles called ferrons whose polarization changes as they “wiggle” in between vibrating atoms – and it’s that ordered wiggling and polarization, receptive to the externally applied electrical field, that dictates the material’s ability to transfer the heat at a different rate.

“We figured out that this change in position of these atoms, and the change of the nature of the vibrations, must carry heat, and therefore the external field which changes this vibration must affect the thermal conductivity,” said senior author Joseph Heremans, professor of mechanical and aerospace engineering, materials science and engineering, and physics at The Ohio State University. 

How sound waves trigger immune responses to cancer in mice

The 700kHz, 260-element histotripsy ultrasound array transducer used in Prof. Xu’s lab.
Photo Credit: Marcin Szczepanski/Lead Multimedia Storyteller, Michigan Engineering

Technique pioneered at the University of Michigan could improve outcomes for cancer and neurological conditions

When noninvasive sound waves break apart tumors, they trigger an immune response in mice. By breaking down the cell wall “cloak,” the treatment exposes cancer cell markers that had previously been hidden from the body’s defenses, researchers at the University of Michigan have shown.

The technique developed at Michigan, known as histotripsy, offers a two-prong approach to attacking cancers: the physical destruction of tumors via sound waves and the kickstarting of the body’s immune response. It could potentially offer medical professionals a treatment option for patients without the harmful side effects of radiation and chemotherapy.

Until now, researchers didn’t understand how histotripsy was activating the immune system. A study from last spring showed that histotripsy breaks down liver tumors in rats, leading to the complete disappearance of the tumor even when sound waves are applied to only 50% to 75% of the mass. The immune response also prevented further spread, with no evidence of recurrence or metastases in more than 80% of the animals.

How to make hydrogels more injectable

MIT and Harvard researchers have developed computational models that can predict the properties of materials made from squishy hydrogel blocks.
Image Credit: Courtesy of the researchers

Gel-like materials that can be injected into the body hold great potential to heal injured tissues or manufacture entirely new tissues. Many researchers are working to develop these hydrogels for biomedical uses, but so far very few have made it into the clinic.

To help guide in the development of such materials, which are made from microscale building blocks akin to squishy LEGOs, MIT and Harvard University researchers have created a set of computational models to predict the material’s structure, mechanical properties, and functional performance outcomes. The researchers hope that their new framework could make it easier to design materials that can be injected for different types of applications, which until now has been mainly a trial-and-error process.

“It’s really exciting from a material standpoint and from a clinical application standpoint,” says Ellen Roche, an associate professor of mechanical engineering and a member of the Institute for Medical Engineering and Science at MIT. “More broadly, it’s a nice example of taking lab-based data and synthesizing it into something usable that can give you predictive guidelines that could be applied to things beyond these hydrogels.”

Groundbreaking Biomaterial Heals Tissues From the Inside Out

The biomaterial is based on a hydrogel that Christman's lab developed.
Photo Credit: University of California, San Diego

A new biomaterial that can be injected intravenously, reduces inflammation in tissue and promotes cell and tissue repair. The biomaterial was tested and proven effective in treating tissue damage caused by heart attacks in both rodent and large animal models. Researchers also provided proof of concept in a rodent model that the biomaterial could be beneficial to patients with traumatic brain injury and pulmonary arterial hypertension.

“This biomaterial allows for treating damaged tissue from the inside out,” said Karen Christman, a professor of bioengineering at the University of California San Diego, and the lead researcher on the team that developed the material. “It’s a new approach to regenerative engineering.”

A study on the safety and efficacy of the biomaterial in human subjects could start within one to two years, Christman added. The team, which brings together bioengineers and physicians, presented their findings in Nature Biomedical Engineering.

Lockheed Martin’s First LM 400 Multi-Mission Spacecraft Completed, Ready For Final Testing

Lockheed Martin’s first LM 400 mid-sized, multi-mission spacecraft will launch in 2023 as a technology demonstrator.
Resized Image using AI by SFLORG
Photo Credit: Lockheed Martin Corporation

The first Lockheed Martin LM 400, a flexible, mid-sized satellite customizable for military, civil or commercial users, rolled off the company’s digital factory production line and is advancing toward its planned 2023 launch.

The agile LM 400 spacecraft bus design enables one platform to support multiple missions, including remote sensing, communications, imaging, radar and persistent surveillance. Lockheed Martin invested in common satellite designs to support demand for more proliferated systems, high-rate production and affordable solutions. The LM 400 is scalable and versatile starting at the size of the average home refrigerator, with capability to grow for higher power and larger payloads and packaged to enable multiple satellites per launch.

The LM 400 bus can operate in low, medium or geosynchronous earth orbits, providing greater flexibility than other buses in this class. The LM 400 space vehicle is compatible with a wide range of launch vehicles in a single, ride-share or multi-launch configuration.

Focused ultrasound mediated liquid biopsy in a tauopathy mouse model

Hong Chen and her collaborators found that using focused-ultrasound-mediated liquid biopsy in a mouse model released more tau proteins and another biomarker for neurodegenerative disorders into the blood than without the intervention. This noninvasive method could facilitate diagnosis of neurodegenerative disorders.
Illustration Credit: Chen lab

Several progressive neurodegenerative disorders, including Alzheimer’s disease, are defined by having tau proteins in the brain. Researchers are seeking to identify the mechanisms behind these tau proteins to develop treatments, however, their efforts to detect biomarkers in blood has been hampered by the protective blood-brain barrier.

At Washington University in St. Louis, new research from the lab of Hong Chen, associate professor of biomedical engineering in the McKelvey School of Engineering and of radiation oncology in the School of Medicine, and collaborators found that using focused-ultrasound-mediated liquid biopsy in a mouse model released more tau proteins and another biomarker into the blood than without the intervention. This noninvasive method could facilitate diagnosis of neurodegenerative disorders, the researchers said.

The method, known as sonobiopsy, uses focused ultrasound to target a precise location in the brain. Once located, the researchers inject microbubbles into the blood that travel to the ultrasound-targeted tissue and pulsate, which safely opens the blood-brain barrier. The temporary openings allow biomarkers, such as tau proteins and neurofilament light chain protein (NfL), both indicative of neurodegenerative disorders, to pass through the blood-brain barrier and release into the blood.

Probe can measure both cell stiffness and traction, researchers report

Professor Ning Wang, front right, is joined by researchers, from left, Fazlur Rashid, Kshitij Amar and Parth Bhala.
Photo Credit: Fred Zwicky

Scientists have developed a tiny mechanical probe that can measure the inherent stiffness of cells and tissues as well as the internal forces the cells generate and exert on one another. Their new “magnetic microrobot” is the first such probe to be able to quantify both properties, the researchers report, and will aid in understanding cellular processes associated with development and disease.

They detail their findings in the journal Science Robotics.

“Living cells generate forces through protein interactions, and it’s very hard to measure these forces,” said Ning Wang, a professor of mechanical science and engineering at the University of Illinois Urbana-Champaign who led the research. “Most probes can either measure the forces actively generated by the tissues and cells themselves, a trait we call traction, or they can measure their stiffness – but not both.”

To measure cell stiffness, researchers need a relatively rigid probe that can compress, stretch or twist the tissues and quantify how robustly they resist. But to measure the cells’ own internally generated contractions or expansions, a probe must be relatively soft and supple.

Like other scientists, Wang and his colleagues had already developed probes to measure each of these qualities individually. But he said he wanted to develop a more universal probe that could tackle both at once. Such a probe would allow a better understanding of how these properties influence diseases like arteriosclerosis or cancer, or how an embryo develops, for example.

Fish sensory organ key to improving navigational skills of underwater robots

Yellow blaze African cichlid
Photo Credit: Sarah Page

Scientists, led by the University of Bristol, have been studying a fish sensory organ to understand cues for collective behavior which could be employed on underwater robots.

This work was centered around the lateral line sensing organ in African cichlid fish, but found in almost all fish species, that enables them to sense and interpret water pressures around them with enough acuity to detect external influences such as neighboring fish, changes in water flow, predators and obstacles.

The lateral line system as a whole is distributed over the head, trunk and tail of the fish. It is comprised of mechanoreceptors (neuromasts) that are either within subdermal channels or on the surface of the skin.

Lead author Elliott Scott of the University of Bristol’s Department of Engineering Mathematics explained: “We were attempting to find out if the different areas of the lateral line - the lateral line on the head versus the lateral line on the body, or the different types of lateral line sensory units such as those on the skin, versus those under it, play different roles in how the fish is able to sense its environment through environmental pressure readings.

Plasma thrusters used on satellites could be much more powerful

The chamber where prof. Benjamin Jorns’ team tests the new Hall plasma thruster at the PEPL lab on the University of Michigan’s North Campus.
Photo Credit: Marcin Szczepanski/Lead Multimedia Storyteller, University of Michigan College of Engineering

It was believed that running more propellant through a Hall thruster would wreck its efficiency, but new experiments suggest they might power a crewed mission to Mars

It was believed that Hall thrusters, an efficient kind of electric propulsion widely used in orbit, need to be large to produce a lot of thrust. Now, a new study from the University of Michigan suggests that smaller Hall thrusters can generate much more thrust—potentially making them candidates for interplanetary missions.

“People had previously thought that you could only push a certain amount of current through a thruster area, which in turn translates directly into how much force or thrust you can generate per unit area,” said Benjamin Jorns, U-M associate professor of aerospace engineering who led the new Hall thruster study to be presented at the AIAA SciTech Forum in National Harbor, Maryland, today.

Soft robots harness viscous fluids for complex motions

Soft Robot
Video Credit: Courtesy of Collective Embodied Intelligence Lab | Cornell University 

One of the virtues of untethered soft robots is their ability to mechanically adapt to their surroundings and tasks, making them ideal for a range of roles, from tightening bolts in a factory to conducting deep-sea exploration. Now they are poised to become even more agile and controlled.

A team of researchers led by Kirstin Petersen, assistant professor of electrical and computer engineering in the College of Engineering, designed a new – and surprisingly simple – system of fluid-driven actuators that enable soft robots to achieve more complex motions. The researchers accomplished this by taking advantage of the very thing – viscosity – that had previously stymied the movement of such robots.

The team’s paper, “Harnessing Nonuniform Pressure Distributions in Soft Robotic Actuators,” published Jan. 20 in Advanced Intelligent Systems. The paper’s lead author is postdoctoral researcher Yoav Matia.

New Tool Uses Ultrasound ‘Tornado’ to Break Down Blood Clots

Ultrasonic Tornado
Illustration Credit: Xiaoning Jiang / Courtesy of North Carolina State University

Researchers have developed a new tool and technique that uses “vortex ultrasound” – a sort of ultrasonic tornado – to break down blood clots in the brain. The new approach worked more quickly than existing techniques to eliminate clots formed in an in vitro model of cerebral venous sinus thrombosis (CVST).

“Our previous work looked at various techniques that use ultrasound to eliminate blood clots using what are essentially forward-facing waves,” says Xiaoning Jiang, co-corresponding author of a paper on the work. “Our new work uses vortex ultrasound, where the ultrasound waves have a helical wavefront.

“In other words, the ultrasound is swirling as it moves forward,” says Jiang, who is the Dean F. Duncan Professor of Mechanical and Aerospace Engineering at North Carolina State University. “Based on our in vitro testing, this approach eliminates blood clots more quickly than existing techniques, largely because of the shear stress induced by the vortex wave.”

“The fact that our new technique works quickly is important, because CVST clots increase pressure on blood vessels in the brain,” says Chengzhi Shi, co-corresponding author of the work and an assistant professor of mechanical engineering at Georgia Tech. “This increases the risk of a hemorrhage in the brain, which can be catastrophic for patients.

Stanford Medicine researchers measure thousands of molecules from a single drop of blood

A single drop of blood can yield measurements for thousands of proteins, fats and other biomarkers, researchers at Stanford Medicine found.
Photo Credit: PublicDomainPictures

Researchers at Stanford Medicine have shown they can measure thousands of molecules — some of which are signals of health — from a single drop of blood.

The new approach combines a microsampling device — a tool used to self-administer a finger prick — with “multi-omics” technologies, which simultaneously analyze a vast array of proteins, fats, by-products of metabolism and inflammatory markers.

“Even more importantly, we’ve shown you can collect the blood drop at home and mail it into the lab,” said Michael Snyder, PhD, director of the Center for Genomics and Personalized Medicine and senior author on the research, which was published in Nature Biomedical Engineering on Jan. 19.

Unlike finger-prick testing for diabetes, which measures a single type of molecule (glucose), multi-omics microsampling gives data about thousands of different molecules at once.

The research sounds similar to a well-known approach promoted in the past for testing a single drop of blood, but there are important differences: While the earlier approach was based on replicating existing diagnostic tests, multi-omic microsampling uses a different type of data analysis based on a technology called mass spectrometry, which sorts molecules based on their mass and electronic charge. In addition, the data analysis is performed in a lab, not in a portable box.

Removing water, stains, contaminants with hydrogel beads

Snapshots of the hydrogel bead impacting the droplet causing the droplet to lift off the surface.
Photo Credit: Courtesy of University of Hawaiʻi

There may be a more efficient future for water repellent materials and methods thanks to new research from the University of Hawaiʻi at Mānoa College of Engineering. Associate Professor John S. Allen III and an international team of researchers have discovered a method to remove liquid from non-stick surfaces using hydrogel beads, a material similar to gel cap medications.

“Ever want to remove a puddle completely without touching it? How about removing staining coffee off your clothes? Do you know that all the dangerous contaminants are off the surface? All these might be facilitated with low-cost hydrogel beads in the future,” Allen explained.

For a variety of everyday and industrial waterproof/water resistant objects, it is important to reduce the contact time of an impacting water or liquid drop with the surface. Many people are familiar with water repellent coating on buildings and on clothing. Repellants are also used to mitigate icing on a plane, as bouncing droplets are less likely to have time to freeze.

Getting under your skin for better health

UC College of Engineering and Applied Science professor Jason Heikenfeld in his Novel Devices Lab.
 Photo Credit: Andrew Higley/UC Marketing + Brand

The next frontier of continuous health monitoring could be skin deep.

Biomedical engineers at the University of Cincinnati say interstitial fluid, the watery fluid found between and around cells, tissues or organs in the body, could provide an excellent medium for early disease diagnosis or long-term health monitoring.

In a paper published in the journal Nature Biomedical Engineering, they outlined the potential advantages and technological challenges of using interstitial fluid.

“Why we see it as a valuable diagnostic fluid is continuous access. With blood, you can’t easily take continuous readings,” said UC doctoral graduate Mark Friedel, co-lead author of the study.

“Can you imagine going about your day with a needle stuck in your vein all day? So, we need other tools.”

Microelectronics give researchers a remote control for biological robots

Remotely controlled miniature biological robots have many potential applications in medicine, sensing and environmental monitoring.   
Photo Credit: Yongdeok Kim

First, they walked. Then, they saw the light. Now, miniature biological robots have gained a new trick: remote control.

The hybrid “eBiobots” are the first to combine soft materials, living muscle and microelectronics, said researchers at the University of Illinois Urbana-Champaign, Northwestern University and collaborating institutions. They described their centimeter-scale biological machines in the journal Science Robotics.

“Integrating microelectronics allows the merger of the biological world and the electronics world, both with many advantages of their own, to now produce these electronic biobots and machines that could be useful for many medical, sensing and environmental applications in the future,” said study co-leader Rashid Bashir, an Illinois professor of bioengineering and dean of the Grainger College of Engineering.

Cyborg Cells Could Be Tools for Health and Environment

UC Davis biomedical engineers have created semi-living “cyborg cells” that have many of the capabilities of living cells but are unable to divide and grow. The cells could have applications in medicine and environmental cleanup.
Illustration Credit: Cheemeng Tan, UC Davis.

Biomedical engineers at the University of California, Davis, have created semi-living “cyborg cells.” Retaining the capabilities of living cells, but unable to replicate, the cyborg cells could have a wide range of applications, from producing therapeutic drugs to cleaning up pollution. The work was published in Advanced Science.

Synthetic biology aims to engineer cells that can carry out novel functions. There are essentially two approaches in use, said Cheemeng Tan, associate professor of biomedical engineering at UC Davis and senior author on the paper. One is to take a living bacterial cell and remodel its DNA with new genes that give it new functions. The other is to create an artificial cell from scratch, with a synthetic membrane and biomolecules.

The first approach, an engineered living cell, has great flexibility but is also able to reproduce itself, which may not be desirable. A completely artificial cell cannot reproduce but is less complex and only capable of a limited range of tasks.

Wearable, Printable, Shapeable Sensors Detect Pathogens and Toxins in the Environment

“Using the sensor, we can pick up trace levels of airborne SARS-CoV-2, or we can imagine modifying it to adapt to whatever the next public health threat might be,” Omenetto said. Here, a sensor is embedded on a drone.
Photo Credit: Courtesy of Silklab

Researchers at Tufts School of Engineering have developed a way to detect bacteria, toxins, and dangerous chemicals in the environment using a biopolymer sensor that can be printed like ink on a wide range of materials, including wearable items such as gloves, masks, or everyday clothing.

Using an enzyme similar to that found in fireflies, the sensor glows when it detects these otherwise invisible threats. The new technology is described in the journal Advanced Materials.

The biopolymer sensor, which is based on computationally designed proteins and silk fibroin extracted from the cocoons of the silk moth Bombyx Mori, can also be embedded in films, sponges, and filters, or molded like plastic to sample and detect airborne and waterborne dangers, or used to signal infections or even cancer in our bodies.

The researchers demonstrated how the sensor emits light within minutes as it detects the SARS-CoV-2 virus that causes COVID, anti-hepatitis B virus antibodies, the food-borne toxin botulinum neurotoxin B, or human epidermal growth factor receptor 2 (HER2), an indicator of the presence of breast cancer.

Controlled, localized delivery of blood thinner may improve blood clot treatment

Co-authors Atip Lawanprasert (left), doctoral student in biomedical engineering, Sopida Pimcharoen (center), undergraduate student in biomedical engineering and Scott Medina (right), Penn State associate professor of biomedical engineering, analyze results related to their study of combining the anticoagulant heparin with peptide to slow down the medication's delivery at the site of a blood clot.
Photo Credit: Jeff Xu / Pennsylvania State University

Heparin has long been used as a blood thinner, or anticoagulant, for patients with blood clotting disorders or after surgery to prevent complications. But the medication remains difficult to dose correctly, potentially leading to overdosing or underdosing.

A team of Penn State researchers combined heparin with a protein fragment, peptide, to slow down the release of the drug and convey the medication directly to the site of a clot. They published their findings in the journal Small.

“We wanted to develop a material that can gradually deliver heparin over time rather than the current iteration that gets cleared from the body in a couple of hours,” said corresponding author Scott Medina, Penn State associate professor of biomedical engineering. “We also wanted to deliver the drug through the skin instead of through an IV.”

When mixed, positively charged peptides and negatively charged heparin bind to create a nanogranular paste that can be injected under the skin, forming a cache of material that is then diffused in the circulatory system and travels to blood clots when they appear. The turbulent flow of fluid near a blood clot triggers the two materials to separate, allowing heparin to begin its anticoagulating action.

UCR scientists develop method to turn plastic waste into potentially valuable soil additive

Recent rain storms washed plastic waste into a creek bed in Riverside's Fairmount Park.
Photo Credit: David Danelski/UCR

University of California, Riverside, scientists have moved a step closer to finding a use for the hundreds of millions of tons of plastic waste produced every year that often winds up clogging streams and rivers and polluting our oceans.

In a recent study, Kandis Leslie Abdul-Aziz, a UCR assistant professor of chemical and environmental engineering, and her colleagues detailed a method to convert plastic waste into a highly porous form of charcoal or char that has a whopping surface area of about 400 square meters per gram of mass.

Such charcoal captures carbon and could potentially be added to soil to improve soil water retention and aeration of farmlands. It could also fertilize the soil as it naturally breaks down. Abdul-Aziz, however, cautioned that more work needs to be done to substantiate the utility of such char in agriculture.

The plastic-to-char process was developed at UC Riverside’s Marlan and Rosemary Bourns College of Engineering. It involved mixing one of two common types of plastic with corn waste — the leftover stalks, leaves, husks, and cobs — collectively known as corn stover. The mix was then cooked with highly compressed hot water, a process known as hydrothermal carbonization.

Self-powered, printable smart sensors created from emerging semiconductors could mean cheaper, greener Internet of Things

Simon Fraser University professor Vincenzo Pecunia
Photo Credit: Courtesy of Simon Fraser University

Creating smart sensors to embed in our everyday objects and environments for the Internet of Things (IoT) would vastly improve daily life—but requires trillions of such small devices. Simon Fraser University professor Vincenzo Pecunia believes that emerging alternative semiconductors that are printable, low-cost and eco-friendly could lead the way to a cheaper and more sustainable IoT.

Leading a multinational team of top experts in various areas of printable electronics, Pecunia has identified key priorities and promising avenues for printable electronics to enable self-powered, eco-friendly smart sensors. His forward-looking insights are outlined in his paper published on Dec. 28 in Nature Electronics.

“Equipping everyday objects and environments with intelligence via smart sensors would allow us to make more informed decisions as we go about in our daily lives,” says Pecunia. “Conventional semiconductor technologies require complex, energy-intensity, and expensive processing, but printable semiconductors can deliver electronics with a much lower carbon footprint and cost, since they can be processed by printing or coating, which require much lower energy and materials consumption.”