Researchers Find New Way to Rebuild Organic Semiconductor Backbones

Abstract Iterative syntheses—repeating sequences of the same reactions to construct complex molecules—can facilitate the synthesis of specific classes of small molecules with structural redundancies, including acenes. Despite the prevalence of zigzag edges in the structures of acenes, few examples that effectively manipulate the edge configurations of acenes exist. In this study, the rationally designed iterative synthesis of three pentacene derivatives with continuous boron–oxygen bonds at the zigzag edges is reported. The simple and efficient two-step iteration employed ipso iodination with a trimethylsilyl group as the directing group and Suzuki cross-coupling/condensation reactions. Because of the fundamental role of pentacene derivatives in a broad spectrum of electronic applications, these findings are valuable across a diverse range of chemical and physical disciplines. Researchers at UNIST have introduced a new, efficient way to alter the backbone of organic semiconductors, giving researchers finer control over the molecules used in flexible displays, sensors, solar cells, and other electronic devices. Led by Professors Young S. Park and Seung Kyu Min from the Department of Chemistry, the team created an iterative synthesis method that places boron–oxygen bonds along the edge of pentacene, a well-known organic semiconductor made of five fused benzene rings. Organic semiconductors are valued because they are light, flexible, and chemically tunable. Small changes in a molecule's length, shape, or atomic makeup can shift how it absorbs light, emits light, or transports charge. But chemists have usually tuned these materials by attaching groups to the outside of the molecule. Changing the carbon framework itself has remained much harder. The new method works inside that framework. It inserts oxygen and boron atoms into the pentacene backbone, reshaping the molecule rather than simply decorating its edges. Dr. Sunghwa Jung, the study's first author, said the process relies on a repeated two-step cycle. “Each cycle begins with iodination at a specific site, followed by ring closure using a boron reagent,” he said. “By repeating the sequence, we can build pentacene structures with consecutive boron–oxygen bonds along the molecular edge.” By carefully controlling these cycles, the team synthesized three different pentacene derivatives, each with distinct boron–oxygen arrangements. The molecules absorbed and emitted light at different wavelengths, showing that their optical properties could be tuned through structure. All three also showed fluorescence quantum yields above 0.70, a sign of efficient light emission. The results point to possible uses in light-emitting organic semiconductors, fluorescent sensors, and optoelectronic materials that require bright, efficient emission. “This work gives us a stepwise way to build new acene molecules with consecutive boron–oxygen bonds,” Professor Park said. “Because the process can control both molecular length and arrangement, it expands the structures available for organic semiconductor design.” The study was published online in Angewandte Chemie International Edition on April 16, 2026. It was supported by funding from the National Research Foundation of Korea (NRF) and the Ministry of Trade, Industry and Energy (MOTIE). Journal Reference Seonghwa Jeong, Si-In Kim, Jonghwan Lee, et al., “Iterative Synthesis of Pentacene Derivatives with Continuous Boron–Oxygen Bonds,” Angew. Chem. Int. Ed. , (2026).

2026.05.22

Innovative Nanoscale Design Produces Stronger Signals When Bent

Abstract Second-harmonic generation (SHG) in monolayer transition-metal dichalcogenides is highly sensitive to mechanical strain, often leading to signal suppression under deformation. Here, we demonstrate reconfigurable SHG in monolayer MoS2 integrated with plasmonic nanoslits, where localized plasmonic fields counteract strain-induced suppression. The plasmonic nanoslits induce strong spatially localized field enhancement, yielding an SHG enhancement of up to 8000, estimated by normalizing the signal to the illumination area, relative to MoS2 on unpatterned Au films. Applying 1.2% compressive strain increases the SHG intensity by approximately threefold relative to the unstrained state, demonstrating effective strain-enabled modulation. Upon mechanical bending, the SHG response is reversibly modulated and remains stable after an initial preconditioning regime, retaining more than 95% of its initial intensity over repeated bending cycles. This strain-adaptive platform demonstrates robust cycling stability and provides a previously unexplored strategy for dynamically reconfigurable nonlinear metasurfaces, enabling applications in wearable sensors, tunable modulators, and compact frequency converters. A collaborative team from UNIST and Ajou University has unveiled a flexible optical device that generates a stronger light signal when bent. This achievement defies the traditional understanding that mechanical deformation diminishes optical performance, paving the way for advanced wearable sensors and flexible photonic systems. Led by Professors Hyeong-Ryeol Park and Seon Namgung of UNIST Department of Physics, alongside Professor Young-Hwan Ahn at Ajou University, the team engineered a device capable of converting incident light into a shorter wavelength. Unlike conventional devices that depend on bulky, thick materials, this ultra-thin structure employs molybdenum disulfide (MoS2), a two-dimensional semiconductor only a few atoms thick. While bending MoS2 typically weakens its optical signals, the researchers redesigned the architecture to focus electromagnetic energy within nanoscale gaps—merely 20 nanometers wide—that concentrate fields during compression. When bent inward, these gaps are narrow, amplifying the emitted light. On the other hand, when relaxed, they widen, diminishing the signal. This dynamic modulation renders the device both strain-sensitive and capable of real-time optical control. Experimental results demonstrated that compressing the device by approximately 1.2% increased its second-harmonic output—converting 800 nm light to 400 nm—by nearly threefold. Within these nanoscale gaps, the local electromagnetic field exceeds 8,000 times that of a flat MoS₂ film on gold. Notably, the device maintained over 95% of its initial performance even after 190 bending cycles, with minimal material degradation. “This nanoscale design not only enhances the optical signal but also provides inherent protection for the material,” said lead researcher Sobhagyam Sharma from UNIST. “It offers a straightforward approach to developing flexible sensors that respond to mechanical stress through changes in light emission.” Professor Park added, “This innovation lays the groundwork for deformation sensors that operate via optical signals and offers new insights into strain effects on two-dimensional materials.” The findings were published in Science Advances on May 8, supported by the National Research Foundation of Korea (NRF), the Institute for Information & Communications Technology Planning & Evaluation (IITP), and UNIST. Journal Reference Sobhagyam Sharma, Satyabrat Behera, Byung Hee Son, et al ., “Reconfigurable second-harmonic generation via plasmonic nanoslits counteracting strain-induced suppression in monolayer MoS2,” Sci. Adv., (2026).

2026.05.22

Scientists Discover a New Way to Make Drug-Resistant Cancer Treatable Again

Cancer cells survive by repairing damage to their DNA—even damage that would normally be fatal. One of their most important defense systems is homologous recombination, a high-precision repair pathway that fixes broken DNA using key proteins such as RAD51 and CHK1. While therapies such as PARP inhibitors have successfully targeted this vulnerability, many tumors eventually regain their DNA repair ability and become resistant to treatment. A research team, led by Distinguished Professor Kyungjae Myung of the Department of Biomedical Engineering and Director of the Center for Genomic Integrity (CGI) within the Institute for Basic Science (IBS) at UNIST, in collaboration with Joo-Yong Lee from Chungnam National University, has now uncovered a new strategy to overcome this resistance. Their findings show that cancer cells can be made vulnerable again—not by altering genetic mutations, but by destabilizing the DNA repair machinery itself. In cells, DNA repair proteins are not static. Their levels are tightly regulated to maintain a balance between repair and genome stability. However, the researchers found that this balance can be deliberately disrupted. Through a cell-based screening approach designed to identify modulators of replication stress responses, the team discovered a small molecule, called UNI418. When applied to cancer cells, UNI418 caused a significant reduction in key DNA repair proteins, including RAD51 and CHK1. As these proteins were depleted, the cells lost their ability to efficiently repair DNA damage. To understand how this happens, the researchers examined how these proteins are controlled. They found that UNI418 activates a protein degradation system known as the Cul4A ubiquitin ligase complex, which tags specific proteins for destruction. This effectively dismantles the DNA repair system from within. Co-corresponding author Professor Joo-Yong Lee stated, "We identified a mechanism in which key DNA repair proteins are actively degraded inside the cell. This provides a new way to regulate homologous recombination beyond genetic mutations." The team further traced how this degradation pathway is triggered. UNI418 disrupts a signaling pathway involved in inositol phosphate metabolism, reducing the levels of a molecule called IP6. Under normal conditions, IP6 suppresses Cul4A activity. When IP6 levels drop, this suppression is lifted, allowing the degradation system to become active. As a result, Cul4A—together with its adapter protein WDR5—targets DNA repair proteins such as RAD51 for degradation, effectively shutting down homologous recombination. Functionally, this creates a state similar to DNA repair deficiency, even in cancer cells that had previously restored their repair capacity. This finding is particularly important for overcoming resistance to PARP inhibitors, one of the major challenges in current cancer therapy. The researchers tested whether this approach could improve treatment outcomes. In multiple cell-based experiments, UNI418 significantly increased the sensitivity of cancer cells to PARP inhibitors. Notably, it was also effective in PARP inhibitor-resistant cancer cells, restoring their responsiveness to treatment. Co-corresponding author Director Myung added, “By weakening the DNA repair system, we can re-sensitize tumors that have become resistant to existing therapies. This suggests a new strategy for expanding the effectiveness of PARP inhibitors.” The team further validated these findings in animal models. In tumor xenograft experiments, UNI418 suppressed tumor growth, particularly when combined with the PARP inhibitor Olaparib. Importantly, this effect was observed even in models that mimic treatment-resistant cancers. These results indicate that cancer cells remain dependent on DNA repair systems even after developing resistance—and that disrupting protein stability can expose this vulnerability. Beyond its therapeutic implications, the study also reveals a new biological connection between cellular metabolism and DNA repair. By linking IP6 signaling to the Cul4A-mediated protein degradation pathway, the work uncovers a previously unrecognized mechanism regulating genome stability. Co-corresponding author Director Myung remarked, "This study demonstrates that controlling the stability of DNA repair proteins can directly impact cancer cell survival. It also highlights a new therapeutic direction for overcoming drug resistance." Ultimately, the findings suggest that drug-resistant cancers can be made vulnerable again—not by changing their genes, but by dismantling the systems they rely on to repair DNA. Although UNI418 itself will require further development, the mechanism identified in this study provides a promising foundation for next-generation combination therapies. The findings of this research have been published in Nature Communications on April 4, 2026. Kyungjae Myung Distinguished Professor, Department of Biomedical Engineering, UNIST Director, IBS Center for Genomic Integrity (CGI) E: kmyung@ibs.re.kr William I. Suh IBS Public Relations Team E: willisuh@ibs.re.kr Story Source Materials provided by the Institute of Basic Science . Journal Reference Seon-gyeong Lee, Yuri Seo, Seula Jeong, et al., "Targeting IP6 signaling to destabilize homologous recombination proteins to overcome PARP inhibitor resistance," Nat. Commun., (2026). DOI: 10.1038/s41467-026-71421-z

2026.05.21

New Study Uncovers Current-Driven Spin Polarization in Chiral Nanowires

Abstract The spin dynamics of electrons in chiral molecular systems remains a topic of intense interest, particularly regarding whether geometric chirality inherently induces spin polarization in current-carrying electrons. In this work, we employ ab initio real-time time-dependent density functional theory (rt-TDDFT) to directly simulate the interplay among charge current, spin, and orbital. This real-time tracking extends beyond perturbative treatments, and we analyze how nonequilibrium currents effectively lift the symmetry constraints of screw rotation and time-reversal symmetry. We find that the emergence of spin and orbital angular momenta is dynamically correlated with a concomitant loss of translational (linear) momentum, which we interpret as an intrinsic consequence of current-driven symmetry lowering. The implications of this mechanism for chirality-induced spin selectivity and spintronics device design are discussed. A new theoretical study shows that simply passing an electric current through chiral, helical materials can generate the intrinsic spin of electrons. Using real-time quantum calculations, researchers tracked how electron motion transforms into spin and orbital angular momentum. Led by Professor Noejung Park from the Department of Physics at UNIST, the team partnered with scientists from the University of Missouri, Pennsylvania State University, and the Max Planck Institute. They simulated electrons flowing through a one-dimensional helical conductor—specifically selenium nanowires—and uncovered the microscopic process behind spin polarization. Electrons carry two types of angular momentum: spin and orbital. Under normal conditions, these cancel out. But in chiral structures, an electric current favors electrons with a specific spin, creating a phenomenon known as chirality-induced spin selectivity (CISS). This effect enables spin control without magnetic fields, promising for spintronic devices. Yet, how current drives this spin polarization remained unclear. The simulations revealed that as electrons move along the helix, their linear momentum converts into orbital angular momentum. This transfer, driven by the current, couples with the electron’s spin via quantum spin-orbit interaction, leading to a net spin polarization. Notably, this process activates only above a certain current threshold and persists even after the electric field is turned off. Professor Park explains, “Our work shows that the flow of current itself creates and sustains spin polarization in chiral conductors. It highlights a fundamental mechanism—orbital angular momentum transfer—that can be harnessed for next-generation spintronic devices operating purely on electrical signals.” The findings were published in ACS Nano on April 23, 2026. The study has been supported by the National Research Foundation of Korea (NRF) grants funded by the Ministry of Science and ICT (MSIT), and by a KIAT grant funded by the Ministry of Trade, Industry, and Energy (MOTIE). Journal Reference Uiseok Jeong, Daniel Hill, Esmaeil Taghizadeh Sisakht, et al., "Current-Driven Symmetry Breaking and Spin–Orbit Polarization in Chiral Wires," ACS Nano, (2026).

2026.05.21

New Radical Relay Strategy Enables One-Step Multi-Component Molecular Assembly

Abstract The formation of multiple and remote C–C bonds remains highly challenging owing to difficulties in reactivity and selectivity control. Herein, we report a nickel-catalyzed twofold conjunctive cross-electrophile coupling that employs an alkene and a 1,3-enyne as conjunctive platforms and alkyl and aryl halides as coupling partners. Through a philicity-alternating radical relay followed by selective radical capture, the reaction enables the formation of three or more C–C bonds. Combined experimental and theoretical investigations provide a rationale for the sequential radical additions to the π systems and the selective capture of a radical intermediate by the nickel catalyst. Furthermore, a five-component coupling showcases the sequential and controlled addition of alkyl and aryl moieties across three conjunctive units, demonstrating the synthetic versatility of the twofold conjunctive coupling. A joint research team from UNIST and DGIST has developed a new chemical synthesis method that links four different compounds together in a single reaction step, offering a faster and more controllable route to building complex molecules vital for pharmaceuticals and advanced materials. The study, led by Professors Sung You Hong and Jan-Uwe Rohde from the Department of Chemistry, in collaboration with Professors Sangwon Seo and Byunghyuck Jung from DGIST, introduces the first nickel-catalyzed twofold conjunctive cross-electrophile coupling system capable of connecting four distinct chemical building blocks through one controlled reaction sequence. Modern chemical synthesis typically excels at connecting two or three molecular components at a time. Extending those reactions to four or more components has remained difficult because reactive intermediates tend to generate unwanted byproducts or trigger uncontrolled polymerization. The research team addressed this challenge through a carefully engineered radical relay mechanism. In the reaction, highly reactive radical intermediates alternately shift between electrophilic and nucleophilic states, guiding molecules to connect in a precise order and at defined positions. The process functions much like a relay race, with each reaction intermediate triggering the next step in sequence. Nickel catalysts play a central role by generating the initial radical species and selectively capturing intermediates at the final stage, preventing side reactions and maintaining control throughout the synthesis. The method enables sequential coupling among alkyl halides, alkenes, 1,3-enynes, and aryl halides to form multiple carbon-carbon bonds in a single operation. Under modified reaction conditions, the system can even be extended to five-component coupling reactions. The study was co-authored by Ji Hwan Jeon and Da Hye Kim of UNIST as first authors. Beyond the technical advance itself, the researchers say the work opens a new middle ground between traditional small-molecule synthesis used in pharmaceuticals and polymer synthesis used in plastics and materials manufacturing. “This study presents a new strategy for connecting multiple molecular components sequentially within a single reaction system,” the research team explained. “It offers a conceptual bridge between precision organic synthesis and macromolecular chemistry.” Professor Hong said the approach could become a foundational technology for designing complex organic molecules and next-generation functional materials. “The method provides a versatile platform for constructing sophisticated molecular architectures with greater efficiency and control,” he said. The findings of this research were published in Advanced Science on April 9, 2026. The study has been supported by the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF) through the ERC program (Engineering Research Center for Microplastic through Bio/Chemical engineering Convergence Process). Journal Reference Ji Hwan Jeon, Da Hye Kim, Gun Ha Kim, et al ., “Nickel-Catalyzed Twofold Conjunctive Coupling via Philicity-Alternating Radical Relay,” (2026).

2026.05.20

Ultra-Sensitive Wearable MXene Sensor for Real-Time Human-Machine Interfaces

Abstract In the era of autonomous systems and multifunctional devices, sensors serve as vital sensory components in our Internet of Things and technologically advanced society. At the end of the synthetic 2D nanomaterials research, MXenes are not just chemicals but materials, depending on how they are synthesized for targeted applications, such as dual-functional temperature and pressure-sensitive wearable sensing. The current findings introduce the potential strategic role of nitrogen atoms to the Ti-Carbonitride (Ti3CNTz) structure in a controlled compositional stoichiometry of Ti3C1.8N0.2Tz, Ti3C1.5N0.5Tz, Ti3CNTz, Ti3C2Tx to deliver an ultrahigh sensitivity (300%–400% temperature & pressure sensitivity enhancement) and durability in real-time human-machine sensing interface applications. These recorded outstanding dual-sensing performance outplays many other MXene stoichiometries, graphene-related 2D nanomaterials, and their associated composites. Synchrotron radiation-based We provide valuable insights for developing advanced sensing materials, emphasizing the need to investigate the fundamental mechanisms that control the interactions among layered 2D MXene materials and the sensing device functions that bridge human and machine interfaces. A research team, affiliated with UNIST, has unveiled a groundbreaking wearable sensor material, capable of detecting body temperature, coughing, swallowing, and other subtle physiological signals when applied to the skin. Led by Professors Soo-Hyun Kim and Soon-Yong Kwon from the Graduate School of Semiconductor Materials and Devices Engineering, the team developed a novel titanium carbonitride-based MXene (Ti3CNTz) with unparalleled sensitivity to both temperature and pressure. This innovation achieves over three times the temperature sensitivity and more than four times the pressure sensitivity of conventional MXenes, enabling precise detection of minute biological cues. This advanced material, Ti3CNTz, benefits from carefully optimized nitrogen content, which enhances electrical conductivity and lattice vibrational responses. Its unique structure not only boosts sensitivity but also enhances mechanical durability, as validated through both theoretical and experimental analysis. In practical applications, sensors made from this MXene accurately distinguish subtle vocal cord vibrations, blinking, pulse waves, and gait patterns—all without direct contact. Remarkably, they can even detect temperature changes from a short distance, such as infrared heat emitted by a smartphone flash. Professor Kim highlights that this multifunctional sensor represents a transformative development in next-generation human-machine interfaces and electronic skin. Its versatility paves the way for numerous applications in healthcare, energy storage, catalysis, and electromagnetic shielding. Professor Debananda Mohapatra, the first author of the study, emphasized that this 2D MXene advancement sets a new benchmark in intelligent sensing, enabling next-generation sensing devices to bridge human–machine interfaces with exceptional sensitivity and scalability. Also said, this work serves as a stepping stone for the vast 2D MXene family of nanomaterials, accelerating applications across healthcare, AI robotics, and smart wearables. Published in Advanced Functional Materials , this research was supported by the National Research Foundation of Korea (NRF) and the InnoCORE program of the Ministry of Science and ICT. Journal Reference Debananda Mohapatra, Ju-Hyoung Han, Hyun Jin Kang, et al ., “Anomalous Pressure-Temperature Ultrahigh Sensitivities in Atomically Engineered Carbonitride MXenes for Multifunctional Wearable Human–Machine Interfaces: Joint Computational–Experimental Elucidations,” Adv. Funct. Mater., (2026).

2026.05.18