https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/250 2026-07-24T19:48:44Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212739 Title: Low-frequency ionic-electronic coupling for energy-efficient noise-resilient wireless bioelectronics Authors: Kim, Ji Hong; Kim, Haerim; Rhee, Jaewon; Kim, Joo Sung; Choi, Hanbin; Choi, Won Hyuk; Park, Yoseph; Kim, Jong Hwi; Kim, So Young; Ahn, Seungyoung; Kim, Do Hwan Abstract: Wireless bioelectronics demand transduction strategies that are simultaneously sensitive, noise-resilient, and biologically safe. Conventional wireless sensors typically rely on dielectric capacitors with inherently low capacitance, necessitating operation at MHz frequencies. Such high-frequency coupling often introduces electromagnetic interference, tissue heating, and degraded signal fidelity in biological environments. Here we present a wireless low-frequency electrochemical sensing (WiLECS) platform that couples ionic dynamics with low-frequency LC resonant circuits. The device combines a biocompatible ion gel, composed of a choline-malate ionic liquid embedded in a chitosan matrix with functionalized Au nanoparticles, with a miniaturized LC antenna. Unlike conventional capacitive sensors, WiLECS employs piezo-driven ion redistribution to modulate the dielectric environment of the circuit, enabling sustainable wireless transduction below 1 MHz with high sensitivity and reliability. This approach directly bridges ionic dynamics and electronic resonance, allowing mechanical stimuli to be transduced into biologically safe low-frequency electronic signals. As proof of concept, we demonstrate real-time wireless blood-pressure monitoring in artificial arteries with atherosclerotic plaque, showing resolution of subtle pressure variations under clinically relevant conditions. 2026-12-01T00:00:00Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/217616 Title: A dual-function chromium-trapping current collector enabling poisoning-free and durable high-temperature fuel cells Authors: Park, Sun-Young; Jo, Kanghee; Hwang, Seongyeon; Kang, HeeChan; Park, Mi Young; Kim, Hyo-Jin; Park, Jinhong; Lee, Insung; Ko, Min Jae; Kim, Jun Hyuk; Kim, Kyeounghak; Kim, Jae Jin; Yoon, Kyung Joong Abstract: High-temperature degradation remains a critical barrier to solid oxide fuel cell (SOFC) commercialization, with Cr vapor–induced electrode poisoning representing one of the most persistent challenges. Here, we present a Co–Ni spinel oxide as a dual-function current collector that actively scavenges Cr vapor while maintaining efficient electrical coupling between the cell and interconnects. Upon Cr exposure, the spinel incorporates Cr via preferential substitution at octahedral Co sites, assisted by Ni acting as a redox-flexible mediator, thereby enabling effective Cr interception without compromising electrical conductivity. Foam- and porous-layer-type Cr-trapping current collectors were developed for practical implementation in realistic SOFC systems. Under severe Cr exposure, reference cells exhibited a 17.6% performance loss over 200 h, whereas cells incorporating the Cr-trapping collector showed complete suppression of degradation, demonstrating robust and sustained electrode protection. This strategy provides a simple, scalable, and effective route to enhancing SOFC durability and extending system lifetime. 2026-10-01T00:00:00Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/218686 Title: Hydrogen supplementation improves glucose-based n-caproate production in Caproiciproducens galactitolivorans with reverse β-oxidation-associated redox remodeling Authors: Nair, Pranav Sasidharan; Kim, Hyunjin; Kang, Seongcheol; Jeon, Byoung Seung; Angenent, Largus T.; Sang, Byoung-In Abstract: Medium-chain carboxylic acids, such as n-caproate, are attractive sustainable platform chemicals. However, their microbial production is often limited by electron availability and low product selectivity. This study investigated the effect of hydrogen supplementation on glucose-based n-caproate production by Caproiciproducens galactitolivorans. Batch fermentation was performed under various hydrogen pressures (0 to 600 kPa). At 600 kPa hydrogen, n-caproate reached 8.0 g L−1, accompanied by a 66% increase in n-caproate selectivity and a tenfold increase in the intracellular redox-cofactor ratio, consistent with enhanced redox-cofactor turnover. Multi-omics analysis indicated metabolic remodeling under hydrogen-enriched conditions, including the increased abundance of key enzymes in the reverse β-oxidation pathway and redox-associated functions. In contrast, although fatty acid biosynthesis genes were transcriptionally induced, this transcriptional increase was not reflected at the protein level, suggesting a metabolic response more consistent with reverse β-oxidation-supported n-caproate synthesis than with fatty acid biosynthesis. These results support the use of hydrogen as a clean external reducing agent for improving n-caproate yield and redox efficiency in defined microbial systems. This study provides mechanistic insights into redox-driven metabolic control and selective n-caproate production in a defined microbial chain elongation system. 2026-10-01T00:00:00Z https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/212783 Title: Highly sensitive electrospun ammonia sensor using polydiacetylene incorporating hemi-protonated cytosine Authors: Park, Sumin; Jo, Hyeonjeong; Khazi, Mohammed Iqbal; Hwang, Hyemin; Lee, Dong Geol; Kim, Jong-Man Abstract: Polydiacetylenes (PDAs) have attracted significant attention as promising materials for sensor development due to their unique colorimetric and fluorescent responses to external stimuli. In this study, we propose a PDA-based sensor structure capable of selectively detecting ammonia, developed from a diacetylene monomer functionalized with a cytosine moiety (CyDA). By inducing hemi-protonation, we established a CyDA-H platform that enables colorimetric ammonia sensing. Furthermore, instead of conventional film-casting or drop-casting methods, we employed an electrospinning technique to overcome the limitation of low sensitivity. CyPDA-H was immobilized within a three-dimensional porous polyethylene oxide (PEO) nanofibrous matrix via electrospinning, enhancing reactivity with ammonia molecules. The resulting sensor exhibited a low detection limit of 17 ppm and demonstrated excellent selectivity for ammonia over various amines and basic compounds. Additionally, real-time monitoring of raw chicken spoilage at 4 °C and 25 ℃ revealed a gradual color change from blue to red due to the accumulation of ammonia released during decomposition, which was clearly visible to the naked eye. This study successfully demonstrates the fabrication of a highly sensitive electrospun-type CyPDA-H sensor and highlights its strong potential for commercial application as a simple and easy-to-use food freshness indicator. 2026-09-01T00:00:00Z