MIT Team Develops Light-Responsive Artificial Muscles That Move in Multiple Directions

Hello and welcome to our March 17, 2025 edition. The STEAM Digest is a curated newsletter that brings you the latest news in science, technology, engineering, arts, and mathematics.

In today’s edition:

• Science - New Scaling Law Predicts Fracture Strength of Stretchable Network Materials.

• Materials - Magnetically Guided Microalgae Microrobots Offer New Hope for Targeted Drug Delivery, and more.

• Engineering & Technology - MIT Team Develops Light-Responsive Artificial Muscles That Move in Multiple Directions, and more.

• Health & Medicine - Dry Air Poses Growing Threat to Respiratory Health in a Warming Climate, Study Finds, and more.

• Neuroscience - Researchers Discover Brain Network That Enables Voluntary Stopping of Speech, and more.

• Nature - Gorillas Show Signs of Self-Awareness in New “Body as Obstacle” Test, and more.

• Other Sciences & The Arts - Mathematician Susanna Heikkilä Helps Solve Decades-Old Geometry Problem, and more.

Until Tomorrow,

~The STEAM Digest

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SCIENCE

New Scaling Law Predicts Fracture Strength of Stretchable Network Materials:
A team of U.S. researchers has developed a universal scaling law to accurately calculate the intrinsic fracture energy (IFE) of stretchable, networked materials—a key measure of their strength and resistance to tearing. The study shows that IFE depends solely on three factors: the force required to break an individual strand, its stretch length at breaking, and the number of strands per unit area. This law applies across various materials and network structures, from nanometer to meter scales and in both 2D and 3D geometries. Using both experimental and computational methods—including hydrogels with diamond cubic lattice networks and large-scale simulations—the team validated the model's broad applicability. This breakthrough offers engineers a powerful tool to design tough, durable materials for applications in soft robotics, tissue engineering, and aerospace structures, without relying solely on trial-and-error approaches.

MATERIALS

Magnetically Guided Microalgae Microrobots Offer New Hope for Targeted Drug Delivery: Researchers have developed biohybrid micro swimmers—microalgae coated with magnetic nanoparticles—that can be precisely steered through narrow, viscous environments, such as those found in human tissues. The study shows that despite being magnetized, the algae maintained their natural swimming ability, reaching speeds of 115 micrometers per second, or about 12 body lengths per second. Using external magnetic fields, scientists successfully guided the algae through confined microchannels, including those simulating mucus-like viscosity. The magnetic control prevented the algae from getting stuck, offering promising applications in targeted drug delivery and minimally invasive biomedical procedures. The innovation combines biocompatibility with mechanical precision, paving the way for future microrobotic therapies.

Twisted 2D Materials Unlock New Quantum Potential for Future Technologies:
Researchers have discovered that twisting two atom-thin layers of molybdenum diselenide at high angles (up to 40°) produces excitons—artificial atoms capable of storing quantum information. The study reveals that these "dark excitons", which normally don’t interact with light, can become optically active through this twisting technique, allowing precise quantum control while remaining protected from environmental noise. Unlike traditional moiré superlattices that use small "magic angles," this breakthrough shows that large-angle twists can also generate useful quantum optical properties. The team envisions future applications in quantum memory, lasers, and quantum networks, marking a promising advance in quantum materials and computing.

Light-Driven Semiconductor Neurons Pave the Way for Neuromorphic Photonic Computing: Researchers at the International Iberian Nanotechnology Laboratory (INL) have developed a neuromorphic photonic semiconductor neuron that processes optical information through self-sustained oscillations. The study demonstrates the use of light-induced negative differential resistance (NDR) in gallium arsenide micropillar resonant tunneling diodes (RTDs) to replicate the oscillatory behavior of biological neurons. These devices integrate both sensory reception and rhythmic burst firing within a single miniaturized component, eliminating the need for external circuitry. The technology offers a promising step toward energy-efficient, high-speed neuromorphic computing for artificial vision and edge processing applications.

BIOTECHNOLOGY

Engineered E. coli Bacteria Used to Create Biodegradable Plastic Alternative:
A new study reports the successful engineering of E. coli bacteria to produce biodegradable plastics known as poly(ester amides) (PEAs). Researchers led by Sang Yup Lee developed a biosynthetic process using enzymes within E. coli to combine amino acids and hydroxy acids into PEAs. Using glucose as a feedstock, the team produced up to 55 grams per liter of polymer in bioreactors, showing potential for industrial scalability. The resulting material demonstrated thermal and mechanical properties similar to high-density polyethylene (HDPE), suggesting a viable, renewable alternative to petroleum-based plastics.

ENGINEERING & TECHNOLOGY

MIT Team Develops Light-Responsive Artificial Muscles That Move in Multiple Directions: Researchers at MIT have created a new method to grow multidirectional artificial muscle tissue, enabling more versatile movement in biohybrid robots. The study showcases a 3D-printed “stamp” technique that imprints microscopic grooves into soft hydrogels. These grooves guide real muscle cells to grow in complex patterns, mimicking natural structures like the human iris. When stimulated with light, the engineered muscle contracts in multiple directions—unlike previous artificial muscles, which moved only in one. The approach could revolutionize soft robotics, tissue engineering, and other applications requiring flexible, bio-inspired actuation.

Researchers Develop “Audible Enclaves” for Private Listening Without Headphones: A team of engineers has developed a groundbreaking audio technology that creates "audible enclaves"—localized zones where sound is heard only at specific points, allowing private listening without headphones. The study demonstrates how two ultrasonic beams intersect to generate audible sound at a precise location, inaudible to anyone nearby. Using 3D-printed acoustic metasurfaces, the beams bend and converge along a controlled path, effectively forming a virtual headset. This innovation could enable personal audio experiences in shared spaces like cars, classrooms, or public areas.

NTU Scientists Develop Solar-Powered Process to Turn Sewage Sludge into Green Hydrogen and Animal Feed: Researchers have created a solar-powered, three-step process that transforms sewage sludge into green hydrogen and single-cell protein for animal feed. The method offers a sustainable solution to the global challenges of waste management and clean energy production. By combining mechanical, chemical, and biological techniques, the process removes heavy metals, generates clean fuel, and recovers over 91% of organic carbon from sludge—significantly outperforming traditional methods. The approach cuts carbon emissions by 99.5% and showcases the potential for a circular economy, though further research is needed to scale up the technology.

HEALTH & MEDICINE

Dry Air Poses Growing Threat to Respiratory Health in a Warming Climate, Study Finds: A new study warns that exposure to dry air—expected to rise with global warming—can dehydrate the human airway and trigger inflammation. Researchers from institutions including Johns Hopkins University found that higher vapor pressure deficit (VPD), a measure of air's drying capacity, leads to thinner airway mucus and elevated inflammatory markers. Experiments in human airway cells and animal models confirmed these effects, particularly under intermittent dry air exposure. The findings suggest that rising temperatures will increase the risk of chronic respiratory conditions and highlight the need to manage airway hydration as seriously as air pollution.

Synthetic mRNA Therapy Reawakens Immune System to Combat Cancer Metastasis: A study by researchers introduces a synthetic mRNA (s-mRNA) therapy that stimulates immune cells to fight metastatic cancer, a leading cause of cancer-related deaths. The therapy uses a chemically stabilized version of IL1β-mRNA that activates natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), enhancing their tumor-killing abilities without triggering harmful inflammation. In mouse models, the treatment significantly reduced lung metastases from breast and colon cancers. It also reactivated immune cells taken from human patients, demonstrating potential for future non-toxic, immune-based cancer treatments.

Prion Protein Identified as Promising Target in Glioblastoma Treatment, Study Finds: A study led by researchers at the University of São Paulo reveals that the prion protein plays a crucial role in the recurrence of glioblastoma (GBM), a highly aggressive brain cancer. The team found that prion protein levels are elevated in glioblastoma stem cells—cells that survive traditional treatments and later regenerate the tumor. Using CRISPR-Cas9 gene editing, researchers blocked the production of the protein, reducing the stem cells' ability to invade and proliferate. The findings highlight the prion protein as a potential therapeutic target for more effective GBM treatments.

NEUROSCIENCE

Researchers Discover Brain Network That Enables Voluntary Stopping of Speech:
A groundbreaking study has identified a previously unknown brain network responsible for voluntary speech inhibition. Using high-density electrocorticography (ECoG), researchers recorded neural activity from 13 epilepsy patients performing a speech-stopping task. They found that distinct activity in the premotor frontal cortex was linked to the sudden cessation of speech—separate from the regions involved in producing speech. Further validation through brain stimulation confirmed that this premotor network can halt speech involuntarily, revealing that it plays a specialized role in inhibitory control of speech. These findings reshape previous understandings of speech-related brain activity and could have implications for treating disorders involving impaired speech control, such as stuttering or certain neurological conditions.

Sex-Specific Immune Response May Explain Why Women Experience More Chronic Pain, Study Finds: A new study reveals a potential biological explanation for why women are more likely than men to suffer from chronic pain. Focusing on neuropathic pain in rodents, the research found that both sexes transmit pain signals via pannexin 1 (Panx1) channels, but through different immune cells. In females, Panx1 activation triggers the release of leptin, a hormone linked to increased pain sensitivity. These findings shed light on sex-specific pain pathways and highlight the need for personalized treatments, especially as much past research was based primarily on male models.

Unpredictable Childhood Environments May Rewire the Brain, UC Irvine Study Finds: A comprehensive review by researchers at the University of California, Irvine reveals how early-life adversity—including unpredictable sensory experiences—can significantly affect brain development and long-term mental health. Led by Dr. Tallie Z. Baram and Matthew Birnie, the study challenges traditional views of childhood stress by emphasizing the role of environmental unpredictability alongside abuse and neglect. The authors call for a broader definition of early-life adversity and highlight how such experiences can "reprogram" the brain via molecular and circuit-level changes. Their findings suggest that refining how we assess and address early stress could improve mental health outcomes and inform more effective interventions.

NATURE

Gorillas Show Signs of Self-Awareness in New “Body as Obstacle” Test:
A new study finds that gorillas demonstrate self-awareness comparable to chimpanzees, challenging assumptions based on traditional mirror tests. The research used a novel “body-as-obstacle” test in which gorillas and chimps had to recognize that their own bodies were blocking access to food. Both species quickly moved off the box lids to retrieve the treat, suggesting a basic form of body awareness. The findings support the idea that gorillas, long considered less self-aware due to poor mirror test performance, may simply perceive and interpret mirrors differently. The study encourages scientists to use diverse testing methods to gain a fuller understanding of animal cognition and the evolution of self-awareness across species.

Hummingbird Chick Mimics Poisonous Caterpillar to Scare Off Predators, Study Finds: In a remarkable discovery, researchers have observed a white-necked jacobin hummingbird chick in Panama exhibiting Batesian mimicry—a survival tactic where a harmless species imitates a harmful one. The study describes how the chick, covered in brown fuzz, shakes its head and body in a way that mimics venomous caterpillars found in the region. This unusual behavior—never before reported in hummingbirds—appears to deter predators, as seen when a predatory wasp flew away after the chick performed the mimicry. The researchers believe the chick’s appearance and movements closely resemble stinging caterpillars that also shake when threatened. The finding expands the scope of mimicry in nature, suggesting that even vertebrates may mimic invertebrates to survive in predator-rich environments like tropical rainforests.

Native Predators Like Soldier Bugs and Mantises Could Help Control Spotted Lanternflies, Study Finds: A new study highlights the potential of native insect predators—especially spined soldier bugs and praying mantises—to reduce populations of the invasive spotted lanternfly, which has spread across at least 18 U.S. states since 2014. Researchers found these predators effectively consumed both lanternfly nymphs and adults, regardless of their host plant. The findings suggest these insects could be valuable in integrated pest management (IPM) strategies, helping reduce dependence on chemical insecticides. While not a standalone solution, conserving and encouraging these natural predators may provide a sustainable, eco-friendly approach to combat a pest that threatens vineyards, orchards, and other industries. Further field research is planned to assess real-world effectiveness.

OTHER SCIENCES & THE ARTS

Mathematician Susanna Heikkilä Helps Solve Decades-Old Geometry Problem:
Mathematician Susanna Heikkilä, in collaboration with Pekka Pankka, has resolved a major question in the field of quasiconformal geometry by classifying simply connected four-dimensional manifolds that admit quasiregular mappings from Euclidean space. Their research builds on a problem posed by Misha Gromov in 1981 and partially answered by Eden Prywes in 2019. Heikkilä and Pankka's algebraic approach shows that for a manifold to be quasiregularly elliptic, its cohomological structure must align with that of Euclidean space. This result fully classifies all such 4-manifolds, marking a significant step in geometric topology.

Flexible Skulls Helped Birds Evolve from Dinosaurs, New Study Shows: A new study reveals that cranial kinesis—the ability of birds to move parts of their skull independently—evolved alongside larger brains during the transition from dinosaurs to modern birds. Researchers from the University of Chicago and University of Missouri used CT scans and 3D models to analyze skull mechanics in modern birds, dinosaurs, and related reptiles. They found that as brain size increased in theropod dinosaurs, jaw muscles shifted, enabling more flexible, "wiggly" skulls. This gave birds evolutionary advantages like better feeding adaptability and the ability to use their beaks as versatile tools.

15-Million-Year-Old Fossil Fish with Stomach Contents and Color Pattern Discovered in Australia: In a groundbreaking discovery, scientists have identified a new fossil fish species, Ferruaspis brocksi, dating back 15 million years. Found at the McGraths Flat fossil site in New South Wales, this is Australia’s first known fossil of a freshwater smelt (order Osmeriformes), offering vital insights into ancient ecosystems and fish evolution during the Miocene epoch. Remarkably preserved, the fossil shows not only stomach contents—including phantom midge larvae—but also color patterns, reconstructed using fossilized melanosomes. One specimen even displays a parasitic juvenile mussel attached to its tail. The discovery highlights McGraths Flat as a rare Lagerstätte site with exceptionally detailed fossils, reshaping our understanding of Australia’s ancient freshwater life.