• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.233-239
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• 2021

Cyanobacteriochromes (CBCRs) are phytochrome-related photoreceptor proteins in cyanobacteria and cover a wide spectral range from ultraviolet to far-red. A single GAF domain that they contain can bind bilin(s) autocatalytically via heterologous recombination and then fluoresce, with potential applications as biomarkers and biosensors. Here, we report that a novel red/green CBCR GAF domain, SPI1085g2 from Spirulina subsalsa, covalently binds both phycocyanobilin (PCB) and phycoerythrobilin (PEB). The PCB-binding GAF domain exhibited canonical red/green photoconversion with weak fluorescence emission. However, the PEB-binding GAF domain, SPI1085g2-PEB, exhibited an intense orange fluorescence (λabs.max = 520 nm, λfluor.max = 555 nm), with a fluorescence quantum yield close to 1.0. The fluorescence of SPI1085g2-PEB was selectively and instantaneously quenched by copper ions in a concentration-dependent manner and exhibited reversibility upon treatment with the metal chelator EDTA. This study identified a novel PEB-binding cyanobacteriochrome-based fluorescent protein with the highest quantum yield reported to date and suggests its potential as a biosensor for the rapid detection of copper ions.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.336-338
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• 2015

This research is to propose an applicable framework for real-time health surveillance and safety monitoring at construction sites. First this study aims at finding (1) a framework for health surveillance that is likely to benefit employers and employees in the industry, (2) a valid way to identify factors or conditions with potential health concerns that can occur under particular work conditions, (3) An effective way to apply wireless/mobile sensors to construction workers using real-time/live data transmission methods, and (4) A relationship between a worker's vital signs and job site environment. Biosensors for physiological response and devices for weather/work related data are to collect real-time data. Relationships between jobs and physiological responses are analyzed and factors that touched particularly contributing to certain responses are identified. When data are incorporated with tasks, factors affecting tasks can be identified to estimate the magnitude of the factors. By comparing work and normal responses possible precautionary actions can be considered. In addition, the study would be lead to improving (1) trade-specific dynamic work schedules for workers which would be based on various factors affecting worker health level and (2) reevaluating worker productivity with health status and work schedule, thereby seeking ways to maximize worker productivity. Through a study, the paper presents expected benefits of implementing health monitoring.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.387-396
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• 2020

Wearable biosensors have the potential to non-invasively and continuously monitor seniors' stress in their daily interaction with the urban environment, thereby enabling to address the stress and ultimately advance their outdoor mobility. However, current wearable biosensor-based stress detection methods have several drawbacks in field application due to their dependence on batch-learning algorithms. First, these methods train a single classifier, which might not account for multiple subjects' different physiological reactivity to stress. Second, they require a great deal of computational power to store and reuse all previous data for updating the signle classifier. To address this issue, we tested the feasibility of online multi-task learning (OMTL) algorithms to identify multiple seniors' stress from electrodermal activity (EDA) collected by a wristband-type biosensor in a daily trip setting. As a result, OMTL algorithms showed the higher test accuracy (75.7%, 76.2%, and 71.2%) than a batch-learning algorithm (64.8%). This finding demonstrates that the OMTL algorithms can strengthen the field applicability of the wearable biosensor-based stress detection, thereby contributing to better understanding the seniors' stress in the urban environment and ultimately advancing their mobility.

• 산업기술연구
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• 제43권1호
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• pp.25-31
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• 2023

Stretchable and flexible electronics that comply with dynamic movements and micromotion of the human tissues can enable real-time monitoring of physiologic signals onto the human skin and in the brain, respectively. Especially, gallium based liquid metal stretchable electronics can offer human-interactive biosensors to monitor various physiologic parameters. However, the liquid-like nature, surface oxidation and contamination by organic materials, and low biostability of the liquid metals have still limited the long-term use as bioelectronics. Here we introduced electrochemical deposition without oxidation pathways to overcome these practical challenges in liquid metal bioelectronics. CNT/PDDA composite with reduction way and PEDOT:BF₄ with oxidation way under organic solvent are suggested as rationally designed material engineering approaches. We confirmed that the structures with the soft, flexible, and stretchable liquid metal platform can successfully detect dopamine with a high sensitivity and selectivity, record neural signals including action potentials without scar formation, and monitor physiologic signals such as EMG and ECG.

• 전기화학회지
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• 제11권3호
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• pp.170-175
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• 2008

다중 생체시료 검출을 위한 바이오센서 연구를 위하여 각기 두 전위를 갖는 오스뮴 고분자를 함께 탄소 전극 (Screen Printed Carbon Electrodes) 위에 고정하였다. 새로운 개념의 다중 생체시료 검출 바이오센서 연구위하여 과산화수소의 환원과 글루코스의 산화에 관여하는 환원 효소와 산화 효소를 각각 이용하였다. 실험 목적에 위하여 염소 작용기 ($E^{O'}$ + 0.520 vs. Ag/AgCl)와 메톡시 작용기 ($E^{O'}$ + 0.150 vs. Ag/AgCl)를 각각 포함하는 두 개의 오스뮴 고분자를 합성하였다. 전자는 과산화수소의 환원에 대하여 좋은 촉매전류신호를 보였고, 후자는 당의 산화에 대하여 효과적인 촉매전류신호를 보였다.

• 전기화학회지
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• 제11권2호
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• pp.105-108
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• 2008

최근, 증폭되는 관심은 창조적인 방법에 따른 CNTs의 합리적인 기능화에 집중하고 있다. 하지만 CNTs의 적지 않은 독성은 아직 논쟁의 이슈가 되어 그 생물학적 응용이 제한되어왔다. CNT의 생체 적합성을 개선하기 위해 본 연구에서는 CNT와 유기적인 티타늄을 시작 물질로 나노 혼성의 CNT-$TiO_2$를 제조하여 전기화학적 거동을 고찰하였다. 본 연구는 개질 된 접촉면이 이질의 전자 전송율을 가속하고, 그 결과, 관련 검출감도를 강화할 수 있었음을 확인하였다. 또한 암의 초기 진단을 위한 생물학적 적합성으로 멀티신호의 민감한 바이오센서의 개발에 새로운 전략으로서 그 잠재력의 응용을 제안하고자 한다.

• 한국환경농학회지
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• 제29권1호
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• pp.72-76
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• 2010

본 연구에서는 탄소 유기물과 CoPh를 혼합하여 농약 잔류량을 측정 할 수 있는 바이오센서를 구현 하였다. 작동 전극은 탄소유기물과 CoPh를 섞어 사용하였고 비율은 CoPh를 7%로 제작하였다. CoPh가 7%인 경우 저농도 thiocholine 농도에서도 민감하게 반응하였다. 대표적인 농약인 카보후란에 대하여 센서의 감도 한계는 약$0.5{\mu}g/L$ 수준이며, 농약 농도에 따른 전극의 출력이 선형적인 결과를 얻었다. 또한 EPN 및 클로로피리포스 농약에 대하여 실험 한 결과 카보후란과 같이 농도에 따라 효과적으로 반응하는 것을 확인하였다. 이러한 센서는 현재 농약 잔류량 측정에 사용되는 비색법과 비교하여도 감도 및 선형성 면에서 뒤떨어지지 않으며, 간이 농약 잔류량 측정기 센서로 사용가능성이 있다.

• 대한기계학회논문집A
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• 제31권10호
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• pp.986-992
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• 2007

This paper presents the fabrication and characterization of carbon films pyrolyzed with various photoresists for bioMEMS applications. To verify the usefulness of pyrolyzed carbon films as an electrode material in an electrochemical biosensor developed by the authors, interactions between avidin and biotin on the pyrolyzed carbon film were studied via electrochemical impedance spectroscopy based on electrostatic interactions between avidin and negatively-charged ferricyanide. The pyrolyzed carbon films were characterized using a surface profiler, a precision semiconductor parameter analyzer, a nanoindentor, scanning electron microscopy, and atomic force microscopy. Amine conjugated biotin was immobilized on the electrode using EDC/NHS as crosslinkers after $O_2$ plasma treatment to enhance functional groups on the carbon electrode pyrolyzed at $1000^{\circ}C$ with AZ9260. The detection of avidin binding with different concentrations in a range of 0.75 nM to $7.5\;{\mu}M$ to the pyrolyzed carbon electrode modified with biotin was carried out by measuring the electrochemical impedance change. The results show that avidin binds to the biotin on the electrode not by non-specific interaction but by specific interaction, and that EIS successfully detects this binding event. Pyrolyzed carbon films are a promising material for miniaturization, integration, and low-cost fabrication in electrochemical biosensors.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.393-393
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• 2012

Optically active nanostructures such as subwavelength moth-eye antireflective structures or surface enhanced Raman spectroscopy (SERS) active structures have been demonstrated to provide the effective suppression of unwanted reflections as in subwavelength structure (SWS) or effective enhancement of selective signals as in SERS. While various nanopatterning techniques such as photolithography, electron-beam lithography, wafer level nanoimprinting lithography, and interference lithography can be employed to fabricate these nanostructures, roll-to-roll (R2R) nanoimprinting is gaining interests due to its low cost, continuous, and scalable process. R2R nanoimprinting requires a master to produce a stamp that can be wrapped around a quartz roller for repeated nanoimprinting process. Among many possibilities, two different types of mask can be employed to fabricate optically active nanostructures. One is self-assembled Au nanoparticles on Si substrate by depositing Au film with sputtering followed by annealing process. The other is monolayer silica particles dissolved in ethanol spread on the wafer by spin-coating method. The process is optimized by considering the density of Au and silica nano particles, depth and shape of the patterns. The depth of the pattern can be controlled with dry etch process using reactive ion etching (RIE) with the mixture of SF6 and CHF3. The resultant nanostructures are characterized for their reflectance using UV-Vis-NIR spectrophotometer (Agilent technology, Cary 5000) and for surface morphology using scanning electron microscope (SEM, JEOL JSM-7100F). Once optimized, these optically active nanostructures can be used to replicate with roll-to-roll process or soft lithography for various applications including displays, solar cells, and biosensors.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.47-47
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• 2005

There are many different surface technologies currently applied for preparation of protein chips. However, it requires innovative surface chemistry for capture proteins to be immobilized on chip surface keeping their conformation and activity intact and their orientation right, while they bind tightly and densely in a given array spot. Proteogen has developed 'ProteoChip BP' coated with novel proprietary linker molecules $(ProLinker^{TM})$ for efficient and robust immobilizations of capture proteins by improving surface properties of molecular captures. It was demonstrated that $ProLinker^{TM}$ gave the best surface performance in preparation of protein microarray chip base plates among others currently available on the market. In particular, the $ProLinker^{TM}-based$ surface chemistry has demonstrated to provide excellent performance in preparation of 'Antibody Chip' for analysis of biomarkers as well as proteome expression profiles. The linker molecule has also shown to be well applicable for development of biosensors and micro-beads as well as protein microarray and nano-array. ProteoChip BP can be used either for preparation of high-density array by using a microarrayer or for preparation of 'Well-on-a-Chip' with low density array, which is better applicable for quantitative analysis of biomarkers or protein-protein interactions. The biomarker assay can be performed either by direct or sandwich methods of fluorescence immunoassay. Application of ProteoChip BP has been well demonstrated by the extensive studies of 1) tumor-marker assays, 2) new drug screening by using 'Integrin Chip' and 3) protein expression profile analysis. Some of experimental results will be presented.