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SKKU's Interdisciplinary Team Led by Prof. Suk Ho Bhang (Dept of Chemical Engineering) and Prof. Jeeheon Jeong
A research team at Sungkyunkwan University, led by Professor Suk Ho Bhang of the Department of Chemical Engineering and at Gachon University, led by Professor TaeIl Lee of the Department of Materials Science and Engineering, has developed a novel 3D cell culture platform using a ‘Free-Standing (FS) Device,’ signaling a transformative leap in next-generation tissue regeneration and stem cell therapy. This technology enables rapid and highly efficient cell compaction and spheroidization, with its therapeutic potential validated in animal models. To overcome the complexity and time-consuming limitations of conventional 3D culture methods, the team engineered a levitated cell culture system using acoustic standing waves within a liquid medium. The FS Device suspends cells in mid-air, facilitating their autonomous assembly into dense, uniform spheroids. The foundational studies were previously published in Bioengineering & Translational Medicine (2022) and Biomaterials Research (2023). In the most recent advancement, Professors Suk Ho Bhang (Chemical Engineering) and Jeeheon Jeong (Medicine) collaborated to develop a new FS Device-based cell culture method aimed at significantly enhancing islet transplantation for Type 1 Diabetes Mellitus. This study achieved the formation of high-functionality heterotypic pseudo-islets (Hislets) within just 20 hours—dramatically reducing the 5+ days typically required for pseudo-islet formation. The findings were published in Bioactive Materials (Impact Factor: 18.9, JCR Top 1%) in May 2025. Paper Title: Subaqueous acoustic pressure system based one day heterotypic pseudo-islet spheroid formation with adipose derived stem cells for graft survival-related function enhancement First Authors: Dr. Jiyu Hyun, Mr. Junhyeong Park (Ph.D. candidate) Corresponding Authors: Prof. Hyun-ji Park, Prof. Dong Yun Lee, Prof. Jee-Heon Jeong, Prof. Suk Ho Bhang Journal: Bioactive Materials, Volume 51, Pages 276–292 DOI: 10.1016/j.bioactmat.2025.05.005
- No. 314
- 2025-06-18
- 303
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The Future of Humanity Unfolding Through ESG:
This study presents a significant advancement in Environmental, Social, Governance (ESG) evaluation by addressing critical gaps in transparency, consistency, and industry-specific relevance. The ESG-Keyword integrated bidirectional encoder representations from transformers (ESG-KIBERT) model, developed using advanced natural language processing (NLP) techniques, enhances ESG classification performance and sets a new standard for automated ESG analysis. With robust performance metrics, it supports reliable and consistent assessments across industries. Additionally, incorporating Sustainability Accounting Standards Board's materiality map offers a customized evaluation framework that accounts for industry-specific factors affecting corporate sustainability. Furthermore, the integration of sentiment analysis enriches ESG evaluations by capturing market and investor perceptions, contributing to a more transparent assessment. This study offers a comprehensive, standardized ESG evaluation framework that improves both the methodological rigor and practical utility of corporate sustainability assessments, enabling more informed decision-making for companies, investors and policymakers. *Title : ESG-KIBERT: A new paradigm in ESG evaluation using NLP and industry-specific customization *Journal : DECISION SUPPORT SYSTEMS *DOI : https://doi.org/10.1016/j.dss.2025.114440
- No. 313
- 2025-06-13
- 279
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A Fascinating Material That Changes with Oxygen
Most materials around us retain their properties once formed, but SrFeOx (strontium iron oxide) is an exception. This material drastically changes its properties depending on the amount of oxygen it contains — with x ranging from 2 to 3 — making it a highly intriguing subject of study. Professor Woo Seok Choi’s research team in the Department of Physics has developed this material in the form of thin single-crystal films and reported a series of significant findings. For instance, SrFeO2.5 adopts a layered structure called brownmillerite, which forms when oxygen is partially removed from SrFeO3, a material with a perovskite structure. The resulting structure features alternating layers of FeO6 octahedra and FeO4 tetrahedra and exhibits a distinctive electrical polarity — that is, a directional asymmetry. In this study, it was revealed that this structure shows ferroelectricity even at ultra-thin scales, down to a single atomic layer (as shown in the Figure below, see the first reference). Ferroelectricity is a key physical property for applications in memory and energy devices. This ferroelectric behavior originates solely in the FeO4 tetrahedral layers, while the FeO6 layers in between act like insulating spacers, minimizing interference between neighboring layers. As a result, each thin layer can switch its electric polarization independently — like stacking atomically thin electric switches — opening up exciting possibilities for next-generation ultra-compact memory devices. Meanwhile, further reducing the oxygen in SrFeO2.5 produces SrFeO2, which has a completely different structure known as the infinite-layer structure, where iron atoms are surrounded by oxygen only in two dimensions (see the second reference). This transformation is achieved by high-temperature treatment to remove oxygen atoms. In this study, researchers used real-time electron microscopy to directly observe how oxygen atoms escape along the layers, how iron atoms rearrange, and how the structure evolves step by step — all at the atomic scale. Surprisingly, this transformation happens very quickly, and the rate of change varies depending on the orientation of oxygen diffusion channels. In fact, the crystal structure can even rotate 90 degrees to align these channels in a direction that facilitates easier oxygen release. Thanks to this flexible yet precisely controlled structural behavior, SrFeOx is not only electrically active but also holds great potential for future optoelectronic devices involving magnetism, electrical conductivity, and even superconductivity. In essence, SrFeOx is an oxygen-tunable material whose structure and properties can be dramatically altered by adjusting its oxygen content — offering a key to creating faster, smaller, and more efficient electronic components in the near future. Reference [1] Sub-unit-cell-segmented ferroelectricity in brownmillerite oxides by phonon decoupling, Nat. Mater. https://doi.org/10.1038/s41563-025-02233-7 (2025). [2] Monitoring the formation of infinite-layer transition metal oxides through in situ atomic-resolution electron microscopy, Nat. Chem. https://doi.org/10.1038/s41557-024-01617-7 (2025).
- No. 312
- 2025-06-10
- 399
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If Quitting Is Too Hard, Could E-Cigarettes Be a Safer Option?
A recent Korean nationwide study published in the European Heart Journal (Impact Factor = 39.3) reports that patients who switch from combustible cigarettes to e-cigarettes after percutaneous coronary intervention (PCI), or who successfully quit smoking altogether, show significantly lower risks of cardiovascular complications. Using data from the National Health Insurance Service (NHIS), the study analyzed 17,973 adult smokers who underwent PCI. Participants were categorized into three groups: those who continued smoking combustible cigarettes, those who switched to e-cigarettes, and those who successfully quit smoking. The incidence of major adverse cardiovascular events (MACEs), including myocardial infarction, all-cause death, and repeat revascularization, was compared across these groups. The findings revealed that patients who entirely switched to e-cigarettes had an approximately 18% lower risk of MACEs compared with those who continued smoking combustible cigarettes. The reduction in risk was comparable to that observed in the complete smoking cessation group. Dr. Choi, the corresponding author emphasized the clinical implications: “Many patients continue to smoke even after suffering myocardial infarction, which increases the risk of stent thrombosis and other fatal complications. While smoking cessation is the best option, switching to less harmful alternatives such as e-cigarettes may be a pragmatic secondary approach for those unable to quit.” This publication is also a compelling example of interdisciplinary collaboration between physician and epidemiologist. The study was co-led by Prof. Ki Hong Choi (Cardiology, SKKU School of Medicine and Samsung Medical Center) and Prof. Danbee Kang (Department of Clinical Research Design & Evaluation, Samsung Advanced Institute for Health Sciences & Technology, SAIHST). Together, the team has consistently addressed clinical questions using diverse methodological approaches. Their efforts include numerous joint publications in top-tier journals with impact factors exceeding 10, including articles ranked in the top 5% of their respective fields. Beyond this study, they continue to lead a broad spectrum of projects that translate bedside questions into evidence through real-world data. Their work spans from evaluating treatment effectiveness to assessing health system interventions, all while maintaining a practical, patient-centered perspective.
- No. 311
- 2025-06-04
- 540
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Adhesive Cortical Device Enables Artifact-Free Neuromodulation for Closed-loop Epilepsy Treatment
Epilepsy, a neurological disorder affecting over 65 million people worldwide, is characterized by pathological electrical hyperactivity in the brain resulting in seizures. Notably, approximately 20-30% of all patients are diagnosed with intractable epilepsy, which does not respond to standard medications. Surgical resection of lesions remains a treatment option for these patients, but it presents challenges due to the complexity and risks involved in the procedure. As a less invasive alternative treatment, the concept of neuromodulation has been proposed, which involves directly stimulating lesioned tissue with mechanical, electromagnetic, or optical energy to suppress brain hyperexcitability. One promising approach is transcranial focused ultrasound (tFUS) neurostimulation, a non-invasive method that stimulates the brain with high precision without causing permanent damage. For tFUS to be effective in treating epilepsy, it must be paired with a system that can continuously monitor brain activity and adjust the treatment in real-time. However, existing cortex-interfacing devices face challenges due to their high stiffness and low shape adaptability, which makes it difficult for them to conform to the convoluted surface of the brain, resulting in poor tissue-device interfaces. Their low adhesion to the brain surface also means they struggle to provide accurate brain signals during ultrasound stimulation, due to the interference caused by the mechanical pressure waves. To address this challenge, the research team developed the Shape-Morphing Cortical-Adhesive (SMCA) sensor, a soft, flexible device that adheres closely to the brain’s surface, ensuring stable and accurate monitoring of brain activity even during tFUS stimulation. The SMCA sensor is composed of a unique combination of materials. It features a layer of catechol-conjugated alginate hydrogel that quickly bonds with brain tissue, providing strong adhesion and reducing the risk of movement or detachment. Additionally, the device’s substrate is made of a self-healing polymer that softens and conforms to the brain’s curved surface at body temperature, ensuring a snug fit and minimizing the risk of signal artifacts. The team tested the SMCA sensor both ex vivo (outside the body) and in vivo (inside the body), comparing its performance to that of existing devices without adhesive or shape-morphing properties. In experiments with a rat model of epilepsy, the SMCA sensor successfully recorded brain activity during tFUS without interference, enabling the real-time monitoring necessary for effective treatment. Using this innovative sensor, the researchers implemented a closed-loop seizure control system. This system uses the SMCA sensor to detect early signs of a seizure and automatically adjusts the tFUS treatment in response. The system successfully suppressed seizures in real-time, demonstrating the potential for personalized, adaptive epilepsy treatment. Professor SON Donghee stated, “Through our study on the brain-adhesive soft bioelectronics platform, we have overcome a major challenge in the field of brain interfaces by achieving high-quality electrocorticography coupled with focused ultrasound stimulation without artifact interference.” He explained the significance of this research and outlined future plans by adding, “We expect our technology to become a cornerstone of a next-generation biomedical platform that enables precise diagnosis and personalized therapy for intractable neurological disorders. Following this study, we will advance the SMCA sensor platform by improving the shape-morphing and cortex-adhesive functionalities, developing highly integrated microelectrodes, and implementing a high-order closed-loop operational algorithm.”. Dr. Hyungmin KIM stated, “We achieved early detection of seizure activity via ECoG, enabling the prevention of seizures. Additionally, we implemented real-time feedback on the effects of ultrasound stimulation, which allowed for the application of personalized stimulation protocols. Looking ahead, we anticipate that the development of electrodes with more channels, as well as multi-channel ultrasound transducers, will facilitate precise mapping of seizure sources and targeted intervention, ultimately enhancing the efficacy and safety of this approach in clinical applications.” This research was conducted in collaboration with colleagues from Sungkyunkwan University (SKKU) and the Korea Institute of Science and Technology (KIST). The findings were published in Nature Electronics on Month Day, 2024. Figure 1. Overview and operation principle of a shape-morphing cortex-adhesive (SMCA) sensor A schematic illustration for exploded view of a SMCA sensor. B. A schematic illustration for a SMCA sensor mounted conformally on a rodent’s brain tissue. (Inset) a photoimage illustrating robust tissue adhesion of a SMCA sensor on a rat’s cortex under shear strain. C. Schematic illustrations of sequential brain-interfacing steps of the SMCA sensor for explaining the tissue-adhesive shape-morphing mechanism. Figure 2. Brain interfacing functionalities of SMCA soft patches Comparison of the tissue-adhesive strength between Alg and Alg–CA according to stretching direction. Both hydrogel materials were coupled with the SHP substrate. b. Plot of relative storage modulus of thermoset PDMS (red) and thermoplastic SHP (blue) films as a function of temperature. (Inset) showing the magnified view of the plot ranging from room temperature (25℃) to body temperature (37℃). C. Strain‒stress curves of PDMS (red) and SHP (blue) films. D. Comparative photoimages illustrating tissue-adhesion performances of Alg/SHP (top), Alg–CA/PDMS (middle), SMCA (bottom) films on bovine brain while shear strain was applied. E. Comparative sequential images of Alg–CA/PDMS (top) and SMCA (bottom) mounted on bovine brain tissue with curved surface morphology illustrating behaviour of soft films over time. The surface temperature of the brain tissue was set at 37 °C. Figure 3. SMCA sensor allows for artefact-free neural recording Schematic image of the in vivo test for neural recording performance. M, motor; S, somatosensory; C, cingulate; R, retrosplenial; P, posterior parietal; V, visual; B, bregma; Ref, reference; Gnd, ground; b-e. Top-view images and corresponding timetrace plots of cortical activity from a representative trial of brain-mounted soft ECoG devices combined with 4 different materials, including PDMS (b). SHP (c). Alg (interface)/SHP (substrate) (d). and SMCA (SMCA sensor) (e). Magnified data plots of three consecutive channels, including a channel located on the visual cortex of the left hemisphere (Ch.15) directly stimulated by tFUS of each material platform. Figure 4. Closed-loop seizure control system capable of apposite tFUS modulation utilizing neurosignal feedbaa. An illustration of the customized headstage system incorating with the SMCA sensor and a tFUS transducer for closed-loop neural recording and feedback neurostimulation. (Inset) A corresponding image shows the portable closed-loop therapeutic system applied to an awake freely moving rat. b. Schematics and corresponding conceptual plots of neural signals from the soft ECoG devices (top, the conventional device without tissue adhesion and conformability; bottom, the SMCA sensor) as a function of time under tFUS stimulation. c. Schematic illustrations of conceptual ECoG plot recorded from the SMCA sensor during closed-loop tFUS seizure suppression in an awake rodent model. d. Timetrace plot of 16-channel ECoG signals recorded from the SMCA sensor for a case of closed-loop seizure control based on 3-level tFUS protocol modulation, applied to the awake epileptic rodent model. e. Detailed ECoG trace from single-channel in the SMCA sensor during closed-loop seizure control. Magnified plots show 5-sec cropped neural activities corresponding to major phase of seizure epoch during closed-loop tFUS neurostimulation.
- No. 310
- 2025-05-30
- 594
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Develops High-Performance Membranes for Energy-efficient Crude Oil Fractionation towards Carbon Neutrality
Sungkyunkwan University (SKKU, President: Ji-Beom Yoo) announced that Professor Tae Hoon Lee’s research team from the Department of Future Energy Engineering, in collaboration with researchers from the Massachusetts Institute of Technology (MIT), has developed a high-performance ultramicroporous membrane* capable of replacing conventional crude oil refining processes. The study was published in the May 23 issue of the international journal Science. *Membrane: A membrane is a functional material that selectively allows or blocks the passage of specific molecules based on size, shape, or chemical properties. Membrane-based separations require neither heat energy nor phase changes, offering a promising alternative to conventional, energy-intensive separation methods such as distillation. Currently, crude oil refining primarily relies on thermal distillation, which accounts for approximately 1% of global energy consumption and 6% of CO2 emissions, making it highly energy-intensive. Although polymer membranes based on Polymers of Intrinsic Microporosity (PIMs)** have been explored as an alternative, their commercialization has been hindered by high costs, low selectivity, and susceptibility to swelling and plasticization when exposed to organic solvents. **Polymers of Intrinsic Microporosity (PIMs): These novel materials feature rigid and contorted molecular structures that prevent dense packing of polymer chains, creating abundant free volume and sub-nanometer pores (<2 nm in size, BET surface area >100 m²/g). To overcome these challenges, the research team replaced the conventional amide bonds found in commercial reverse osmosis membranes with imine bonds***, which offer superior resistance to swelling and lower polarity, thereby achieving both structural rigidity and ultramicroporosity. Furthermore, the incorporation of triptycene and spirobifluorene units enhanced the membrane’s resistance to swelling and plasticization, as well as its molecular selectivity. Notably, the membranes were fabricated using interfacial polymerization, an industrially validated process suitable for large-scale manufacturing. ***Imine bond: Formed via a condensation reaction between an amine (-NH2) and an aldehyde (-CHO), the imine (C=N) bond is less polar and structurally more rigid than amide bonds. Experimental results demonstrated that the new membranes can selectively separate fuel components based on molecular size, potentially reducing energy consumption by tens of percent compared to traditional distillation—a feature unattainable with existing commercial membranes. Professor Tae Hoon Lee, the study’s first author, stated, “The ultramicroporous imine-based membranes we developed show groundbreaking potential to replace conventional thermal separation processes, potentially reducing the energy required for crude oil fractionation by up to several tens of percent. By leveraging an interfacial polymerization method compatible with industrial manufacturing, this technology not only promises scalability but also contributes to decarbonizing the petrochemical industry and could transform the future paradigm of eco-friendly fuel production and refining.” This research was supported by the MIT Energy Initiative (MITEI) and the King Abdullah University of Science and Technology (KAUST) and was published in the May 23 issue of Science. ※ Paper Title: Microporous polyimine membranes for efficient separation of liquid hydrocarbon mixtures ※ Journal: Science ※ Authors: Corresponding Author: Zachary P. Smith; First Author: Tae Hoon Lee; Co-authors: Zain Ali, Taigyu Joo, Matthew P. Rivera, Ingo Pinnau ※ DOI: 10.1126/science.adv6886 (forthcoming) ▲Schematic Diagram of the Fabrication and Applications of Ultra-Microporous Separation Membranes via Acid-Catalyzed Interfacial Polymerization
- No. 309
- 2025-05-26
- 678
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Multifunctional MXene-CNT Janus Film Enables Durable EMI and Infrared Shielding/Detection in Extreme Environments
Professor Chong Min Koo's research team from the School of Advanced Materials Science and Engineering at Sungkyunkwan University, in collaboration with Professor Youngjin Jeong at Soongsil University, has developed a flexible, lightweight, and robust Janus film composed of MXene and carbon nanotubes (CNTs). This advanced hybrid materials demonstrates exceptional electromagnetic interference (EMI) shielding and infrared (IR) shielding/detection capabilities, even under extreme conditions ranging from cryogenic to high temperatures. The study, led by first author Dr. Tufail Hassan, was published in the prestigious journal Nano-Micro Letters (Impact Factor: 31.6). Modern defense, aerospace, and electronic applications demand ultrathin, flexible, and multifunctional materials capable of operating under harsh environmental stressors. Traditional EMI shielding materials like copper, while effective, suffer from drawbacks including high weight, corrosion susceptibility, and limited processability. MXenes—2D materials known for high electrical conductivity and low IR emissivity—present a promising alternative, but their application is hindered by oxidation sensitivity and mechanical fragility. To address the limitations of conventional MXene materials, the team synthesized highly crystalline, oxidation-resistant Ti₃C₂Tₓ MXene and integrated it with a mechanically robust carbon nanotube (CNT) film through hydrogen bonding to create a Janus architecture. The resulting 15 µm-thick Janus film demonstrated exceptional multifunctionality, including an EMI shielding effectiveness of 72 dB in the X-band, ultralow IR emissivity of 0.09, and high IR detection sensitivity, evidenced by a 44% increase in resistance under 250 W IR exposure. Importantly, the film maintained its structural and functional integrity after 300 bending cycles and 30 thermal shock cycles across a 396 °C temperature range, significantly outperforming conventional MXene- or polymer-based materials in durability, electrical performance, and thermal camouflage. Fabricated via a scalable vacuum-assisted filtration method, the Janus film is well-suited for industrial-scale production. Its asymmetric design enables dual-mode operation: the MXene side provides efficient IR reflection for stealth functionality, while the CNT side enables high-sensitivity IR detection—making it highly suitable for next-generation military, aerospace, and wearable sensing technologies. This work establishes a new benchmark for multifunctional shielding materials and paves the way for resilient, adaptive systems capable of withstanding extreme environmental conditions. This study was financially supported by grants from the Basic Science Research Program (2021M3H4A1A03047327 and 2022R1A2C3006227) through the National Research Foundation of Korea, funded by the Ministry of Science, ICT, and Future Planning, Republic of Korea; and the National Research Council of Science & Technology (NST), funded by the Korean Government (MSIT) (CRC22031-000). Paper title: Multifunctional MXene/Carbon Nanotube Janus Film for Electromagnetic Shielding and Infrared Shielding/Detection in Harsh Environments Journal: Nano-Micro Letters DOI: https://doi.org/10.1007/s40820-024-01431-3 Figure 1: A schematic illustration highlights the film’s excellent mechanical strength, electromagnetic interference shielding, infrared shielding/detection capabilities, and remarkable retention of performance even after repeated bending cycles and thermal shock with a temperature difference of 396 °C.
- No. 308
- 2025-05-21
- 786
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Development of a Convenient Method for Evaluating the Properties of a Two-Dimensional Amorphous Material
A research team led by Professor Changgu Lee of the School of Mechanical Engineering and Dr. Kyuyoun Won of the IBS Center for Two-Dimensional Quantum Heterostructures, in collaboration with Professor Jong-Hoon Lee of UNIST, has devised a breakthrough optical technique that allows the convenient evaluation of the properties of two-dimensional (2D) materials with almost no long-range crystallinity. Discovered in 2004, graphene—which earned its discoverers a Nobel Prize—sparked intense research into 2D materials, all of which were found and studied in crystalline forms with well-ordered atomic lattices. The better the crystallinity, the superior the mechanical strength, electrical conductivity, and thermal conductivity. For this reason, various 2D materials such as boron nitride and molybdenum disulfide have been explored since graphene’s discovery, while amorphous (non-crystalline) 2D materials have received almost no attention. Recently, however, a 2D amorphous carbon material, the non-crystalline counterpart of graphene, has been synthesized, and fundamental research has begun in earnest. Although amorphous 2D materials generally exhibit inferior properties compared with their crystalline counterparts, they can reveal entirely unexpected phenomena and provide decisive clues to structural issues in existing three-dimensional amorphous materials, opening diverse avenues for application. For example, traditional amorphous insulators such as silicon oxide—used in semiconductor processes—face physical limits as memory and CPU circuits continue to shrink, because device-to-device interference grows severe at high operating speeds. Amorphous 2D materials, however, have been shown to combine mechanical stability with an ultralow dielectric constant, drastically reducing interference and making them strong candidates for next-generation semiconductor fabrication. Yet their dielectric and physical properties vary with synthesis conditions, posing challenges for commercial production. Precise characterization has required expensive instrumentation such as transmission electron microscopy (TEM) and advanced analysis skills, inevitably slowing research and development. Professor Lee’s team has developed an easy optical method to analyze the lattice structure and properties of 2D amorphous carbon. Previously, such films were grown on metallic substrates like copper foil, but spectroscopic analysis was practically impossible because of noise from the metal. Transferring the films onto non-metallic substrates introduced contamination that hindered accurate measurements. Consequently, studies relied almost exclusively on costly TEM, creating a high barrier to entry. The team solved this by inventing a direct-growth technique on non-metallic substrates and by comparing Raman and X-ray spectroscopy with TEM results, proving that inexpensive, user-friendly Raman spectroscopy alone can reliably characterize these materials. Because Raman tools are readily accessible to materials researchers and cost one-tenth to one-hundredth of TEM analysis, the team’s method dramatically lowers the hurdle for studying 2D amorphous materials. Looking ahead, this analytical approach is expected to be applicable to 2D-material-based memory, logic, and AI devices. As silicon miniaturization reaches its limits around 2030, the method could become a key technique for the emerging 2D-material semiconductor industry, which is anticipated to replace silicon. Authors: Dr. Kyuyoun Won, Professor Jong-Hoon Lee, Jongchan Yoon (co-first author), Dohyun Jeon, Jinhwan Hong, Hyunggu Yoo, Yeji Bang Pawan Kumar Srivastava, Budhi Singh, Professor Jong-Hoon Lee, Professor Changgu Lee Journal: Spectroscopic signatures of ultra-thin amorphous carbon with the tuned disorder directly grown on a dielectric substrate (Advanced Materials; IF=27.4, December 2024)
- No. 307
- 2025-05-19
- 606
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Developement of an 'Intelligent Artificial Tactile Receptors' Mimicking Biological Tactile Organs
A research team led by Professor Nae-Eung Lee from the Department of Advanced Materials Science and Engineering at Sungkyunkwan University (President: Juy-Beom Yoo) has developed an intelligent artificial tactile receptor* array*, inspired by the human tactile perception system and mimicking the function and structure of biological synapses. Based on this achievement, the team has also implemented a new intelligent sensor platform. * Tactile receptor: A sensory component that detects external stimuli (such as pressure, vibration, or temperature) and converts them into action potentials to be transmitted to the brain. * Array: A structure composed of multiple elements designed to operate collectively, rather than as a single unit. The importance and role of artificial intelligence (AI) have recently garnered attention across all industrial sectors. In particular, Physical AI is emerging as a core foundational technology for autonomous systems in future industries. In Physical AI, data input begins with sensors, and accordingly, active research is underway on intelligent sensor technologies that mimic the high-performance signal processing mechanisms of the human somatosensory system, enabling efficient processing of sensor data. This study focused on how the human sensory system initially processes information - specifically, on the "synapse-like structure" between sensory receptors and nerve endings. Inspired by both slowly adapting (Merkel) and fast adapting (Pacinian) tactile receptors in human skin, the research team developed an integrated platform that combines 16 sensory array and synaptic transistors, incorporating both types of adaptive responses. This platform integrates a triboelectric sensor layer, designed to resemble a human fingerprint, with synaptic transistors that can memorize and respond to stimuli as all-in-one structure. It is capable of simultaneously recognizing both slow and fast stimuli. Experimental results demonstrated that the sensor naturally modulates synaptic weights in response to variations in the intensity, frequency, and type of mechanical stimuli. Notably, the system was able to recognize textures and surface patterns with over 90% accuracy using less than 10% of the total data, indicating significantly higher data processing efficiency compared to conventional technologies. Such sensors, which incorporate AI functionality directly into the sensing mechanism itself, are characterized by ultra-low voltage and ultra-low power operation with high efficiency. They open new technological possibilities across various fields, including intelligent robotics, neuromorphic sensory systems, and wearable electronic skin. In particular, their ability to process environmental data at the sensor level positions them as a key enabling technology for the future development of high-speed, energy-efficient autonomous AI systems. This research was supported by the Ministry of Science and ICT through the Mid-career Researcher Program and the Nano and Material Technology Development Program, as well as by the Ministry of Education through the Basic Research Infrastructure Support Program (Focused Research Institute Support Project). The study was conducted by Seokju Hong (integrated M.S.-Ph.D. student), Dr. Yurim Lee, and Dr. Atanu Bag as co-first authors, under the supervision of Professor Nae-Eung Lee as the corresponding author. The results of this research were published on April 28, 2025, in Nature Materials, the world’s leading journal in the field of materials science. ※Title: Bio-inspired artificial mechanoreceptors with built-in synaptic functions for intelligent tactile skin ※Journal: Nature Materials ※Authors: Nae-Eung Lee(Corresponding author), Seokju Hong, Yurim Lee, Atanu Bag (co-first authors), Hyosoo Kim, Trang Quang Trung, M Junaid Sultan, Dong-bin Moon (co authors) Development of Ultra-high Efficiency, Ultra-low Power, Intelligent Artificial Tactile Receptors Mimicking Slowly and Fast Adapting Tactile Receptors (from left) Nae-Eung Lee(Corresponding author), Seokju Hong, Yurim Lee, Atanu Bag
- No. 306
- 2025-05-14
- 792
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Vertical DNA Patterning with Nano-Scale Precision for Advanced Biosensing
Professor Dong-Hwan Kim and his research team in the School of Chemical Engineering at Sungkyunkwan University, in collaboration with Dr. Yoojin Oh and Professor Peter Hinterdorfer from Johannes Kepler University Linz, have developed an innovative vertical DNA nanopatterning platform through international joint research. The team successfully harnessed the self-assembly properties of DNA tile-based nanostructures to create uniform, high-density surfaces with multiple receptor sites across large areas. By introducing a stepwise growth process that includes low-temperature annealing, they achieved precise control over the spacing and density of vertically aligned DNA structures, attaining surface coverage rates exceeding 98%. To demonstrate functional applicability, the team introduced thrombin-binding aptamers (TBA15) onto the vertical structures, enabling selective target binding and fluorescence signal generation. The results showed a significant enhancement in surface sensitivity and uniformity, making the platform suitable for applications in surface plasmon resonance (SPR), atomic force microscopy (AFM), and high-throughput biosensing. The precise spacing between receptors reduces the effects of random orientation and signal variability, ensuring high reproducibility and signal-to-noise ratios. This study highlights the scalability of DNA nanotechnology for constructing functional surfaces with both nanoscale precision and macroscale uniformity. The newly developed vertical DNA array platform is expected to find broad utility in biosensors, advanced diagnostic devices, and optoelectronic systems.
- No. 305
- 2025-05-07
- 1020
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Exploring Psychological Similarities and Neurophysiological Differences in Internet Gaming and Alcohol Use Disorder
A collaborative research team led by Professor Jung-Seok Choi from the Department of Psychiatry at Samsung Medical Center, Sungkyunkwan University, and Professor Woo-Young Ahn from the Department of Psychology at Seoul National University has identified the shared and distinct psychological and neurophysiological characteristics of IGD and AUD using artificial intelligence techniques. This study was recently published in the Comprehensive Psychiatry, and the research was conducted by Ji-Yoon Lee (first author, Department of Healthcare and Convergence Science, Seoul National University) and Myeong Seop Song (co-first author, Department of Psychology, Seoul National University), among others. Substance use disorder typically involves the repeated use of substances that directly affect the body—most notably alcohol and drugs. In recent years, however, excessive engagement in certain behaviors such as gambling, gaming, and shopping has gained attention as another form of addiction, referred to as behavioral addiction. While the triggers may differ—substances versus behaviors—numerous studies have reported that substance use disorder and behavioral addiction share similarities in terms of clinical symptoms, disease progression, genetic underpinnings, and neural abnormalities. Based on these similarities, the 11th revision of the International Classification of Diseases (ICD-11) officially included "disorders due to addictive behaviors", and in 2018, both gambling disorder and gaming disorder were recognized as formal diagnoses by the World Health Organization. However, despite this recognition, the neurological basis of behavioral addictions remains insufficiently understood, and there is ongoing debate as to whether they should be considered brain disorders on par with substance addictions. This underscores the need to elucidate the neural mechanisms underlying behavioral addiction and determine how they overlap or diverge from those associated with substance addiction. In South Korea, one of the most prevalent behavioral addictions is IGD characterized by excessive and persistent use of online games. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) includes IGD as a condition warranting further study. Previous research has indicated that individuals with IGD often exhibit psychological symptoms such as depression, anxiety, and impulsivity, similar to those with AUD. However, the specific neural mechanisms that distinguish or connect these two disorders have not been fully clarified. Therefore, the present study aimed to compare the neurophysiological and psychological characteristics of IGD and AUD using a multimodal machine learning framework, integrating both EEG data and neuropsychological features. We analyzed both the neurophysiological and psychological characteristics of IGD and AUD using artificial intelligence models applied to multimodal data—resting-state EEG signals recorded with eyes closed, and standardized psychological assessments. A total of 191 participants were included in the study: 67 individuals with IGD, 58 with AUD, and 66 healthy controls. From the EEG data, the researchers extracted both sensor-level (channel-based) and source-level (brain-region-based) connectivity features. In parallel, they collected psychological data, including measures of depression, anxiety, impulsivity, and intelligence quotient (IQ). Three machine learning algorithms were used for classification: L1-norm logistic regression, support vector machines, and random forest. We compared models trained using EEG data alone, psychological data alone, and a multimodal model that integrated both. Figure 1. Multimodal analysis framework The multimodal L1-norm logistic regression model achieved the highest performance in distinguishing IGD from AUD, with a classification accuracy of 71.2%—surpassing the models with neuropsychogical or EEG data. Notably, the results revealed that connectivity differences in delta and beta frequency bands—particularly within the right orbitofrontal cortex, prefrontal cortex, temporal lobe, and anterior cingulate cortex—played a key role in distinguishing the two disorders. These regions are associated with reward processing and cognitive control, suggesting distinct patterns of neural dysfunction between IGD and AUD. In contrast, psychological features such as depression, anxiety, and impulsivity did not significantly differ between the two groups, highlighting that while IGD and AUD may share similar psychological profiles and exhibit distinct neurophysiological patterns. Figure 2. Feature importance according to beta coefficients: comparison between IGD and AUD This study is the first to compare behavioral addiction and substance use disorder using both non-invasive and cost-effective EEG data and neuropsychological assessments. It offers a potential technical foundation for the early diagnosis, personalized treatment, and potential development of digital therapeutics for addiction-related disorders. Moreover, the multimodal machine learning approach achieved high classification performance and shows great potential for broader application in the diagnosis and prognosis of various psychiatric conditions.
- No. 304
- 2025-04-28
- 1131
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Next-Gen Wearable Haptic Electronics for Immersive XR and Sensory Substitution
Professor Jaeyoung Yoo’s team, in collaboration with Professor John Rogers' group at Northwestern University, has developed a groundbreaking wireless, skin-attachable haptic interface that mimics the complexity of human touch. This research introduces the "Full Freedom-of-Motion (FOM) Actuator," a compact device capable of delivering multidirectional tactile stimuli—including pressure, vibration, stretching, sliding, and twisting—by precisely engaging various mechanoreceptors in the skin. Unlike conventional haptic technologies that primarily rely on unidirectional vibrations, the FOM actuator employs a nested configuration of electromagnetic coils and magnets to generate dynamic, programmable forces in all directions. This design enables the device to produce complex tactile sensations, offering a more realistic and immersive user experience in extended reality (XR) applications. The research team demonstrated the device's versatility through various applications. For instance, by attaching the haptic interface to different body parts such as the back of the hand, fingers, or arms, visually impaired users could receive navigation cues through tactile feedback, facilitating precise hand movements and object detection without visual input. Additionally, the device successfully replicated the textures of materials like fabric and metal, enhancing the realism of virtual object interactions. Notably, the team converted sound frequency information from musical instruments into distinct vibration patterns, allowing users to perceive musical components through touch alone, thereby offering a novel sensory substitution method for individuals with hearing impairments. The haptic platform is designed to be compact, lightweight, and capable of delivering high-resolution tactile feedback. It ensures a high data transmission rate per device and features wireless control via Bluetooth, along with a flexible material structure optimized for skin contact. These attributes make it a promising tool for various applications, including XR-based gaming, medical training, rehabilitation, and sensory assistive devices. Professor Jaeyoung Yoo remarked, “This research demonstrates the potential of advanced actuator technology capable of physically stimulating diverse tactile receptors. It offers promising applications not only as assistive technology for individuals with sensory impairments but also as a core interface for more immersive XR experiences.” The study, titled “Full freedom-of-motion actuators as advanced haptic interfaces,” was published in the March 28, 2025, issue of the journal Science. This international collaboration was supported by the National Research Foundation of Korea (Global Research Laboratory Program) and the Ministry of Trade, Industry and Energy (Core Technology Development for Robot Industry Program). ▲ Flexible haptic electronic system for omnidirectional tactile stimulation on skin ▲ Omnidirectional tactile stimulation technology utilizing a stimulation mechanism that takes into account human skin sensory receptors ▲ Auditory stimulation through omnidirectional tactile feedback (top), tactile navigation via object tracking in real-time smart glasses footage (bottom left), and texture reproduction in virtual reality environments (bottom right).
- No. 303
- 2025-04-23
- 1134
