Research

The Extent of Drought Areas Shapes Public Response

[POSTECH, the National Disaster Management Research Institute, and the Korea Research Institute for Human Settlements analyze society’s view of disasters using AI] How do people’s attention and actions change when a drought affects the whole country compared to when it is concentrated in one region? A research team led by Professor Jong-Hoon Kam from the Department of Environmental Engineering at POSTECH analyzed news reports, social media posts, and internet search data using artificial intelligence (AI) during the 2022–2023 drought period. The team found that public views of disasters change depending on the size of the problem and its distance from people. The study was recently published online in the international journal Humanities and Social Sciences Communications. A drought does not happen all at once. It usually starts as a meteorological drought, when rainfall decreases. It then develops into an agricultural drought, when soil dries out, and later to a hydrological drought, when water levels in rivers and reservoirs fall. If these physical droughts last for a long time, they can turn into a socioeconomic drought that affects industry and daily life. As these environmental changes happen step by step, people’s awareness, emotions, and ways of searching for information also change. This idea was the starting point of the study. The research team focused on how a nationwide drought in 2022 became concentrated in the Gwangju and Jeonnam regions in 2023. They collected news articles, social media posts, and internet search records created during the drought period and analyzed them using AI based on natural language processing. This allowed them to measure how public interest, emotions, and behavior changed as the scale of the disaster changed. The results showed that in June 2022, when the nationwide drought was at its worst, internet searches, news coverage, and social media posts all reached their highest levels. In contrast, in March 2023, when the drought was mainly limited to the southwestern region of Korea, local news coverage and search activity increased, but social media posts declined relatively. When the drought was a national issue, people spoke more. When it became a regional issue, people mostly just looked for information. An analysis of emotions in news headlines also showed an interesting pattern. Throughout the study period, the emotions of “expectation,” “anxiety,” and “disappointment” appeared repeatedly. People felt hopeful when rain was forecast but felt disappointed when it did not come. This cycle continued throughout the drought period. This shows that media coverage and public emotions are closely connected during disasters. The study suggests that disaster response should go beyond technical solutions to water shortages and consider public awareness and communication. By using big data and AI to understand social reactions in advance, drought warnings, policy messages, and response strategies can be designed more effectively. Professor Kam said, “This study provides a new perspective of drought mitigation because it uses AI to analyze unstructured data like news articles and personal posts to understand social emotions and behavior during disasters.” He added, “The results hints how to improve future drought response and risk communication strategies.” The study was supported by the Disaster and Safety Joint Research and Development Program of the Ministry of the Interior and Safety of Korea. ▶️ DOI: https://doi.org/10.1057/s41599-025-06398-z

AI Learns to Perform Analog Layout Design

[POSTECH researchers demonstrate a foundation model for automating analog circuit layout design] Researchers at POSTECH have developed an artificial intelligence approach that addresses a key bottleneck in analog semiconductor layout design, a process that has traditionally depended heavily on engineers’ experience. The work was recently published in IEEE Transactions on Circuits and Systems I (TCAS-I), an international journal in the circuits and systems field. Semiconductors are used in a wide range of technologies, including smartphones, vehicles, and AI servers. However, analog layout design remains difficult to automate because designers must manually arrange structures that dertermine performance and reliability while meeting a large number of design rules. Automation has been especially challenging in analog design because layouts are too complex and design strategies differ significantly by circuit. In addition, training data is scarce, since layout data is typically treated as proprietary and is rarely shared outside companies. The POSTECH team, led by Professor Byungsub Kim in the Department of Electrical Engineering, focused on the “foundation model” approach. A foundation model is first pre-trained on large-scale data and can then be adapted to different downstream tasks with relatively little additional training. The researchers applied this concept to analog layout design. The key method is self-supervised learning, in which the model learns without human-provided labels. The team divided analog layouts1) into small patches, masked part of each layout, and trained the model to predict the missing layout elements. Using this procedure, the researchers generated about 320,000 training samples from six real layout datasets. After pre-training, the model learned repeated structures and patterns commonly found in analog layouts. With limited additional data, it was then adapted to five layout-related tasks: contact generation, via generation, dummy pattern insertion, N-well generation, and metal routing. In experiments, 96.6% of the generated layouts reportedly passed both design-rule checking and layout versus schematic verification. The team also reported that comparable performance was achieved using one-eighth of the data required by conventional approaches. The study suggests that a single foundation model can be leveraged for multiple analog layout tasks, reducing the need to build a separate model for each task. The researchers said the approach could reduce design workload and shorten development time, improving productivity in semiconductor design. “This work meaningfully expands the practical feasibility of automating analog semiconductor layout design, which has been constrained by data scarcity,” Professor Kim said. First author Sungyu Jeong said, “The main contribution of this work is the methodology that enables large-scale learning.” He added, “Our goal is to collect more data and continue developing the foundation model to a practically usable level”. The study was conducted by Professor Kim, Ph.D. candidate Sungyu Jeong, Wonjun Choi, and Junwoong Choi, and master’s graduate Anik Biswas (currently at Samsung Electronics). The project received support from Korea’s Ministry of Science and ICT, the Institute for Information & Communications Technology Planning & Evaluation (IITP), the National Research Foundation of Korea (NRF), the Korea Institute for Advancement of Technology (KIAT), and the BK21 Education and Research Program. ▶️ DOI: https://doi.org/10.1109/TCSI.2025.3615646 1. Analog layout: The physical geometry (patterns) used to implement an analog circuit on a semiconductor chip.

Upcycling genes: New platform breathes life into underperforming genetic parts

[Professor Jongmin Kim’s research team at POSTECH develops ‘SUPER’ platform, significantly enhancing the performance and stability of gene regulatory devices] A research team led by Professor Jongmin Kim of the Department of Life Sciences at POSTECH, along with graduate students Taeyang Heo, Dongwon Park, and Woosub Shin, has developed the 'SUPER (Synthetic Upcycling Platform for Engineering Regulators)' platform, which dramatically enhances the performance and stability of gene regulatory devices. This research was recently published in Advanced Science, an international peer-reviewed journal. Synthetic biology utilizes genetic components as programmable building blocks to endow cells with new functions. As such, synthetic biology is poised to revolutionize bioengineering and biotechnology in addressing future challenges. The adoption of synthetic genetic switches that control genes 'ON' and 'OFF' is accelerating due to the advantages of compact and modular architecture and strong performance for developing next-generation biosensors, cell-based therapeutics, and biofactories. Still, a critical challenge remains for these synthetic genetic switches where the ‘OFF’ state is not really OFF at the molecular level. Much like a dripping faucet even when completely turned off, genetic switches continue to express at low levels even in the 'OFF' state—a phenomenon known as 'leakage.' Although it may look harmless on the surface, this small leakage can accumulate over time, place a long-term metabolic burden on cells, and compromise circuit stability, ultimately requiring a complete overhaul of the system. To address this challenge, the team developed ‘SUPER’, a platform technology that utilizes synthetic small RNAs1) as add-on controllers for genetic switches. This principle is analogous to inserting an extra gasket into a leaky faucet to restore its function. The key advantage of ‘SUPER’ is to bypass engineering target devices altogether, yet still achieve dramatically enhanced functionality by simple add-on controllers. When enhanced with the SUPER platform, natural and synthetic genetic switches showed performance improvements of up to 1,011% with a tunable dynamic range2)—the ability to distinguish between ON and OFF signals—up to 22,000-fold. These performance metrics could be easily adjusted by small RNAs in the SUPER platform, thereby enabling flexible, context-dependent regulation of synthetic genetic switches. Building on this foundational technology, the team also demonstrated dramatic improvement in cellular 'kill switches'—safety mechanisms designed to prevent unintended spread of engineered organisms in gene therapy and bioprocessing. Previously, kill switch circuits often suffered from residual leaky expression that could lead to loss of functional circuits and the emergence of resistance in cells. Kill switches enhanced with SUPER remained stable for over 30 days in engineered cells, with the ability to integrate environmental signals such as chemical inputs and temperature. Professor Jongmin Kim stated, "SUPER is an upcycling technology that enhances both the performance and stability of existing genetic components without changing those components." He added, "With SUPER, we anticipate that a wide array of genetic parts that were previously overlooked could be put to use for broad application areas including live biotherapeutics and biomanufacturing“. This research was supported by the Korea Health Industry Development Institute, the Gyeongsangbuk-do and Pohang City Synthetic Biology Support Program, the Ministry of Education BK21 FOUR Program, Gyeongbuk Technopark, the Ministry of Agriculture, Food and Rural Affairs' Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry, the Korea Basic Science Institute, and the National Research Foundation of Korea. ▶️ DOI: https://doi.org/10.1002/advs.202514653 1. small RNA: Short RNA molecules that do not encode proteins but regulate the expression of other genes. In this study, they were utilized as an 'auxiliary brake' for genetic switches. 2. Dynamic Range: A metric indicating the difference in expression levels between the 'ON' and 'OFF' states of a genetic switch. A wider dynamic range enables more precise signal discrimination.

Gut microbe–derived butyrate activates immune cells to enhance vaccine efficacy

[POSTECH and ImmunoBiome researchers uncover a novel microbiota-Tfh cell axis to enhance antibody production and mucosal vaccine efficiency] A research team from POSTECH and ImmunoBiome in Korea, led by Professor Sin-Hyeog Im, has uncovered a new mechanism showing how butyrate—a short-chain fatty acid produced by gut commensal bacteria—enhances T follicular helper (Tfh1)) cell activity to promote antibody production and strengthen mucosal vaccine efficacy. This study identifies a new microbiota–immune–antibody production axis linking microbial metabolism to mucosal immune responses, providing a strategy to maximize the protective effects of mucosal vaccines. The findings were recently published in the international journal Microbiome. Mucosal vaccines and the challenge they face Mucosal vaccines are gaining attention as a next-generation vaccination approach because they can be administered non-invasively and elicit immune responses directly at mucosal surfaces, such as the gut or respiratory tract—common sites of infection. However, their development has been hampered by several challenges: antigens must survive harsh gastric conditions, penetrate mucus barriers, and overcome the intestine’s tolerogenic environment. Consequently, these vaccines often require high antigen doses, potent adjuvants, or complex delivery systems, raising concerns about safety and cost. The present study provides a novel solution by demonstrating that butyrate, a naturally occurring microbial metabolite, acts as an innate adjuvant2) that enhances mucosal vaccine responses safely and effectively. Key findings: a microbiota-Tfh-lgA axis Although the gut microbiota is known to play a critical role in maintaining immune homeostasis, its influence on mucosal antibody responses has remained unclear. The POSTECH-ImmunoBiome team discovered that Peyer’s patch–derived Tfh cells in the small intestine have a much stronger ability to induce IgA antibody production than splenic Tfh cells. When antibiotic treatment (neomycin) depleted specific bacterial groups, both fecal IgA levels and Tfh cell frequencies declined significantly; these effects were restored following fecal microbiota transplantation. Further analysis identified Lachnospiraceae and Ruminococcaceae, major butyrate-producing taxa, as key microbial drivers sustaining the Tfh–IgA axis. Mechanistic studies revealed that butyrate promotes Tfh differentiation and IgA⁺ germinal center B cell formation, thereby boosting mucosal IgA production. Administration of tributyrin, a butyrate prodrug, significantly enhanced IgA responses and protection against Salmonella Typhimurium infection, reducing both infection rates and tissue damage. This effect was abolished in GPR43-deficient cells, confirming that the butyrate–GPR43 signaling pathway mediates Tfh activation and IgA induction. Implications This study demonstrates that butyrate, a metabolite produced by gut microbes, establishes a new microbiota–Tfh–IgA axis, linking commensal metabolism to antibody-mediated mucosal defense. These results highlight the crucial role of gut environment regulation in controlling infections and enhancing vaccine responses. Professor Sin-Hyeog Im (POSTECH and CEO of ImmunoBiome, Inc.) stated, “Our findings reveal that gut microbes are not just passive residents but active modulators of the immune system. Microbial metabolites can directly enhance the function of immune cells essential for antibody production and vaccine efficacy. This discovery opens new avenues for developing microbiota-based adjuvants and next-generation mucosal vaccines.” About ImmunoBiome ImmunoBiome is a leading biotech company in Korea, focusing on developing Live Biotherapeutic Products (LBPs) for difficult-to-treat diseases, including cancer, autoimmune disorders, and neurodevelopmental conditions. Using its proprietary Avatiome™ platform, ImmunoBiome selectively identifies and develops pharmacologically active bacterial strains, studies their immune mechanisms, and creates therapeutic pipelines based on microbial-derived molecules. The company maintains an extensive database of human commensal bacteria collected from mucosal surfaces and works closely with POSTECH and international research partners. By combining AI-driven analytics, immune profiling, and microbiome science, ImmunoBiome is advancing precision microbiome-based therapies and consumer products designed to influence host health through the gut–immune axis. Funding This research was conducted in close collaboration between POSTECH and ImmunoBiome, Inc. The study was supported by ImmunoBiome, the National Research Foundation of Korea (NRF) funded by the Ministry of Education and the Ministry of Science and ICT, and the Institute for Basic Science (IBS). ▶️ DOI: https://doi.org/10.1186/s40168-025-02284-7 1. Tfh (T follicular helper cell): A subset of helper T cells that support B cell activation and antibody production, playing a key role in maintaining antibody responses and regulating immune reactions related to vaccines and autoimmunity. 2. Adjuvant: A component added to vaccines to enhance immune responses and promote antibody production, thereby improving vaccine efficacy.

“A New Security Technology That Locks Information with Light Color and Distance” — Unhackable Metasurface Holograms

[POSTECH team develops a next-generation secure hologram platform where light wavelength and interlayer spacing act as encryption keys] A research team led by Professor Junsuk Rho at POSTECH has developed a secure hologram platform that operates solely based on the wavelength of light and the spacing between metasurface layers. The technology makes hacking and counterfeiting virtually impossible, and is expected to be widely adopted for security cards, anti-counterfeiting, and military communications. With a growing number of hacking incidents and data breaches, the limitations of digital security are becoming increasingly evident. No matter how sophisticated an encryption scheme is, as long as it exists as code, it is difficult to completely eliminate the risk of intrusion. Motivated by this challenge, the team proposed a new approach that uses the physical conditions of light itself as a security key. At the core of this innovation is the “metasurface,” an ultrathin optical device that arranges microscopic structures to control light. By illuminating a metasurface, a holographic image can be reconstructed in free space. However, conventional holograms have typically been limited in that a single device could store only one piece of information. To overcome this limitation, the researchers designed a “modular diffractive deep neural network,” applying concepts from artificial neural networks to optical structures. In this architecture, light propagation and interference autonomously perform computations, enabling information processing using light alone—without electrical power or electronic chips. Each metasurface functions as a layer of the neural network, and the team trained the system such that entirely different outputs emerge when layers are used individually versus when they are combined. For example, illuminating the metasurface with a specific wavelength reconstructs an ID hologram, while a different wavelength produces a completely different image. Another layer might reconstruct QR-code information. In other words, each layer independently stores distinct information. The technology’s true potential appears when two or more metasurfaces are combined. When two layers are positioned at a precise separation and illuminated with a specific wavelength, an encrypted hologram—corresponding to a password—appears. If the wavelength or the interlayer spacing deviates even slightly, the information remains hidden. In this way, the color of light and the distance between layers function as a “physical password.” Notably, in theory, as the number of wavelengths (m) and the number of metasurface layers (N) increase, the number of information channels grows exponentially as m(2ⁿ−1). This suggests that the security levels and combinations of information achievable within a single device can be expanded virtually without limit. The team expects the technology to be applicable to anti-counterfeiting labels for IDs and passports, secure military and diplomatic documents, and next-generation optical communications. “By using the physical properties of light itself as a security key, this study could fundamentally reshape the paradigm of conventional digital security,” said Professor Junsuk Rho. “As digital technologies become more advanced, our results highlight that physical security can ultimately provide the strongest solution.” This research was carried out by Professor Junsuk Rho’s team at POSTECH (Department of Mechanical Engineering; Department of Chemical Engineering; Department of Electrical Engineering; and the Graduate School of Convergence Science and Technology). The work was published in Advanced Functional Materials, an international journal in materials science and nanotechnology, and was supported by the POSCO-POSTECH-RIST Convergence Research Institute and the National Research Foundation of Korea. ▶️ DOI: https://doi.org/10.1002/adfm.202523309

A Slight Twist, a Big Change: Atomic Registry Reshapes Electrons

[POSTECH, the University of Wisconsin–Madison, and the University of Tokyo control oxide electronic structures via local atomic arrangements at moiré interfaces] It has been revealed that simply twisting and stacking two layers of oxide crystals can allow the atomic arrangement itself to control the behavior of electrons. Much like the new patterns that emerge when two meshes are overlapped and rotated, a twisted oxide interface forms specific atomic configurations that act as an “invisible fence,” either trapping or repelling electrons. A research team led by Prof. Si-Young Choi in the Department of Materials Science and Engineering and the Department of Semiconductor Engineering at POSTECH, in collaboration with Prof. Chang-Beom Eom and postdoctoral researcher Kyoungjun Lee at the University of Wisconsin–Madison, and Prof. Ryo Ishikawa at the University of Tokyo, has elucidated the mechanism underlying this phenomenon in twisted oxide interfaces formed at specific rotation angles. This work was published as a cover article in the international journal ACS Nano. The key concept of the study is the moiré pattern1). When two lattices are stacked and one layer is slightly rotated, a new pattern with a much larger periodicity emerges. To date, research on such twisted bilayer structures2) has largely focused on two-dimensional materials such as graphene. In contrast, oxides are rigid three-dimensional crystals, making it challenging to fabricate twisted interfaces and selectively analyze interfacial structures. The research team solved this problem by utilizing the ‘coincidence site lattice (CSL)’ condition, in which atoms periodically coincide when two crystals are aligned at a specific angle. Applying this strategy to the oxide crystal strontium titanate (SrTiO3), the researchers discovered that the twisted oxide interface forms a moiré superlattice consisting of four distinct atomic configurations that repeat periodically. Even more strikingly, pronounced differences in electron distribution were observed only in specific atomic configurations. Subtle distortions in the oxygen octahedra, where six oxygen atoms surround a titanium atom, altered the number of oxygen atoms bonded to titanium. This change in local coordination dramatically modified electron behavior much like how the arrangement of furniture in a room influences people’s movement paths. In other words, differences in atomic arrangement alone led to completely different electron accumulation or depletion patterns, a phenomenon described by the researchers as charge disproportionation. To directly identify where and how this charge disproportionation occurs, the team employed an advanced depth-sectioning microscopy technique capable of adjusting the focal depth with angstrom-scale precision (1 Å = 10-10 m). This approach enabled experimental visualization of how atomic configurations and electronic behavior are correlated across the entire interface. Prof. Si-Young Choi of POSTECH remarked, “This work represents a significant advance by extending the field of twisted bilayer research which was previously confined to two-dimensional materials into three-dimensional oxide systems,” adding, “In the future, the twist angle itself may become a key design parameter for controlling atomic and electronic structures in electronic devices and functional materials.” This research was supported by the Ministry of Education (Korea Basic Science Institute and the National Research Facilities and Equipment Center) and the Ministry of Science and ICT through the National Research Foundation of Korea (Individual Basic Research Program). ▶️ DOI: http://doi.org/10.1021/acsnano.5c11685 1. Moiré pattern: An interference pattern that becomes visible or measurable when two periodic structures are overlapped with a slight mismatch or rotation between them. 2. Twisted bilayers: Crystalline systems in which two layers are stacked with a finite twist angle between them.

A Single Plate Captures Multiple Frequencies at Once

Professor Junsuk Rho’s Team Develops the World’s First Multi-Frequency Elastic Wave Control Technology It has long been considered common sense that a single device performs only one function. Just as tuning a radio to a different frequency changes the channel, systems that manipulate waves have traditionally been designed to operate at only one specific frequency, requiring different devices for different frequencies. Now, however, researchers have opened up a new possibility: a single thinplate can simultaneously distinguish elastic waves of multiple frequencies and precisely direct each of them to different locations. A research team led by Professor Junsuk Rho of the Department of Mechanical Engineering, Department of Chemical Engineering, Department of Electrical Engineering, and the Graduate School of Convergence Science and Technology at POSTECH, together with integrated PhD student Geon Lee and Dr. Wonjae Choi of KRISS, has developed the world’s first “frequency-multiplexed elastic metasurface.” This technology successfully enables simultaneous control of elastic waves at multiple frequencies without relying on complex structures and was recently published in the international journal Nature Communications. The research began with a focus on elastic waves—vibrations that propagate through structures when they are mechanically excited. Elastic waves are widely used in non-destructive testing, a technique that evaluates the condition of structures such as buildings and machinery without causing damage. However, even small changes in frequency can significantly alter wave speed and mode shape, making precise control extremely challenging. As a result, conventional technologies have been limited to handling only a single frequency with a given structure. Much like a radio can clearly receive only one channel at a time, mechanical systems have been designed to operate optimally at a specific frequency. When exposed to other frequencies, the intended functionality often breaks down. The research team addressed this limitation by focusing on a seemingly simple parameter: plate thickness. When elastic waves propagate through a thin plate, their phase—that is, their arrival timing—depends sensitively on the plate’s thickness. The team recognized that by carefully tailoring the thickness profile, it would be possible to induce completely different responses for different frequencies. This principle is analogous to how a prism separates white light into a rainbow by bending each wavelength at a different angle. Overall concept and demonstration of a dispersion-engineered elastic metasurface. (a) Schematic of frequency multiplexing achieved by comining phase profiles derived from plate theory with wavefront-engineered phase control. (b) Photograph of the fabricated elastic metasurface that selectively focuses elastic waves at different frequencies. (c) Results showing elastic waves being focused at distinct spatial locations depending on frequency. Based on this idea, the researchers first designed the target focal positions for each frequency and then implemented them in a physical plate structure. As a result, a single metasurface was able to precisely focus elastic waves at distinct frequencies—40 kHz, 60 kHz, and 80 kHz—onto different spatial locations. By placing piezoelectric elements at these focal points to convert mechanical vibrations into electrical signals, the team demonstrated that the signal intensity at a target frequency could be enhanced by up to 48 times compared to other frequencies. This clearly demonstrated that frequency information can be separated and read out using only a single thin metal plate. The significance of this technology lies in its integration of processes that previously required multiple devices and complex measurement systems. Wave control, frequency separation, spatial routing, and electrical signal conversion are all realized within a single metasurface structure. Professor Junsuk Rho stated, “This work represents a technological turning point that breaks the conventional belief that one structure can perform only one function.” He added, “Without the need for expensive equipment, this platform enables frequency-selective detection and amplification of structural vibrations, making it a core technology with broad potential applications in industry, defense, energy, and sensing.” This research was supported by the POSCO Holdings N.EX.T Impact Program, the Mid-Career Researcher Program of the NRF funded by the Ministry of Science and ICT, the Presidential Science Scholarship, the Hyundai Motor Chung Mong-Koo Foundation Fellowship, and the NRF/Ministry of Education Graduate Student Support Program in Science and Engineering. ▶️ DOI: https://doi.org/10.1038/s41467-025-65699-8

Steatotic Liver Disease Precisely Assessed Using Three-Dimensional Ultrafast Vascular Ultrasound

[POSTECH Researchers Enhance Diagnostic Performance for Steatotic Liver Disease Through Ultrafast Ultrasound Microvascular Flow Imaging] Steatotic liver disease (commonly called fatty liver disease) progresses silently. Even in the absence of noticeable symptoms, changes begin to unfold inside the liver. While hepatic fat accumulation remains a defining feature of the disease, steatotic liver disease is increasingly recognized as a multifactorial condition involving metabolic dysfunction and other interacting pathological processes. The key challenge lies in how early and how accurately these changes can be detected. Recently, researchers at POSTECH have successfully visualized the liver’s internal vascular network using ultrasound, opening a new avenue for earlier and more precise assessment of steatotic liver disease. Steatotic liver disease is the most common chronic liver disease worldwide. It typically begins with fat accumulation and can progress to inflammation, liver fibrosis, cirrhosis, and ultimately hepatocellular carcinoma, underscoring the importance of early detection and longitudinal monitoring. Conventional ultrasound, widely used in clinical practice, offers the advantage of conveniently assessing hepatic fat accumulation. However, its diagnostic performance is limited by operator dependency and reduced accuracy compared with magnetic resonance imaging (MRI). To overcome these limitations, the POSTECH research team led by Professors Chulhong Kim and Yong-Joo Ahn focused on subtle microvascular changes that emerge during the progression of steatotic liver disease. The team developed an ultrasound-based technology capable of three-dimensionally visualizing the liver’s vascular architecture. Much like observing urban traffic flow from a satellite, this approach enables real-time visualization of vascular alterations, including vessel obstruction and structural distortion. At the core of this technology is ultrafast Doppler imaging (UFD*1), which acquires thousands of ultrasound frames per second to precisely capture blood flow even within vessels thinner than a human hair. This was combined with established ultrasound techniques for evaluating hepatic fat accumulation and tissue structure, including attenuation imaging (ATI*2) and acoustic structure quantification (ASQ*3). Together, these components form a three-dimensional, multiparametric ultrasound imaging system that simultaneously integrates vascular and tissue information. Overview of a Three-Dimensional Multiparametric Ultrasound Imaging System for the Diagnosis and Monitoring of Steatotic Liver Disease Using this system, the researchers longitudinally tracked steatotic liver disease progression over an eight-week period. They successfully visualized three-dimensional changes in both hepatic tissue and microvasculature, demonstrating high reproducibility and robustness. Notably, the system also captured the restoration of vascular and tissue indices during disease recovery, highlighting its potential utility for evaluating therapeutic response and predicting prognosis. Quantitative analysis revealed a strong correlation between vascular indices and the degree of hepatic steatosis. By integrating multiple ultrasound-derived parameters using machine learning techniques, the researchers derived a comprehensive ultrasound score that classified steatotic liver disease severity with an average accuracy of 92%. Professor Chulhong Kim stated, “Ultrafast Doppler-based ultrasound imaging extends beyond conventional tissue-centered diagnosis by directly incorporating microvascular changes into clinical assessment, offering substantial diagnostic value.” Professor YongJoo Ahn added, “By enabling early detection and utilization of microvascular alterations, this approach opens new possibilities for precision medicine and holds promise for broader application across various liver diseases.” This study was conducted by research teams led by Professor Chulhong Kim (Departments of Electrical Engineering, IT Convergence Engineering, Mechanical Engineering, and the Graduate School of Convergence Science and Technology) and Professor Yong-Joo Ahn (Department of IT Convergence Engineering and the Graduate School of Convergence Science and Technology) at POSTECH. The findings were recently published in the international journal Nature Communications. This work was supported by the Ministry of Education, the Ministry of Science and ICT, and the Ministry of Health and Welfare of Korea. ➡️ DOI: https://doi.org/10.1038/s41467-025-65046-x 1. UFD(ultrafast Doppler imaging): An ultrasound imaging technique that acquires images at ultrafast frame rates, on the order of thousands of frames per second, enabling high-sensitivity visualization of microvascular blood flow that is difficult to observe with conventional Doppler ultrasound techniques. 2. ATI(attenuation imaging): A quantitative ultrasound method that measures the degree of ultrasound signal attenuation to assess the level of hepatic fat accumulation (steatosis) within the liver. 3. ASQ(acoustic structure quantification): A technique that quantitatively evaluates microstructural changes in liver tissue by analyzing the statistical distribution of ultrasound backscattered signals.

Mid-infrared Photoacoustic Polarization Uncovers Fiber Alignment in Heart Tissue

[POSTECH Team Pioneers Label-Free Mid-Infrared Dichroism-Sensitive Photoacoustic Microscopy for Quantitative Analysis of Tissue Microstructure] A research team at POSTECH has developed a new imaging technique that can analyze the structural health of tissues, such as the heart and tendons, without any staining. The method quantitatively measures the alignment and organization of protein fibers, offering a novel approach for diagnosing fibrosis, evaluating engineered tissues, and advancing regenerative medicine. The research was conducted by Professor Chulhong Kim (Department of Electrical Engineering, Department of Convergence IT Engineering, Department of Mechanical Engineering, Department of Medical Science and Engineering, Graduate School of Artificial Intelligence) and Professor Jinah Jang (Department of Mechanical Engineering, Department of Convergence IT Engineering, Department of Medical Science and Engineering), along with doctoral candidate Eunwoo Park (Department of Convergence IT Engineering) and Dr. Dong Gyu Hwang (the Center for 3D Organ Printing and Stem Cells). The findings were published in the international optics journal, Light: Science & Applications. Healthy biological tissues such as cardiac muscle rely on highly aligned protein fibers to maintain mechanical strength and function—similar to how tightly twisted strands strengthen a rope. However, in conditions such as myocardial infarction, fibrosis, or cancer, this alignment deteriorates, leading to structural disorganization and tissue malfunction. Detecting such microscopic changes is essential, but traditional histological and immunofluorescent staining methods are labor-intensive, antibody-dependent, and prone to inconsistent, limiting objective assessment. To overcome these limitations, the POSTECH team developed a mid-infrared dichroism-sensitive photoacoustic microscopy (MIR-DS-PAM*1), a label-free imaging technique that reveals both chemical composition and structural anisotropy in tissue. When tissue is illuminated with mid-infrared light, proteins absorb specific wavelengths according to their molecular bonds. By adding polarization control to this process, MIR-DS-PAM detects vectorial absorption linked to fiber alignment, enabling quantitative analysis of microstructural organization. Schematic illustration of structural analysis of engineered heart tissue using label-free mid-infrared dichroism-sensitive photoacoustic microscopy The team demonstrated the technique using engineered heart tissues. As the tissue matured, MIR-DS-PAM detected increasing protein accumulation and progressive alignment in extracellular matrix proteins, particularly collagen fibers. Furthermore, in fibrosis models, the system clearly distinguished healthy tissue with organized fibers from diseased tissue with disrupted architecture, achieving a strong correlation with fluorescence microscopy while eliminating the need for dyes or labeling. Professor Chulhong Kim remarked, “MIR-DS-PAM provides reliable and quantitative structural information in a label-free manner, comparable to fluorescence microscopy.” Professor Jinah Jang added, “This technique will greatly accelerate research in engineered tissues and disease modeling as it allows comprehensive tissue evaluation.” This research was made possible with support from the Ministry of Education, the Ministry of Science and ICT, the Korea Medical Device Development Fund, the Korean Fund for Regenerative Medicine, and the BK21 FOUR. ➡️DOI: https://doi.org/10.1038/s41377-025-02117-0 1) MIR-DS-PAM : Mid-infrared dichroism-sensitive photoacoustic microscopy

Anode-Free Battery Doubles Electric Vehicle Driving Range

[POSTECH, KAIST, and Gyeongsang National University achieve a record-breaking energy density of 1,270 Wh/L] Could an electric vehicle travel from Seoul to Busan and back on a single charge? Could drivers stop worrying about battery performance even in winter? A Korean research team has taken a major step toward answering these questions by developing an anode-free lithium metal battery that can deliver nearly double driving range using the same battery volume. A joint research team led by Professor Soojin Park and Dr. Dong-Yeob Han of the Department of Chemistry at POSTECH, together with Professor Nam-Soon Choi and Dr. Saehun Kim of KAIST, and Professor Tae Kyung Lee and researcher Junsu Son of Gyeongsang National University, has successfully achieved a volumetric energy density of 1,270 Wh/L in an anode-free lithium metal battery. This value is nearly twice that of current lithium-ion batteries used in electric vehicles, which typically deliver around 650 Wh/L. The achievement was published as a Front Cover article in Advanced Materials. An anode-free lithium metal battery eliminates the conventional anode altogether. Instead, lithium ions stored in the cathode move during charging and deposit directly onto a copper current collector. By removing unnecessary components, more internal space can be devoted to energy storage, much like fitting more fuel into the same-sized tank. However, this design comes with serious challenges. If lithium deposits unevenly, sharp needle-like structures known as dendrites can form, increasing the risk of short circuits and potential safety hazards. Repeated charging and discharging can also damage the lithium surface, rapidly shortening battery life. To address these issues, the research team adopted a dual strategy combining a Reversible Host (RH) and a Designed Electrolyte (DEL). The reversible host consists of a polymer framework embedded with uniformly distributed silver (Ag) nanoparticles, guiding lithium to deposit in designated locations rather than randomly. In simple terms, it acts like a dedicated parking lot for lithium, ensuring ordered and uniform deposition. The designed electrolyte further enhances stability by forming a thin but robust protective layer composed of Li₂O and Li₃N on the lithium surface. This layer functions like a bandage on skin, preventing harmful dendrite growth while maintaining open pathways for lithium ions transport. When combined, the RH–DEL system delivered outstanding performance. Under high areal capacity (4.6 mAh cm⁻²) and current density (2.3 mA cm⁻²), the battery retained 81.9% of its initial capacity after 100 cycles and achieved an average Coulombic efficiency of 99.6%. These results enabled the team to reach the record-breaking 1,270 Wh/L volumetric energy density in anode-free lithium metal batteries. Importantly, this performance was validated not only in small laboratory cells but also in pouch-type batteries, which are closer to real-world electric vehicle applications. Even with a minimal amount of electrolyte (E/C = 2.5 g Ah⁻¹) and under low stack pressure (20 kPa), the batteries operated stably. This demonstrates strong potential for reducing battery weight and volume while lowering manufacturing burdens, significantly improving commercial viability. Professor Soojin Park commented, “This work represents a meaningful breakthrough by simultaneously addressing efficiency and lifetime issues in anode-free lithium metal batteries.” Professor Tae Kyung Lee added, “Our study demonstrates that electrolyte design based on commercially available solvents can achieve both high lithium-ion mobility and interfacial stability.” This research was supported by the Ministry of Science and ICT (MSIT) of Korea. DOI: https://doi.org/10.1002/adma.202515906