Tissue engineering offers a means to restore, maintain or replace biological tissues. But it is difficult to grow blood vessels using conventional fabrication techniques like 3D printing, as they are typically not precise enough to print fine capillaries and veins. A team of engineers from the Massachusetts Institute of Technology (MIT) has now developed a new approach to do just that, by using mechanical forces. Their blood-vessel-on-a-chip could be the first step in the scalable production of vascular networks that could then be implanted in the body to replace tissue that has been damaged by disease or injury.
The researchers, led by Ritu Raman, made their chip by filling a Petri dish with a gel containing nutrients and cell-growth factors. They then embedded a small magnet into the gel. Finally, they introduced a thin, hollow tube into the gel and coated the inside of the tube with live endothelial cells – the cells that naturally line blood vessels in the body.
Once anchored onto the inner walls of the tube, the endothelial cells began sprouting new, capillary-like vessels in the gel. And when the researchers moved the embedded magnet back and forth in different directions and by varying degrees, they found that the mechanical forces created by the moving magnet could stretch the vessels and increase the number of new capillaries that grew, as well as their length.
“We also showed that blood vessel growth, or angiogenesis, could be directionally patterned using the mechanical forces created by the magnet and that these directions could change dynamically over time,” explains Raman. “This allows us to ‘steer’ blood vessel growth in all three spatial directions (x, y, z) and make complex geometries (like L-shaped branches) that would not be possible to fabricate using conventional methods.”
The researchers had previously demonstrated that biological cells are highly responsive to mechanical forces in the body, but they did not know how different types of forces – for example, stretching in different directions and at different degrees and frequencies – impacted the 3D structure of blood vessels. The main obstacle lay in developing a coupled magnet system to precisely stretch blood vessels in different directions. To achieve this, they designed a method for mechanically stimulating tissues, dubbed “magnetic matrix actuation”.
In their new work, which is detailed in PNAS, they went a step further and developed a method to accurately yet non-invasively stretch 3D blood vessel tissues they had built in the laboratory.
To better understand the effect of mechanical forces on angiogenesis, the MIT team decided to look into the role of a gene known as PIEZO1, which is just one of the many mechanically sensitive genes in the body. They built on the work of molecular biologist Ardem Patapoutian, who received the 2021 Nobel Prize in Physiology or Medicine for discovering that ion channels in cells open and close in response to mechanical pressure. One such ion channel is PIEZO1, which is regulated by the PIEZO1 gene.
By suppressing this PIEZO1 gene in the endothelial cells they studied, the researchers indeed observed that significantly fewer new blood vessels grew in the gel. This, they say, provides evidence that the applied mechanical forces in their experiment may have been opening the PIEZO1 ion channel in the endothelial cells, so triggering the new blood vessel growth.
“My group has always been interested in engineering artificial tissues that can be implanted in the body to repair damage caused by disease or traumatic injury, but such artificial tissues require integrated networks of blood vessels in order to function,” says Raman. “We hope that our method for precisely fabricating complex networks of blood vessels within engineered tissues will enable the development of such implants,” she tells Physics World.
The post Artificial blood vessels grow with the help of mechanical forces appeared first on Physics World.
A quiet shift in silicon manufacturing could be taking shape inside a new study on porous reaction-bonded silicon nitride, a ceramic material valued for its strength, thermal stability and resistance to chemical attack. Researchers T.G. Aguirre, E. Cakmak, M.D. Richardson and colleagues are investigating how the size of additively manufactured silicon components affects their conversion into silicon nitride through a pressureless nitriding process. Published in npj Advanced Manufacturing, the work connects binder jet 3D printing with a manufacturing route that could make complex ceramic structures easier to produce.
The central idea is deceptively simple: print a component from silicon powder, then expose it to nitrogen so that the silicon reacts and forms silicon nitride. In practice, however, the transformation is governed by a network of interacting physical and chemical processes. Nitrogen must penetrate the part, reach reactive silicon surfaces and diffuse through newly formed ceramic layers. Heat must also move through the structure, while gases generated or trapped during processing must escape. As component dimensions change, these processes can behave very differently.
Binder jet additive manufacturing offers a distinctive route for creating such parts. Instead of melting powder with a laser or electron beam, the process selectively deposits a liquid binder to join powder particles layer by layer. The resulting “green” component is then typically dried and thermally treated to remove the binder, leaving a fragile, porous body. For silicon-based structures, that interconnected porosity can become a processing advantage, allowing nitrogen to travel through the material during the subsequent reaction.
The researchers’ focus on size effects addresses a major challenge in scaling ceramic additive manufacturing from laboratory specimens to useful components. A thin printed sample may nitridize relatively quickly because nitrogen has only a short distance to travel. A thicker or larger part presents a far more demanding environment. Its interior can receive nitrogen more slowly, and the reaction front may progress unevenly from the outer surface inward. Differences in heating rate, temperature distribution and gas transport can produce variations in conversion, density and final microstructure.
The term “pressureless nitriding” is crucial to the study’s technological appeal. Many advanced ceramic manufacturing methods depend on external pressure, specialized furnaces or high-energy consolidation steps to achieve the desired structure. A pressureless route instead relies on controlled heating and the chemical affinity between silicon and nitrogen. If the reaction can be managed uniformly, manufacturers could potentially create intricate silicon nitride components without applying mechanical pressure during conversion, simplifying equipment requirements and expanding the range of printable geometries.
Silicon nitride is an especially attractive target because it combines several properties that are difficult to obtain in a single engineering material. It can withstand high temperatures, resist wear and corrosion, and maintain useful mechanical performance under demanding conditions. Those characteristics have made silicon nitride relevant to applications ranging from bearings and cutting tools to heat-resistant components and advanced energy systems. A porous version offers additional possibilities, including lightweight structures, filtration, thermal management and engineered surfaces where controlled pathways through the material are valuable.
The study’s attention to porosity is equally important. In reaction-bonded ceramics, pores are not merely defects; they can serve as channels for reactant transport. At the same time, excessive or poorly distributed porosity can weaken the final component and interfere with complete conversion. The scientific challenge is therefore to balance openness and strength. The printed silicon body must remain permeable enough for nitrogen to reach its interior, while the reaction must generate a coherent silicon nitride framework rather than leaving unreacted silicon or creating damaging gradients.
By examining components of different sizes, the researchers are addressing a question with direct implications for industrial design: can processing rules developed for small printed samples be applied to larger parts? The answer depends on how reaction kinetics, diffusion and heat transfer scale with geometry. A process that appears reliable in a small coupon may produce a different result in a thick wall, enclosed channel or complex lattice. Understanding those differences can help engineers determine allowable dimensions, optimize furnace schedules and design structures around the chemistry of nitridation rather than treating manufacturing as a purely geometric exercise.
The broader significance of the work lies in the convergence of three fields: powder-based additive manufacturing, reaction-bonded ceramics and transport-driven materials processing. Instead of printing a finished ceramic directly, the approach uses additive manufacturing to create a carefully engineered precursor and then transforms it chemically. That strategy could unlock shapes that are difficult to machine from dense silicon nitride, while reducing the need for conventional molds and tooling. As manufacturers seek lighter, more complex and more resource-efficient components, controlling size-dependent reactions may become as important as improving printer resolution.
The research arrives at a moment when additive manufacturing is moving beyond demonstrations of intricate shapes toward repeatable production of functional materials. Its emphasis on pressureless nitriding of binder jet additively manufactured silicon highlights a practical bottleneck often hidden behind spectacular 3D-printing images: the printed object is only the beginning. The final performance depends on what happens during post-processing, when gases, heat and chemical reactions determine the internal structure. By clarifying how component size influences that transformation, Aguirre, Cakmak, Richardson and their collaborators are helping map a route from powder and binder to porous silicon nitride parts designed for the high-temperature technologies of the future.
Subject of Research: Porous reaction-bonded silicon nitride produced through pressureless nitriding of binder jet additively manufactured silicon, with a focus on size effects.
Article Title: Porous reaction-bonded silicon nitride: Size effects for pressureless nitriding of binder jet additively manufactured silicon
Article References: Aguirre, T.G., Cakmak, E., Richardson, M.D. et al. “Porous reaction-bonded silicon nitride: Size effects for pressureless nitriding of binder jet additively manufactured silicon.” npj Advanced Manufacturing (2026). https://doi.org/10.1038/s44334-026-00110-y
Image Credits: AI Generated
DOI: 10.1038/s44334-026-00110-y
Keywords: Silicon nitride, reaction-bonded ceramics, pressureless nitriding, binder jet additive manufacturing, silicon, porous materials, size effects.
Bacterial cellulose—nature’s own polymer scaffold—is gaining attention as a renewable feedstock for supercapacitor electrodes. With modern devices demanding fast charge, high power bursts, and long cycle life, researchers are searching for electrode materials that combine performance with sustainability.
A new systematic literature review led by Prof. Dahlang Tahir at Hasanuddin University, Indonesia, maps how bacterial cellulose-derived carbon (BCC) is turned into energy-storage electrodes—and why some fabrication paths outperform others. The study synthesizes evidence from the scientific record to clarify which processing choices control electrochemical behavior.
The review focuses on BCC as a precursor to porous carbon. Bacterial cellulose forms a naturally pure, interconnected network of nanoscale fibers, and heat treatment can convert that architecture into carbon structures with tunable porosity—critical for charge storage. The authors emphasize that electrical performance is not just a matter of “making carbon,” but of preserving and engineering the fiber network before carbonization.
Across 49 Scopus-indexed journal articles, the team compares major strategies including direct carbonization, chemical activation to enlarge pore systems, heteroatom doping to modify surface chemistry, and composite fabrication with materials that can add rapid redox (pseudocapacitive) contributions.
A recurring message is the importance of pre-carbonization drying. Freeze-drying appears as the most commonly used approach because it limits collapse of the wet nanofiber structure during water removal. Since pore architecture governs ion access and charge transport, maintaining nanoscale structure can translate into higher effective capacitance.
The review also distinguishes test formats. Three-electrode measurements are frequently reported, but two-electrode devices better represent real supercapacitor operation, where electrode–electrode interactions shape performance.
When processing is optimized, the results point toward a pathway for BCC-based electrodes to rival or surpass commercial activated carbon under comparable conditions. Activation and heteroatom doping generally increase accessible surface area and create additional active sites, while composites often achieve the strongest capacitance by combining electrical double-layer effects with fast surface reactions.
Yet the authors warn that progress is constrained by inconsistent experimental reporting, uneven protocols, and limited mechanistic understanding. To move beyond laboratory demonstrations, they call for predictive design, data-driven structure–performance models, scalable carbonization methods, and robust flexible devices resistant to deformation and humidity.
Subject of Research: Supercapacitor electrodes using bacterial cellulose-derived carbon
Article Title: Bacterial cellulose-derived carbon electrodes for supercapacitors: Fabrication strategies, electrochemical performance, and mechanical properties — A review
News Publication Date: 9 June 2026
Web References: https://doi.org/10.1016/j.est.2026.123044
References: 10.1016/j.est.2026.123044
Image Credits: Lightenoughtotravel from Wikimedia Commons
bacterial cellulose; supercapacitors; porous carbon; freeze-drying; chemical activation; heteroatom doping; electrode materials; two-electrode testing; pseudocapacitance; sustainable energy storage
In a groundbreaking development poised to redefine waste management and sustainable energy production, researchers have unveiled a revolutionary method for photoreforming solid waste on an unprecedented 1-square-meter scale. This innovative advance, detailed in the latest issue of Nature Chemical Engineering, leverages single-source precursor-derived co-catalyst films to convert ubiquitous solid waste into valuable chemical fuels, heralding a new era in environmental remediation coupled with renewable energy generation.
At the heart of this innovation lies the principle of photoreforming, a process by which sunlight catalyzes the chemical transformation of organic materials into hydrogen and other energy-rich molecules. Historically limited to small-scale demonstrations and powdered catalysts, this method struggled with scalability and practical application outside controlled laboratory settings. The reported technique shatters these limitations by fabricating robust co-catalyst films derived from a unified precursor source, enabling efficient photoconversion across large surface areas with enhanced stability and performance.
The researchers crafted these functional films through an ingenious synthesis route, where a single molecular precursor simultaneously yields both the active catalytic sites and the supporting matrix. This contrasts with conventional multi-step fabrication approaches that often result in inconsistent catalyst dispersion and energy losses. By integrating the catalyst components at the molecular level, the team ensured homogeneity, maximized photon absorption, and optimized charge separation dynamics, all critical parameters for sustained photocatalytic activity.
Transforming real-world solid waste – encompassing plastics, biomass residues, and mixed refuse – into clean fuels presents a formidable challenge due to their complex chemical compositions and structural heterogeneity. The co-catalyst films demonstrated remarkable versatility and adaptability, efficiently processing these diverse substrates under simulated sunlight without requiring extensive pre-treatment. This robustness signals a significant leap toward practical deployment in municipal waste processing facilities and industrial settings.
The experimental setup encompassed a square meter of coated substrate exposed to controlled illumination, mirroring natural sunlight intensity conditions. Over extended operation, the system consistently yielded high rates of hydrogen and other value-added chemicals, outperforming benchmark photocatalysts by a considerable margin. Importantly, the films manifested remarkable photostability and mechanical adhesion, demonstrating resilience against degradation mechanisms like photo-corrosion and mechanical abrasion that typically afflict photocatalytic layers.
At the nanoscale, characterization techniques revealed uniform distribution of nanosized catalytic domains embedded within a conductive, photoactive matrix. This architecture ensures rapid electron-hole separation and transport, minimizing recombination losses which commonly plague photocatalytic systems and limit hydrogen evolution rates. Spectroscopic analyses corroborated enhanced visible-light absorption, attributed to tailored bandgap engineering achieved during precursor design, broadening the usable solar spectrum beyond ultraviolet wavelengths.
The process design also embraced mass transport optimization, incorporating porous film structures that facilitated effective diffusion of reactants and removal of gaseous products. This morphologic control prevented stagnation zones and concentration gradients, enhancing catalytic turnover and ensuring stable long-term performance. Additionally, the modular film fabrication approach promises scalability and integration into various reactor geometries without compromising catalytic efficiency.
Beyond hydrogen generation, the system also showcased the capacity to produce liquid fuels and chemical feedstocks, capitalizing on selective reaction pathways induced by co-catalyst composition tuning. This selectivity allows tailored conversion routes matching industrial chemical demands, moving beyond mere waste disposal toward circular chemical economies. The dual benefit of environmental waste mitigation coupled with clean energy and chemical synthesis embodies transformative potential for sustainable industrial practices.
Critically, the team emphasized the environmental and economic implications of adopting such technology at scale. By converting problematic solid waste streams into valuable resources using sunlight – a free and abundant energy source – this approach diminishes reliance on fossil fuels and reduces landfill burden. Cost analyses suggested that, once scaled, the technique could rival established catalytic processes in operational expenditure, thus offering an attractive proposition for policymakers and industry leaders aiming to meet stringent environmental targets.
The interdisciplinary collaboration instrumental in achieving this advance integrated expertise across materials chemistry, photophysics, environmental engineering, and nanofabrication. Such synthesis of disciplines underscored the inherent complexity of developing scalable photocatalytic platforms capable of handling real-world waste complexities while maintaining high efficiency and durability.
Looking ahead, the researchers are exploring further enhancements including tandem catalyst layers, optimized co-catalyst configurations, and hybrid photochemical-electrochemical systems to elevate the energy conversion efficiency and broaden substrate compatibility. In parallel, pilot-scale demonstrations are underway to validate system performance in outdoor environments subject to variable weather conditions, pivotal for transitioning laboratory innovation into field applications.
This pioneering work sets a new benchmark in photoreforming science, illustrating how precise molecular engineering and thoughtful system design can transform a pressing global challenge—solid waste accumulation—into a renewable energy opportunity. Its implications resonate strongly with global sustainability aspirations, promising an economically feasible and environmentally benign pathway to simultaneously address climate change mitigation, waste reduction, and clean energy production.
As society grapples with mounting waste generation paired with escalating energy demands, innovations such as these underscore the invaluable role of scientific ingenuity in crafting solutions that are as elegant as they are practical. By harnessing the synergy of sunlight and advanced material chemistry, the future of waste management is illuminated—not as a burden, but as a wellspring of renewable chemical energy.
In summary, this major scientific milestone demonstrates that photoreforming solid waste at a 1 m² scale using single-source precursor-derived co-catalyst films is no longer a theoretical possibility but a tangible technological reality. It unequivocally paves the way for deploying solar-driven catalytic systems in addressing environmental and energy crises through smart design and scalable engineering.
Subject of Research:
Photoreforming of solid waste using single-source precursor-derived co-catalyst films.
Article Title:
Photoreforming of solid waste on 1 m² scale using single-source precursor-derived co-catalyst films.
Article References:
Bin Mohamad Annuar, A., Liu, Y., Bhattacharjee, S. et al. Photoreforming of solid waste on 1 m² scale using single-source precursor-derived co-catalyst films. Nat Chem Eng 3, 351–362 (2026). https://doi.org/10.1038/s44286-026-00406-y
Image Credits:
AI Generated
DOI:
10.1038/s44286-026-00406-y
Keywords:
Photoreforming, solid waste conversion, co-catalyst films, solar energy, hydrogen production, photocatalysis, renewable energy, waste-to-fuel, sustainable chemistry, scalable catalysis
In a groundbreaking advancement for optoelectronic technology, researchers have unveiled a novel approach harnessing the unique properties of Si₃N₄/n-Si hybrid devices to achieve interface-controlled broadband photodetection. This development promises to revolutionize the efficiency and spectral range of photodetectors, devices integral to a wide array of applications from telecommunications to environmental monitoring. The study, recently published in Scientific Reports, highlights how meticulous control over material interfaces can dramatically enhance device performance, marking a significant leap forward in photodetector design and fabrication.
Photodetectors serve as the eyes of modern electronic systems, converting light into electrical signals that enable everything from digital imaging to fiber optic communication. Traditional photodetectors, however, have long been limited by narrow operational bandwidths and sensitivity constraints, curbing their effectiveness in emerging high-performance applications. By integrating silicon nitride (Si₃N₄) with n-type silicon (n-Si), the researchers have engineered a hybrid platform that deftly overcomes these limitations, exploiting interface phenomena to extend detection capabilities across a broad spectrum of electromagnetic radiation.
At the heart of this innovation lies the strategic manipulation of the Si₃N₄/n-Si interface. Silicon nitride, known for its excellent dielectric properties and chemical stability, acts as both a passivation layer and an optical modulator when interfaced with silicon. This interplay at the atomic and electronic scale shapes charge carrier dynamics, reduces surface recombination losses, and enhances photon absorption efficiency. Such interface engineering ensures that the hybrid device is not only highly sensitive but also capable of operating seamlessly over a wide range of wavelengths, from ultraviolet through visible to near-infrared.
The research team deployed advanced fabrication techniques to precisely control the deposition and interface formation of Si₃N₄ on the n-Si substrate. Utilizing plasma-enhanced chemical vapor deposition (PECVD), they achieved a uniform and defect-minimized nitride layer that adheres perfectly to the silicon surface. This meticulous fabrication step is essential as interface traps, commonly induced by imperfections, can severely degrade photodetector responsiveness and noise levels. By minimizing such imperfections, the hybrid device attains an unprecedented signal-to-noise ratio crucial for sensitive detection tasks.
Optical characterization of the Si₃N₄/n-Si hybrids revealed remarkable broadband responsivity, a parameter quantifying the device’s ability to convert incoming photons across various wavelengths into electric current. The devices demonstrated enhanced photoresponse not only in the visible spectrum but also extended into ultraviolet and infrared regions, surpassing conventional silicon-based photodetectors limited by the bandgap constraints of pure silicon. This broadband sensitivity opens the door to new applications where multispectral light detection is necessary without the need for separate sensors.
One of the pivotal mechanisms for this extended response is the formation of interfacial states that facilitate charge transfer and broaden the spectral detection range. These states effectively lower the energy barriers that typically restrict silicon’s photoresponse, enabling efficient utilization of photons with energies both above and below the traditional silicon bandgap. This effect is modulated by the thickness and stoichiometric composition of the Si₃N₄ layer, parameters finely tuned during device fabrication to optimize performance.
Beyond spectral coverage, the temporal response of these hybrid photodetectors is equally impressive. The devices exhibited fast switching times and low dark currents, essential characteristics for high-speed communications and low-light detection scenarios. Reduced dark current, a measure of unwanted noise in the absence of illumination, directly correlates with enhanced sensitivity, thereby allowing the detection of weak optical signals with unprecedented clarity.
Integration compatibility is another striking advantage of the Si₃N₄/n-Si system. Both materials are well-established in mainstream semiconductor manufacturing, meaning that this innovation can be seamlessly incorporated into existing silicon-based electronic platforms. This compatibility facilitates scaling production while maintaining cost efficiency, a critical factor for commercial adoption in industries such as consumer electronics, healthcare diagnostics, and environmental sensing.
The research also delves into the underlying physics governing the device operation. Through combined experimental and theoretical analyses, the study elucidates charge carrier transport across the interface, the role of interface dipoles, and modulation of the built-in electric field that directs photogenerated carriers. Such detailed understanding offers a roadmap for further improvements, potentially inspiring future hybrid systems with tailored optoelectronic properties suitable for specific industrial applications.
In terms of real-world application, these hybrid photodetectors could significantly enhance the performance of cameras, optical coherence tomography devices, and remote sensing instruments. The broadband detection capability reduces the reliance on multiple sensors, simplifying device architectures and improving reliability. Additionally, their fast response times and stability under various environmental conditions are promising for deployment in harsh or variable environments, including space exploration and autonomous vehicle navigation.
This research marks a notable shift in photodetector technology by emphasizing interface engineering to transcend inherent material limitations. By capitalizing on the complementary properties of Si₃N₄ and n-Si junctions, the study injects fresh momentum into the pursuit of universal photodetectors that excel in speed, sensitivity, and spectral range. The findings underscore the vast potential lying in hybrid material systems, motivating continued exploration into interface-controlled photonic devices.
Looking forward, the researchers suggest exploring further modifications to the Si₃N₄ layer such as doping or introducing nanoscale structuring to tailor the interface behavior. Such advancements may unlock new functionalities like polarization sensitivity or even tunable wavelength selectivity, pushing hybrid photodetectors beyond current performance frontiers. These directions align with the broader scientific quest to develop smarter, more adaptable optoelectronic components for the next generation of information and sensing technologies.
In conclusion, the Si₃N₄/n-Si hybrid photodetector described in this study represents a pivotal development that combines material science innovation with practical engineering to address longstanding challenges in photodetection. Its broadband capability, operational stability, and integration potential poise it as a top candidate for a wide spectrum of applications demanding fast, efficient, and reliable light detection. As industries continue to demand more from photonic devices, such interface-controlled systems stand out as a transformative solution poised to redefine the future of photodetection technology.
Subject of Research: Interface-controlled broadband photodetection in Si₃N₄/n-Si hybrid devices
Article Title: Interface-controlled broadband photodetection in Si₃N₄/n-Si hybrid devices
Article References:
Manfo, T.A., Yıldız, D.E., Bağcı, C. et al. Interface-controlled broadband photodetection in Si₃N₄/n-Si hybrid devices. Sci Rep (2026). https://doi.org/10.1038/s41598-026-57951-y
Image Credits: AI Generated
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