Engineered Bacteria Cross the Blood-Brain Barrier for Drug Delivery

Hello and welcome to our February 11th 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 - Scientists Develop Chiral Semiconductor Films with Exceptional Light-Bending Properties, and more.

• Materials - New Membrane Technology Enables Efficient Recycling of Refrigerants, and more.

• Biotechnology - Engineered Bacteria Cross the Blood-Brain Barrier for Drug Delivery.

• Engineering & Technology - Turning Vehicle Exhaust Heat into Electricity, and more.

• Astronomy & Space - Astronomers Study Newly Discovered Supernova SN 2024jlf.

• Health & Medicine - New Light-Sensitive Chemicals Eradicate Aggressive Cancer in Mice, and more.

• Neuroscience -AI Sheds Light on How the Brain Learns Relationships, and more.

• Environment - Greenland Ice Sheet Nears Irreversible Tipping Point, and more.

• Nature - New Study Reveals Biofluorescence in Birds-of-Paradise, Deep-Sea Shrimp Evolved Unique Vision to Navigate Bioluminescent World, and more.

Until Tomorrow,

~The STEAM Digest

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SCIENCE

Cornell Scientists Develop Chiral Semiconductor Films with Exceptional Light-Bending Properties: Cornell researchers have developed a novel technique to create chiral semiconductor materials capable of twisting light, a breakthrough that could revolutionize optical technologies like displays, sensors, and quantum computing. Using magic-sized clusters of cadmium-based semiconductors, the team employed meniscus-guided evaporation to twist these nanoparticles into helical structures, forming films with an unprecedented light-matter response nearly 100 times stronger than previously reported inorganic materials. These films exhibit circular dichroism, meaning they absorb left- and right-polarized light differently, similar to how DNA and biological structures function. The discovery has potential applications in holographic 3D displays, non-invasive medical diagnostics, and ultra-low-power devices. Future work will explore scaling the method for industrial applications, expanding its use to quantum dots and nanoplatelets to further advance nanotechnology and optical engineering.

Rice University Scientists Develop Water-Based Chemical Reactors for Sustainable Chemistry: Researchers at Rice University have developed a sustainable method for performing chemical reactions in water, eliminating the need for toxic solvents. By designing metal complex surfactants (MeCSs) that self-assemble into nanoscale micelles, they created tiny reaction vessels capable of driving light-powered chemical processes. These micelles, as small as 5–6 nanometers, enable reactions with water-insoluble materials, making them a greener alternative for industries like pharmaceuticals and materials science. The system is reusable, cost-effective, and environmentally friendly, offering a breakthrough in sustainable chemistry.

MATERIALS

New Membrane Technology Enables Efficient Recycling of Refrigerants: Researchers at the University of Kansas have developed a membrane-based technology to efficiently separate and recycle refrigerants, reducing harmful greenhouse gas emissions. Unlike traditional distillation methods, which struggle with complex refrigerant mixtures, this new approach uses amorphous fluorinated polymer membranes to selectively filter gases for effective purification. The innovation addresses the urgent need for refrigerant recovery, as substances like HFC-134a have a global warming potential 1,430 times that of CO₂, with 90% of leaks occurring at end-of-life disposal. Developed by Abby Harders during her Ph.D., the technology is now being translated into industry through Icorium Engineering, offering a scalable solution for sustainable refrigerant reuse.

Self-Optimizing Catalyst Boosts CO₂ Conversion Efficiency: Researchers have developed a sustainable electrocatalyst that improves its efficiency over time while converting carbon dioxide (CO₂) into valuable formate. Made of tin microparticles on nanotextured carbon, the catalyst facilitates electron transfer, a key step in CO₂ reduction. Unlike conventional catalysts that degrade with use, this system enhances its performance, with electrical current increasing continuously over 48 hours. The self-optimization occurs as tin microparticles break down into smaller, more reactive nanoparticles, improving electron transport and increasing active tin centers tenfold. This breakthrough offers a scalable, low-energy alternative for CO₂ utilization, supporting net-zero emission goals while advancing green chemical production using earth-abundant materials like tin and carbon.

Superconducting Nanowires Repurposed for High-Energy Particle Detection: Researchers at Argonne National Laboratory have successfully adapted superconducting nanowire single-photon detectors (SNSPDs) to detect high-energy protons for the first time. Originally designed for photon detection, SNSPDs demonstrated high sensitivity and precision in experiments at Fermilab, particularly with wire widths around 250 nanometers. These detectors also function well in high magnetic fields, making them suitable for use in particle accelerators like the upcoming Electron-Ion Collider (EIC) at Brookhaven National Laboratory. This breakthrough expands the applications of SNSPDs beyond quantum science, enhancing future nuclear and particle physics research.

BIOTECHNOLOGY

Engineered Bacteria Cross the Blood-Brain Barrier for Drug Delivery: Researchers have developed a novel method to bypass the blood-brain barrier using engineered Lactobacillus plantarum. This modified bacterium, applied intranasally, delivers appetite-regulating hormones directly to the brain via the olfactory epithelium, allowing therapeutic molecules to diffuse into adjacent brain regions. In mouse studies, this approach led to reduced body weight gain, lower food consumption, and improved glucose tolerance in high-fat diet models. Unlike traditional intranasal therapies, which suffer from rapid clearance, the bacterial method provided a sustained drug presence in the nasal passage. This research demonstrates potential for treating neurological conditions such as Parkinson’s, Alzheimer’s, and brain cancer by enabling noninvasive, targeted drug delivery to the brain. Future studies will focus on dosage optimization and safety, paving the way for breakthrough treatments that overcome the barrier to brain-targeted therapy.

ENGINEERING & TECHNOLOGY

Turning Vehicle Exhaust Heat into Electricity: Researchers have developed a thermoelectric generator that converts waste heat from vehicle exhaust into electricity, potentially improving fuel efficiency and reducing carbon dioxide emissions. The system, designed by Wenjie Li and Bed Poudel, uses a bismuth-telluride semiconductor and heat exchangers to capture exhaust heat, while a heatsink enhances the temperature difference for greater electrical output. The prototype generated 40 watts—enough to power a lightbulb—and simulations showed higher outputs in high-speed environments, reaching 56 W for cars and 146 W for helicopters. Unlike previous thermoelectric devices, this system integrates directly into exhaust outlets without additional cooling systems, making it a practical solution for waste-heat recovery in cars, helicopters, and UAVs. This breakthrough offers a step toward cleaner energy in transportation.

Soft Robot Uses Snap-Through Motion for Advanced Movement: Researchers have developed a soft robot that can crawl, climb cables, and rapidly change shape using a single air input. Unlike previous soft robots requiring complex controls, this new design uses a snap-through mechanism, similar to a Venus flytrap, to shift between movements seamlessly. The robot features a Snap Inflatable Modular Metastructure (SIMM) that allows it to deform smoothly and then suddenly snap into a new shape. Demonstrations showed it could crawl like a worm, grip and ascend cables, and change direction instantly. This advancement could lead to rescue robots capable of navigating debris, medical robots for internal procedures, and deployable structures that change shape on demand.

Privacy-Preserving Sensors Revolutionize Smart Buildings and Senior Care: Startup Butlr, founded by two former MIT Media Lab researchers, has developed privacy-preserving thermal sensors that track movement without cameras. These sensors help optimize office spaces, reduce energy consumption, and enhance senior care by detecting falls and monitoring mobility in nursing homes and assisted living facilities. Unlike traditional surveillance, Butlr’s system captures only heat-based body outlines, ensuring user privacy while providing valuable real-time data. Their technology has already been deployed in corporate offices (including Verizon, Netflix, and Microsoft) and healthcare settings, where it aids in fall detection and early signs of cognitive decline. Collaborating with Harvard Medical School and UMass Amherst, Butlr aims to expand its applications in aging and Alzheimer's care. The company envisions AI-driven responsive architecture, where buildings adapt dynamically to occupants' needs, offering a smarter, safer, and more sustainable future.

SPLITTER: A Revolutionary Robotic System for Planetary Exploration: Researchers have developed SPLITTER (Space and Planetary Limbed Intelligent Tether Technology Exploration Robot), a multi-robot system designed for planetary exploration. The system consists of two quadrupedal robots connected by a tether, allowing for dynamic, successive jumping in low-gravity environments such as the Moon or asteroids. Unlike traditional rovers, which are heavy and slow, or aerial drones, which struggle in atmospheres lacking air, SPLITTER leverages inertial morphing and a Model Predictive Controller (MPC) to maintain mid-air stability. This design offers advantages in mass efficiency and agility, eliminating the need for reaction wheels or gas thrusters. Additionally, the tether allows for innovative exploration strategies, such as one robot descending into a crater while the other remains anchored. The researchers envision deploying SPLITTER in robot swarms to explore vast, unstructured environments, with potential applications extending to spacecraft stabilization. Future developments will focus on refining the hardware and simulation testing to enhance its real-world viability.

ASTRONOMY & SPACE

Astronomers Study Newly Discovered Supernova SN 2024jlf: An international team of astronomers has investigated SN 2024jlf, a recently detected Type II supernova, providing new insights into its evolution and progenitor star. Discovered on May 28, 2024, by the Zwicky Transient Facility (ZTF), the supernova exploded in the edge-on spiral galaxy NGC 5690. Early observations revealed a blue continuum with flash ionization features, indicating a young core-collapse supernova. Analysis of its light curve suggests that SN 2024jlf initially brightened faster than 90% of known Type II supernovae before settling into a typical Type IIP plateau phase lasting 85 days. The study estimates that SN 2024jlf originated from a red supergiant star with a mass of ~10 solar masses, an explosion energy of ~1.5 sexdecillion erg, and a mass-loss rate between 0.0001–0.001 solar masses per year. Researchers highlight the importance of automated follow-up observations, such as those using the BTSbot machine learning model, in advancing our understanding of core-collapse supernovae.

HEALTH & MEDICINE

Potassium-Enriched Salt Linked to Lower Stroke Recurrence and Mortality: A large-scale clinical trial in rural northern China found that replacing regular salt with a 25% potassium chloride substitute significantly reduced recurrent strokes and mortality among stroke survivors. Conducted as part of the Salt Substitute and Stroke Study (SSaSS), researchers analyzed data from 15,249 participants and observed a 14% decrease in recurrent strokes, with hemorrhagic stroke risk reduced by 30% and stroke-related deaths lowered by 21%. The study, which monitored blood pressure and sodium/potassium excretion, showed that potassium-enriched salt lowered systolic blood pressure without increasing the risk of hyperkalemia. These findings highlight salt substitution as a safe, cost-effective strategy for reducing stroke recurrence and mortality, particularly in high-risk regions with limited healthcare access.

New Light-Sensitive Chemicals Eradicate Aggressive Cancer in Mice: Scientists have developed cyanine-carborane salts, a breakthrough in photodynamic therapy (PDT) that completely eradicated metastatic breast cancer tumors in mice. Unlike traditional PDT, which has limitations like prolonged light sensitivity and poor tissue penetration, these new chemicals target only cancer cells, flush out of the body quickly, and can be activated by near-infrared light, allowing deeper tissue treatment. The salts exploit OATP proteins, which are overexpressed in tumors, enabling precise targeting without harming healthy tissue. Researchers believe this innovation could expand cancer treatment options and pave the way for safer, more effective therapies.

Mutation in Vimentin Protein Increases Breast Cancer Aggressiveness: Researchers have identified a mutation in the vimentin protein that makes breast cancer more aggressive. By modifying an amino acid at position 328 (cysteine to serine), the mutation disrupted vimentin’s role in the cell’s structural network, leading to increased cell growth, migration, and invasion while reducing adhesion. RNA sequencing revealed that the mutation was linked to XIST, a non-coding RNA involved in cancer progression. In mice models, breast cancer cells with mutant vimentin grew independently of estrogen and exhibited cancer stem cell-like behavior, marked by high expression of CD56 and CD20, traits associated with tumor progression and therapy resistance. These findings provide new insights into breast cancer development and suggest that vimentin mutations could serve as biomarkers for aggressive cancer types, paving the way for early detection and targeted treatments.

NEUROSCIENCE

AI Sheds Light on How the Brain Learns Relationships: Researchers have used brain-inspired artificial neural networks to uncover potential biological mechanisms behind relational learning, the ability to recognize relationships between objects or events. The study explored transitive inference—a cognitive skill where, if A > B and B > C, then A > C—which humans and certain animals naturally develop. The researchers augmented neural networks with synaptic plasticity, allowing them to self-learn relationships, similar to how primates quickly update knowledge. Their models mimicked experimentally observed behaviors, revealing two distinct learning mechanisms: a basic one for general ordering and a more advanced one for knowledge reassembly, a trait found in primates but not rodents or pigeons. This breakthrough not only enhances understanding of cognitive learning in the brain but also highlights AI’s role in studying biological intelligence, potentially leading to new insights into human cognition and decision-making.

Study Confirms Vagus Nerve's Role in Gut Microbiome-Brain Communication: Researchers at UCLA's Hsiao Lab have provided direct evidence that the vagus nerve plays a crucial role in gut microbiome-brain communication, addressing a longstanding gap in scientific understanding. The study found that germ-free mice (raised without gut bacteria) exhibited reduced vagal nerve activity, which was restored after introducing gut bacteria from normal mice. Similarly, using antibiotics to disrupt the microbiome in normal mice lowered vagal activity, but it was restored with microbiota-rich intestinal fluids, confirming the microbiome's role in neural signaling. The researchers also identified specific metabolites, including short-chain fatty acids and bile acids, that activate distinct vagus nerve neurons, linking the gut to brainstem activity. This discovery enhances understanding of the gut-brain axis and may pave the way for new treatments for neurological and gastrointestinal disorders.

Tiny Eye Movements Enhance Visual Acuity: New research reveals that fixational eye movements—tiny, involuntary eye movements—sharpen rather than blur our vision. Using advanced eye-tracking technology and computational models, scientists discovered that these movements refresh visual receptors, optimizing the way the retina processes information. The study found that humans naturally maintain these movements within an ideal range, enhancing visual clarity and adapting to object size. These insights could help in developing treatments for vision disorders and improving our understanding of visual processing.

ENVIRONMENT

Greenland Ice Sheet Nears Irreversible Tipping Point: A new study warns that Greenland’s ice sheet is approaching a critical tipping point, beyond which it may never recover, leading to complete melting. Researchers at Norway's Bjerknes Centre for Climate Research found that if 230 gigatons of ice are lost in a single year—equivalent to 60% of pre-industrial surface mass balance—the ice sheet could enter a phase of irreversible decline, lasting between 8,000 and 40,000 years. This threshold corresponds to a global temperature rise of 3.4°C, far beyond the 1.5°C limit set by the Paris Agreement, which was already breached in 2024. Key factors driving ice loss include surface melting outweighing glacial isostatic adjustment, albedo feedback loops, and the retreat of the western coastal ice margin, which could determine the ice sheet's fate. While some high-elevation areas in the west may help stabilize the ice sheet, researchers emphasize that urgent climate action is needed to prevent further warming and avoid catastrophic sea level rise of up to 7 meters if the ice sheet fully melts.

Microplastics Increase Toxic Chemical Absorption in Plants and Humans: Researchers at Rutgers Health have found that micro- and nanoscale plastics significantly increase the absorption of toxic chemicals in both plants and human intestinal cells, raising concerns about food safety. In studies (1,2) lettuce exposed to plastic particles absorbed more arsenic and pesticides, while human intestinal cells showed a six-fold increase in arsenic absorption when exposed to nanoscale plastics. This research highlights a dangerous contamination cycle, where plastic pollution makes both plants and humans absorb more toxins, increasing potential health risks. Scientists stress the need for reducing plastic waste and developing biodegradable alternatives to prevent further contamination.

Blowing Dust Costs the U.S. $154 Billion Annually, Study Finds: A new study estimates that wind erosion and blowing dust cost the U.S. approximately $154 billion per year across multiple sectors, including health care, transportation, agriculture, renewable energy, and households. Dust-related health issues, such as Valley Fever, account for $2.7 billion in medical costs annually, while dust storms cause at least $250 million in traffic accidents. Agricultural losses due to soil degradation reach $10 billion, and dust reduces the efficiency of solar and wind energy systems, costing around $4 billion. Additionally, household damage and landscaping losses total $40 billion annually. The researchers stress that dust mitigation efforts, such as no-till farming and conservation agriculture, could significantly reduce economic losses and prevent another Dust Bowl-like disaster. With dust activity increasing in recent decades, they urge proactive measures to curb its growing financial and environmental impact.

NATURE

New Study Reveals Biofluorescence in Birds-of-Paradise: Researchers from the American Museum of Natural History and the University of Nebraska-Lincoln have discovered widespread biofluorescence in 37 of the 45 known birds-of-paradise species. This glowing effect, visible under ultraviolet and blue light, is especially prominent in males, enhancing their mating displays and social hierarchy. Using specialized lighting techniques, the scientists found that biofluorescence appears in key areas such as the bill, feet, feathers, and inner mouth, which are highlighted during courtship rituals. The study suggests that birds-of-paradise, which inhabit forests near the equator, can perceive these glowing signals, potentially giving them an evolutionary advantage in mate selection. This breakthrough adds to previous biofluorescence research across the animal kingdom and offers new insights into the complex visual communication of these vibrant birds.

Deep-Sea Shrimp Evolved Unique Vision to Navigate Bioluminescent World: New research reveals that light plays a key role in the evolution of deep-sea shrimp vision. The study focused on Oplophoroidea shrimp, which migrate across vast ocean depths and live in environments illuminated only by bioluminescence. Researchers found that these shrimp possess a diverse array of opsin proteins, which help them detect different light sources, including their own glow and that of other animals. Shrimp that migrate to shallower waters, where more light is available, have evolved a greater variety of these proteins, allowing them to perceive a broader range of colors. This discovery provides insight into how visual systems evolved in light-limited environments and how deep-sea animals use bioluminescence to navigate, communicate, and avoid predators. The findings pave the way for further research on bioluminescence and visual adaptation in deep-sea species.