Research

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

Magnetic Control of Lithium Enables a Safe, Explosion-Free ‘Dream Battery’

[POSTECH develops a magnetic-field battery technology that prevents explosions and delivers four times the capacity] A new battery technology has been developed that delivers significantly higher energy storage—enough to alleviate EV range concerns—while lowering the risk of thermal runaway and explosion. A research team at POSTECH has developed a next-generation hybrid anode that uses an external magnetic field to regulate lithium-ion transport, effectively suppressing dendrite*1 growth in high-energy-density electrodes. A POSTECH research team—led by Professor Won Bae Kim of the Department of Chemical Engineering and the Graduate School of Battery Engineering, together with Dr. Song Kyu Kang and integrated Ph.D. student Minho Kim—has introduced a “magneto-conversion*2” strategy that applies an external magnetic field to ferromagnetic manganese ferrite conversion-type*3 anodes. The study has been published in the leading energy journal Energy & Environmental Science. As the electric vehicle and large-scale energy storage markets expand rapidly, the battery industry faces a pressing challenge: developing batteries that store more energy while remaining safe. Lithium metal anodes offer exceptionally high theoretical capacity, but they are prone to forming sharp, needle-like dendrites during repeated charging, which can pierce the separator, cause internal short circuits, and trigger fires or explosions. Meanwhile, conventional graphite anodes—now widely used—have inherent capacity limitations, making next-generation anode technologies essential. The idea was simple: “If a magnet can align iron filings, why not use it to organize the flow of lithium ions?” When lithium is inserted into the manganese ferrite anode, it produces ferromagnetic metallic nanoparticles. Under an applied magnetic field, these nanoparticles align like tiny magnets inside the electrode. This alignment spreads the lithium ions more evenly across the surface, preventing them from concentrating in specific regions. During this process, the Lorentz force*4—the force exerted on charged particles in a magnetic field—further disperses the lithium ions, promoting uniform transport. As a result, instead of forming hazardous dendrites, the anode develops a smooth, dense, and uniform lithium metal deposition layer. In addition, the anode operates as a hybrid system, storing lithium both within the oxide matrix and as metallic lithium deposited on the surface. This dual mechanism enables an energy storage capacity approximately four times higher than that of commercial graphite anodes, while maintaining stable charge–discharge cycling without dendrite formation. Notably, the battery sustained a Coulombic efficiency above 99% for more than 300 cycles, demonstrating excellent long-term stability. Professor Won Bae Kim, who led the research, stated, “This approach simultaneously addresses the two biggest challenges of lithium metal anodes—instability and dendrite formation. It represents a new pathway toward safer and more reliable lithium-metal batteries.” He added, “We expect this technology to serve as a foundation for improving capacity, cycle life, and charging speed in next-generation batteries.” This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (MSIT), , and the Korea Institute for Advancement of Technology (KIAT) grant funded by the Ministry of Trade, Industry and Energy (MOTIE). DOI: https://doi.org/10.1039/D5EE02644J 1) Dendrite: A needle-like, tree-shaped crystalline structure of lithium metal that forms during repeated charging and discharging. If dendrites grow through the electrode surface and penetrate the separator, they can cause internal short circuits and potentially lead to fires or explosions. Suppressing dendrite formation is therefore a central challenge in the development of lithium-metal batteries. 2) Magneto-conversion: A hybrid anode design strategy in which an external magnetic field is applied to ferromagnetic transition-metal oxides used as conversion-type anode materials. This enables magnetic control over lithium-ion flux and nucleation within the electrode, improving uniformity and stability during cycling. 3) Conversion-type: High-capacity anode materials in which metal oxides are converted into metallic nanoparticles and lithium oxide during charging. This conversion reaction allows lithium ions to be stored at capacities significantly higher than those of conventional intercalation-type anodes such as graphite. 4) Lorentz force: The Lorentz force refers to the force experienced by a charged particle as it moves through an electric or magnetic field. In a magnetic field, an ion in motion experiences a force perpendicular to both its direction of travel and the direction of the magnetic field. This effect can be used to redistribute lithium-ion flux more uniformly within the electrode

Aluminum Prevents 'Rapid Aging' in High-Energy Batteries

[The research team of Prof. Kyu-Young Park at POSTECH has revealed the origin of capacity degradation in high-nickel cathodes, and proposed a key strategy for designing next-generation batteries that simultaneously boost energy density and lifespan.] To increase driving range, electric vehicle (EV) batteries rely on high-nickel cathodes. However, this high nickel content has a critical drawback: battery performance degrades rapidly during charging and discharging. The primary cause has now been identified as internal structural distortion, which generates “oxygen holes“ that shorten the battery's lifespan—similar to how a warped pillar can crack a building's walls. A research team from POSTECH (Pohang University of Science and Technology), led by Professor Kyu-Young Park of the Department of Battery Engineering (Graduate Institute of Ferrous & Eco Materials Technology) and the Department of Materials Science and Engineering, has confirmed that this structural distortion creates “double oxygen ligand holes”*1 (simplified as “oxygen holes”), which shortens battery life. Crucially, the team discovered that adding a small amount of aluminum (Al) to the cathode dramatically extends its lifespan by preventing the formation of these holes. The study was published online in the international journal Advanced Functional Materials. There is a growing trend to increase the nickel content in EV batteries to store more energy. However, while more nickel increases energy density, it also causes capacity to fade quickly over repeated charging and discharging cycles. The research team theoretically identified the fundamental mechanism behind this capacity fading: lattice structural distortion, which intrinsically occurs during the charge/discharge process. When the structure distorts, significant oxygen holes form on the oxygen atoms, which destabilizes the lattice oxygen and shortens the battery's lifespan. By substituting a small amount of nickel with aluminum, the team successfully suppressed the formation of these oxygen holes. The aluminum stabilizes the structure by improving the electronic environment around the oxygen atoms. This was confirmed to significantly enhance the battery's lifespan. This research is significant for identifying the cause of degradation in high-nickel cathodes*2 at the atomic level and proposing a strategy to simultaneously improve both energy density and lifespan. It is regarded as a core technology that can enhance both the performance and safety of EV batteries. “This study, which identifies the capacity degradation caused by structural distortion in high-nickel cathodes for EVs, will help expand the design possibilities for next-generation, high-performance batteries,” said Professor Kyu-Young Park, who led the research. He added, “This achievement provides a key strategy that not only improves lifespan but can also mitigate thermal runaway, a critical issue in high-nickel cathodes. We expect it to have a significant impact on the entire rechargeable battery industry.” This research was supported by the Ministry of Trade, Industry and Energy (MOTIE), the Ministry of Science and ICT (MSIT), and the Supercomputing Center of the Korea Institute of Science and Technology Information (KISTI). DOI: https://doi.org/10.1002/adfm.202512501 1) Double oxygen ligand holes: A structural defect created by the removal of two electrons from an oxygen atom, resulting in significant structural instability within the material. 2) High-nickel cathode: A positive electrode material designed with increased nickel content to maximize energy density, though typically limited by a shorter cycle lifespan.

“A Single Molecular Layer” Makes Lithium Batteries Safer and Longer-Lasting

[Researchers at POSTECH, Gyeongsang National University, and KIER develop a molecularly engineered membrane that stabilizes both battery electrodes simultaneously] A team of Korean scientists has developed a breakthrough separator technology that dramatically reduces the explosion risk of lithium batteries while doubling their lifespan. Like an ultra-thin bulletproof vest protecting both sides, this molecularly engineered membrane stabilizes both the anode and cathode in next-generation lithium-metal batteries. The joint research, led by Professor Soojin Park and Dr. Dong-Yeob Han from the Department of Chemistry at POSTECH, together with Professor Tae Kyung Lee of Gyeongsang National University and Dr. Gyujin Song of the Korea Institute of Energy Research (KIER), was recently published in Energy & Environmental Science, one of the world’s leading journals in energy materials. Conventional lithium-ion batteries, which power today’s electric vehicles and energy storage systems, are approaching their theoretical energy limits. In contrast, lithium-metal batteries can store about 1.5 times more energy within the same volume, potentially extending an electric vehicle’s driving range from 400 km to approximately 700 km per charge. However, their practical use has been hindered by serious safety issues. During charging, lithium tends to deposit unevenly on the anode surface, forming sharp, tree-like structures called dendrites. These needle-like growths can pierce the separator between electrodes, causing internal short circuits, fires, and even explosions. To address this, the research team engineered the separator at the molecular level. They chemically grafted fluorine (-F) and oxygen (-O) functional groups onto the surface of a conventional polyolefin separator. These polar groups regulate interfacial reactions between the electrodes and electrolyte, promoting stable and uniform behavior on both sides. As a result, a uniform layer of lithium fluoride (LiF) forms on the anode, suppressing dendrite growth, while harmful hydrofluoric acid (HF) formation is prevented at the cathode side, preserving its structural integrity. This single functional membrane acts as a dual protective layer, simultaneously stabilizing both electrodes within the battery. Under realistic operating conditions, high temperature (55 °C), low electrolyte content, and a thin lithium anode, the newly developed batteries maintained 80% of their initial capacity after 208 charge–discharge cycles. In pouch-type full cells, the technology achieved impressive energy densities of 385.1 Wh kg⁻¹ and 1135.6 Wh L⁻¹, approximately 1.5–1.7 times higher than today’s commercial lithium-ion batteries (250 Wh kg⁻¹, 650 Wh L⁻¹). Professor Soojin Park of POSTECH stated, “This study demonstrates an innovative approach that stabilizes both electrodes of lithium-metal batteries through molecular-level design. It improves lifespan, safety, and energy density while remaining compatible with existing lithium-ion battery manufacturing processes.” Professor Tae Kyung Lee of Gyeongsang National University added, “Using density functional theory (DFT) and molecular dynamics (MD) simulations, we identified how functional groups in the separator influence electronic structures and interfacial reactions at the atomic scale.” Dr. Gyujin Song of KIER commented, “This technology offers high durability and safety suitable for large-scale energy storage systems (ESS) and represents a major step toward the commercialization of eco-friendly, high-energy batteries.” This research was supported by the Ministry of Science and ICT (MSIT) and Ministry of Trade, Industry and Energy of Korea. DOI: https://doi.org/10.1039/D5EE04968G

Drug toxicity predicted by differences between preclinical models and humans

POSTECH Professor Sanguk Kim's team develops a machine learning model to predict drug toxicity based on genotype-phenotype differences between preclinical models and humans In the UK, there was a case where TGN1412, an immunotherapy under development, triggered a cytokine storm within hours of administration to humans, leading to multiple organ failure. Another example, Aptiganel, a stroke drug candidate, was also highly effective in animals but was discontinued in humans due to side effects such as hallucinations and sedation. Even though drugs considered safe in preclinical tests can be fatal in human clinical trials. A machine-learning-based technology has been developed to learn these differences and preemptively identify potentially dangerous drugs before clinical trials. A research team led by Professor Sanguk Kim of the Department of Life Sciences and the Graduate School of Artificial Intelligence at POSTECH, along with Dr. Minhyuk Park and Mr. Woomin Song of the Department of Life Sciences, and Mr. Hyunsoo Ahn of the Graduate School of Artificial Intelligence, has developed a technology that uses machine learning to predict drug side effects in humans. This study was recently published online in the international medical journal eBioMedicine. During the development of new drugs, those that pass preclinical trials often show unexpected toxicity in humans. This issue arises from differences in biological responses between humans and animals. For example, chocolate is generally safe for humans but toxic to dogs. Similarly, a drug that is safe in mice does not necessarily mean it is safe for humans. To date, this "cross-species difference" has been a major reason for failures in new drug development. The research team focused on the "Genotype-Phenotype Difference (GPD)," the biological differences between cells, mice, and humans. They analyzed how genes targeted by drugs function differently in humans and preclinical models, focusing on three key factors: first, the gene's perturbation impact on survival (essentiality); second, the pattern of gene expression in different tissues; and third, the connectivity of genes within biological networks. Validation using data from 434 hazardous drugs and 790 approved drugs revealed that GPD characteristics were significantly associated with drug failure due to toxicity in humans. Predictive power was significantly improved over relying on drug chemical data, with the area under the curve (AUPRC1) increasing from 0.35 to 0.63, and the area under the curve (AUROC2) increasing from 0.50 to 0.75. The developed AI model demonstrated superior predictive performance compared to existing state-of-the-art models. Furthermore, it demonstrated practicality in "chronological validation," which alerts users to drugs facing market withdrawal due to toxicity. After training the prediction model on only drug data up to 1991, it correctly predicted drugs expected to be withdrawn from the market after 1991, achieving 95% accuracy. The significance of this study is that it bridges the "translation gap" between preclinical and clinical trials by quantifying biological differences in cells, preclinical animal models, and humans. Pharmaceutical companies can reduce development costs and time by screening out high-risk candidates before clinical trials, while also improving patient safety. The model's effectiveness is expected to increase as more relevant data and annotations accumulate. Professor Sanguk Kim stated, "This is the first attempt to incorporate differences in genotype-phenotype relationships for drug toxicity prediction. Our framework enables early identification of high-risk drugs in clinical development.” He added, "This approach holds promise for reducing development costs, improving patient safety, and increasing the success rate of therapeutic approvals. Co-first authors Dr. Min-hyuk Park and Mr. Woomin Song stated, "The human-centered toxicity prediction model will be a very practical tool in new drug development. We anticipate that pharmaceutical companies will be able to screen out high-risk drugs in advance at the preclinical stage, thereby improving development efficiency." This research was supported by the National Research Foundation (NRF), funded by the Korean government (MSIT), Medical Device Innovation Center, and the Synthetic Biology Human Resources Development Program. DOI: https://doi.org/10.1016/j.ebiom.2025.105994

“Self-Stacking Lithium” Korean Researchers Eliminate EV Explosion Risks with a New Electrode Design

[POSTECH and Chung-Ang University team have developed a low-tortuosity, lithiophilicity-graded porous structure to suppress dendrite growth in lithium metal batteries] According to the International Council on Clean Transportation, as of early 2024, there are approximately 40 million electric vehicles (EVs) in operation worldwide. Among them, verified battery-related fires in light-duty EVs number just over 500 between 2010 and mid-2023, corresponding to a fire risk of roughly 1 in 100,000 vehicles. While this rate is substantially lower than that for internal-combustion-engine vehicles, EV battery fires remain a major concern because once thermal runaway occurs and a fire ignites, they can be extremely difficult to extinguish and may reignite. A research team from POSTECH (Professor Soojin Park, Dr. Dong-Yeob Han, Ms. Gayoung Lee) and Chung-Ang University (Professor Janghyuk Moon, Mr. Seongsoo Park) has developed a novel three-dimensional porous structure that significantly improves both the lifespan and safety of lithium-metal batteries (LMBs). Their work was published in Advanced Materials. Lithium metal batteries promise much higher energy density than today’s lithium-ion batteries and could dramatically extend EV driving range. However, the main barrier to commercialization has been the tendency of lithium metal to deposit unevenly during charging and discharging, forming needle-like “dendrites” that can pierce separators and cause internal short-circuits or even explosions. The team’s solution is simple yet effective: they engineered a porous host structure with straight, low-tortuosity channels and a built-in lithiophilicity gradient enabling uniform lithium deposition from the bottom up. Think of a parking garage: if the entrance is narrow and lanes are winding, cars tend to bunch at the entrance. But if you build wide straight ramps and make lower floors more spacious, vehicles naturally fill the lower floors first. Their electrode design applies this principle to lithium ions in the battery. Using a nonsolvent-induced phase separation (NIPS) process, they created the porous host by mixing a polymer matrix with carbon nanotubes (CNTs) and silver (Ag) nanoparticles to enhance electrical conductivity, while introducing an Ag layer on a copper substrate to induce lithium nucleation at the base. As a result, bottom-up lithium deposition with fully suppressed dendrite growth and greatly improved structural stability. In tests, batteries built with this host achieved an energy density of 398.1 Wh/kg and 1,516.8 Wh/L, far exceeding typical lithium-ion batteries (~250 Wh/kg, ~650 Wh/L). Even under commercial-level conditions with low electrolyte content, a thin lithium anode, and real-world cathodes such as NCM811 and LFP, they demonstrated outstanding stability without short circuits or capacity collapse. If applied to EVs, this improvement could potentially extend driving range by roughly 60–70% (for example, a vehicle that currently travels ~400 km per charge might reach ~650–700 km). Professor Park stated, “This research presents a new way to simultaneously control ion transport pathways and lithium growth behaviour inside electrodes, without relying on complex manufacturing processes. Designing both the ‘path’ and the ‘direction’ of lithium movement will be a turning point in advancing toward the commercialization of safe, high-energy lithium-metal batteries.” Professor Moon added, “Our process allows simultaneous control of microstructure and chemical gradients through a simple fabrication route, making it highly scalable for industrial production.” This research was supported by the Ministry of Science and ICT (Republic of Korea). DOI: https://doi.org/10.1002/adma.202510919

Concentration‑Controlled Doping Turns a p‑Type Polymer into Its n‑Type Counterpart

[POSTECH-SKKU Joint research team Discovers the Molecular Mechanism Behind Polarity Switching in Conjugated Polymer Semiconductors] A South Korean research team has, for the first time, uncovered the molecular-level mechanism by which trace amounts of impurities—known as dopants—can reverse charge polarity in organic polymer semiconductors. A joint research team led by Professor Kilwon Cho, PhD candidates Eunsol Ok and Sein Chung from the Department of Chemical Engineering at POSTECH, and Professor Boseok Kang from the Department of Nano Engineering at Sungkyunkwan University (SKKU), has revealed at the molecular level how adjusting the concentration of a single dopant enables polymer semiconductors*1 to switch between positive (p-type) and negative (n-type) conduction*2. Their findings were recently published in the highly-ranked materials science journal, Advanced Materials. Semiconductors are core materials that regulate current flow in modern electronic devices. While traditional silicon-based semiconductors offer excellent performance, their rigidity limits their use in emerging applications such as stretchable displays, wearable electronics, and electronic skin. In contrast, organic polymer semiconductors are lightweight and mechanically flexible, making them promising candidates for next-generation electronics. However, a major challenge has been the limited availability of stable n-type organic semiconductors. Most conjugated polymers naturally exhibit p-type behavior, while existing n-type counterparts often suffer from poor ambient stability. To enable practical applications, a strategy is needed that allows both p-type and n-type functionalities within a single polymer system. The research team addressed this issue through a phenomenon known as polarity switching. When a typically p-type polymer is doped with a sufficiently high concentration of a p-type dopant such as gold(III) chloride (AuCl₃), the dominant charge carriers shift from holes to electrons. This concentration-dependent polarity reversal allows a single polymer to exhibit both p-type and n-type characteristics—eliminating the need for separate materials or complex multilayer device architectures. To uncover the underlying mechanism, the team analyzed polymer films doped with AuCl3. They found that the oxidation states of gold and chloride ions evolve during doping, leading to a substitutional chlorination reaction with the polymer chains. This chemical reaction induces structural reordering of the polymer backbone, realigning the molecular structure and reorganizing charge transport pathways, ultimately driving the polarity switching. Based on this mechanism, the researchers fabricated a p–n organic homojunction diode using a single polymer doped at two different concentrations. The device exhibited a rectification ratio tens of thousands of times greater than conventional single-material organic diodes, highlighting its potential for high-performance, flexible electronic devices with simplified architectures. Professor Kilwon Cho and Boseok Kang explained, “Our study is the first to identify the precise chemical and structural mechanism behind polarity switching in polymer semiconductors. This discovery paves the way to precisely control the electrical properties of organic semiconductors, making future electronic devices simpler, more stable, and more efficient.” The research was supported by the National Research Foundation of Korea (NRF) and the Ministry of Science and ICT through several national programs, including the Basic Research Program, Nano & Material Technology Development, Future Technology Laboratories, and the National Core Materials Research Group. DOI: 10.1002/adma.202505945 1) Polymer Semiconductor: A type of plastic-like material with semiconducting properties. These materials are used in organic electronic devices such as OLEDs, wearable sensors, and energy storage systems. 2) p-type and n-type Semiconductors: Semiconductor classifications based on charge carrier type—p-type conducts through positive "holes," while n-type conducts via negative electrons. Both are essential to forming circuits in electronic devices.

Conquering Intractable Blindness with an Artificial Retina

[A joint research team from POSTECH, Eunpyeong St. Mary’s Hospital, and Hankuk University of Foreign Studies has developed a 3D-bioprinted retina-on-a-chip and retinal vein occlusion model. ] Retinal vein occlusion (RVO)*1 is one of the leading causes of vision loss worldwide, often triggered by chronic diseases such as hypertension and diabetes. Similar to a blocked water pipe causing backflow and pressure buildup, an occluded retinal vein leads to edema, inflammation, and neovascularization, ultimately resulting in irreversible blindness. Despite the availability of anti-VEGF injections and laser therapy, there is still no effective treatment that fully restores damaged retinal tissues, primarily due to the lack of physiologically relevant disease models. A joint research team led by Professor Dong-Woo Cho of the Department of Mechanical Engineering at POSTECH, Professor Jae Yon Won of the Department of Ophthalmology and Visual Science at Eunpyeong St. Mary’s Hospital, and Professor Joeng Ju Kim of the Department of Bioscience and Biotechnology at Hankuk University of Foreign Studies (HUFS) has successfully developed an RVO disease model based on a 3D-bioprinted retina-on-a-chip platform that closely recapitulates the pathological microenvironment of retinal vein occlusion. This breakthrough study was published in Advanced Composites and Hybrid Materials, a top-tier international journal in materials and nanoengineering. The team utilized an integrated 3D bioprinting system combined with a hybrid retinal decellularized extracellular matrix (RdECM*2) bioink*3 to fabricate a retina-on-a-chip featuring both vascular and neural layers. By fabricating vascular occlusion within the chip, the model successfully reproduced hallmark RVO pathologies—such as inflammation, barrier dysfunction, and aberrant angiogenesis—allowing real-time observation of cellular interactions between endothelial and retinal cells. The RVO model exhibited vascular leakage and edema responses comparable to those observed in clinical RVO patients. Furthermore, in the RVO model, the researchers observed that the vascular endothelium lost its selective permeability, mirroring the pathological changes seen in actual patients. When conventional anti-inflammatory or anti-angiogenic drugs were administered, the model exhibited drug responses highly consistent with those observed in clinical RVO cases. Specifically, aspirin effectively suppressed vascular damage, while treatment with dexamethasone*4 and bevacizumab*5 reduced inflammation and abnormal neovascularization. These findings demonstrate that the developed platform can accurately reproduce pharmacological reactions in vitro, validating its potential as a preclinical drug evaluation and patient-specific therapeutic screening system. The team envisions that this RVO model will serve as a powerful preclinical platform for investigating RVO pathogenesis, evaluating novel therapeutics, and reducing reliance on animal experiments. The approach also demonstrates the potential of organ-specific dECM (Decellularized Extracellular Matrix) bioinks to reproduce complex human tissue microenvironments for personalized medicine. This research was supported by the Alchemist Project of the Ministry of Trade, Industry and Energy, the National Program for Regenerative Medicine, the Young Researcher Program of the National Research Foundation of Korea, and the Research Fund of Hankuk University of Foreign Studies. DOI: https://doi.org/10.1007/s42114-025-01455-2 1. Retinal Vein Occlusion (RVO): A vascular disorder caused by the blockage of retinal veins, leading to hemorrhage and swelling that can result in severe vision loss. 2. RdECM (Retinal Decellularized Extracellular Matrix): A naturally derived biomaterial retaining tissue-specific biochemical cues for retinal tissue regeneration. 3. Bioink: A biomaterial formulation used in 3D bioprinting to fabricate living tissue structures. 4. Dexamethasone: a corticosteroid drug frequently used in clinical settings to reduce inflammation and edema in patients with retinal vein occlusion. 5. Bevacizumab: an anti-VEGF antibody commonly used in the clinical treatment of retinal vascular diseases.

Tagging ‘Fake Targets’ for Antigen-independent Immunotherapy

[POSTECH-UCLA Collaborative Team Develops Novel ‘Univody’ Platform for Antigen-Independent Cancer Immunotherapy] A research team led by Professor Won Jong Kim from the Department of Chemistry and POSTECH-Catholic biomedical engineering institute at POSTECH, along with Ph.D. candidate Seonwoo Kang, has collaborated with Dr. Junseok Lee’s team at UCLA to introduce a groundbreaking cancer immunotherapy strategy. This approach involves attaching “fake targets” to tumor cells to guide immune cell attacks, overcoming the limitations of conventional antibody-based therapies. The study, drawing significant attention in the fields of nanomedicine and biomaterials, has been published online in the prestigious journal ACS Nano. One of the major challenges in cancer treatment is the ability of tumors to evade immune surveillance. Traditional antibody therapies rely on the recognition of specific antigens expressed on the tumor cell surface. However, antigen expression is often low or heterogeneous in real tumors. Some tumors even lack the specific antigen—so-called “antigen-negative tumors”—greatly limiting the therapeutic efficacy. To address this, the research team developed a novel “Universal Antibody” (Univody) technology, enabling immune cells to attack tumors regardless of antigen presence. By genetically engineering a construct that allows the stable expression of antibody Fc*1 fragments on the tumor surface, the researchers effectively marked tumor cells for immune recognition. A specialized delivery system, termed LPP-PBA*2 (Lipopolyplex modified with Phenylboronic Acid), was designed to selectively deliver this genetic material. PBA moieties on the surface of LPPs specifically interact with overexpressed sialic acid residues on cancer cells, ensuring tumor-specific delivery and expression of the antibody fragments. The engineered tumor cells expressing Fc fragments became immediate targets for immune attack. Experimental results confirmed that NK*3 (natural killer) cells recognized the Fc-tagged tumor cells, launched cytotoxic responses, and triggered broader immune activation. In animal models of triple-negative breast cancer and melanoma, the Univody system significantly suppressed tumor growth. Unlike conventional antibody therapies, the Univody platform does not rely on tumor-specific antigens, offering a universal and flexible immunotherapeutic approach. “Because it functions independently of antigen type, this platform holds promise for broad application across various cancers,” said Professor Kim. Dr. Junseok Lee from UCLA emphasized the innovation of the strategy, stating, “Directly tagging antibody fragments onto tumor cells represents a transformative approach that can overcome key limitations in current cancer immunotherapies.” This study was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT, through the Leader Researcher Program and IRC Project, as well as by the ITECH R&D Program of the Ministry of Trade, Industry and Resources (MOTIR) and Korea Evaluation Institute of Industrial Technology (KEIT). DOI: https://pubs.acs.org/doi/10.1021/acsnano.5c08128 1. Fc (Fragment crystallizable): The stem region of an antibody that allows immune cells to recognize and bind to the antibody. 2. LPP-PBA (Phenylboronic acid-modified Lipopolyplex): A gene delivery carrier composed of a liposome (lipid bilayer) and PEI (a cationic polymer). It is functionalized with phenylboronic acid (PBA) on its surface, which enables selective binding to sialic acid—overexpressed on cancer cells—allowing preferential targeting of tumor cells over normal cells. 3. NK Cell (Natural Killer cell): A type of innate immune cell capable of directly attacking virus-infected or cancerous cells without prior sensitization.