• 한국잠사곤충학회지
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• 제43권2호
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• pp.109-115
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• 2001

실크 세리신 단백질을 추출정제하여 새로운 기능성 소재로 활용하기 위하여 세리신 추출법에 따른 세리신의 특성을 분석하고 약리효능과 피부친화성 소재로의 응용 가능성을 관능평가를 통하여 조사한 결과 다음과 같은 결론을 얻었다. 1. 실크 세리신 단백질을 효과적으로 추출하는 방법은 NaOH(0.02wt.%)로 처리하는 방법과 질소공기 하에서 식용효소인 Flavourzyme 3%로 처리하는 방법이 연감을 25wt.% 내외로 거의 100% 세리신을 회수하였다. 2. 추출된 세리신의 분자량 분포는 10,000-30,000 범위였으며 용해도는 90 wt.% 이상이었다. 또한 Actinase 등 단백질 분해 효소로 처리하여 분자량 2,700-4,200 의 저분자화 세리신을 얻을 수 있었으나 아미노산 조성은 고온고압 추출 세리신과 큰 차이가 없었다. 3.세리신의 항산화, 혈당강하 및 알콜대사에 미치는 영향을 살펴본 결과 유의성 있는 항산화 효과를 나타내지는 않았으나 세리신 투여시 sucrose와 maltose에 의하여 유발되는 혈당을 각각 62.6%, 41.5% 낮추는 효과를 나타내었다. 4. 피부친화성 소재로서 세리신의 활용가능성을 검토하기 위하여 중금속 함량을 측정한 결과 활성탄이나 wool filter를 이용함으로서 효과적으로 중금속을 제거할 수 있었으며, 세리신을 포함한 비누와 입욕제에 대한 관능평가 결과 세정력, 기포성, 세면후 피부보습성 등이 우수한 것으로 판정되어 실크 세리신 단백질은 피부친화성 미용 소재로 적용이 가능할 것으로 확인되었다.

• 센서학회지
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• 제31권2호
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• pp.71-78
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• 2022

Wearable devices have the potential to revolutionize future medical diagnostics and personal healthcare. The integration of biosensors into scalable form factors allow continuous and noninvasive monitoring of key biomarkers and various physiological indicators. However, conventional wearable devices have critical limitations owing to their rigid and obtrusive interfaces. Recent developments in functional biocompatible materials, micro/nanofabrication methods, multimodal sensor mechanisms, and device integration technologies have provided the foundation for novel skin-interfaced bioelectronics for advanced and user-friendly wearable devices. Nonetheless, it is a great challenge to satisfy a wide range of design parameters in fabricating an authentic skin-interfaced device while maintaining its edge over conventional devices. This review highlights recent advances in skin-compatible materials, biosensor performance, and energy-harvesting methods that shed light on the future of wearable devices for digital health and personalized medicine.

• 센서학회지
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• 제32권6호
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• pp.335-339
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• 2023

Skin-compatible electronics have evolved to achieve both conformality and stretchability for stable contact with deformable biological skin. While existing research has largely concentrated on alternative materials, the potential of Parylene-based thin-film electrodes for stretchable on-skin applications remains relatively untapped. This study proposes an engineering strategy to achieve stretchability using the Parylene thin-film electrode. Unlike the conventional Parylene thin-film electrode, we introduce morphological adaptability via controlled microscale slits in the Parylene electrode structure. The slits-containing device enables unprecedented stretchability while maintaining critical electrical insulation properties during mechanical deformation. Finally, the demonstration on human skin shows the mechanical adaptability of these Parylene-based bioelectrodes while their electrical characteristics remain stable during various stretching conditions. Owing to the ultra-thinness of the Parylene coating, the wearable bioelectrode not only achieves stretchability but also conforms to the skin. Our findings broaden the practical use of Parylene thin-film bioelectrodes.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.10.1-10.1
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• 2011

Energy harvesting technologies converting external sources (such as thermal energy, vibration and mechanical energy from the nature sources of wind, waves or animal movements) into electrical energy is recently a highly demanding issue in the materials science community for making sustainable green environments. In particular, fabrication of usable nanogenerator attract the attention of many researchers because it can scavenge even the biomechanical energy inside the human body (such as heart beat, blood flow, muscle stretching, or eye blinking) by converging harvesting technology with implantable bio-devices. Herein, we describe procedure suitable for generating and printing a lead-free microstructured $BaTiO_3$ thin film nanogenerator on plastic substrates to overcome limitations appeared in conventional flexible ferroelectric devices. Flexible $BaTiO_3$ thin film nanogenerator was fabricated and the piezoelectric properties and mechanically stability of ferroelectric devices were characterized. From the results, we demonstrate the highly efficient and stable performance of $BaTiO_3$ thin film nanogenerator and the integration of bio-eco-compatible ferroelectric materials may enable innovative opportunities for artificial skin and energy harvesting system.

• Bulletin of the Korean Chemical Society
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• 제24권4호
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• pp.499-503
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• 2003

Encapsulation of L-ascorbic acid (vitamin C) within a bio-compatible layered inorganic material was achieved by coprecipitation reaction, in which the layered inorganic lattice and its intercalate of vitamin C are simultaneously formed. The nano-meter sized powders of vitamin C intercalate thus prepared was again encapsulated with silica nano-sol to form a nanoporous shell structure. This ternary nanohybrid of vitamin Clayered inorganic core-$SiO_2$ shell exhibited an enhanced storage stability and a sustained releasing of vitamin C. Furthermore, the nano-encapsulation of vitamin C with inorganic mineral was very helpful in delivering vitamin C molecules into skin through stratum corneum, facilitating transdermal penetration of vitamin C in topical application.

• Journal of Semiconductor Engineering
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• 제1권3호
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• pp.88-98
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• 2020

As biosensors are widely used in the medical field, flexible devices compatible with live animals have aroused great interest. Especially, significant research has been carried out to develop implantable or skin-attachable devices for real-time bio-signal sensing. From the device point of view, various biosensor types such as field-effect transistors (FETs) and multi-electrode arrays (MEAs) have been reported as diverse sensing strategies. In particular, the flexible FETs and MEAs allow semiconductor engineering to expand its application, which had been impossible with stiff devices and materials. This review summarizes the state-of-the-art research on flexible FET and MEA biosensors focusing on their materials, structures, sensing targets, and methods.

• 대한의용생체공학회:의공학회지
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• 제29권1호
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• pp.59-65
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• 2008

Nowadays, implantable hearing aids have been developed to solve the problems of conventional hearing aids. In case of fully implantable hearing aids, an implantable microphone is necessary to receive sound signal beneath the skin. Normally, an implantable microphone has poor frequency response characteristics in high frequency bands of acoustic signal due to the high frequency attenuation effect of skin after implantation to human body. In this paper, the implantable microphone is designed to reduce the high frequency attenuation effect of a skin by putting its resonance frequency at the attenuated range through a finite element analysis (FEA) simulation. The designed implantable microphone through the simulated results has been fabricated by manufacturing process using bio-compatible materials. By the several in-vitro experiments with pig skin, it has been verified that the designed implantable microphone has a resonance frequency around the starting part of the attenuated range and reduces the attenuation effect.

• Elastomers and Composites
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• 제58권3호
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• pp.112-120
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• 2023

Herein, we propose a facile water-processible method to develop an eggshell membrane (ESM)-embedded waterborne polyurethane (WPU)-based bio-degradable and bio-compatible coating material that exhibits attractive tactile properties. Virgin ESM is not dispersible in water. Hence, to develop the ESM-based WPU composite, soluble ESM (S-ESM) was first extracted by de-crosslinking the ESM. The extracted S-ESM at different concentrations (0, 0.5, 1.0, 1.5 wt %) was mixed with WPU. Compared to virgin WPU, the viscosity of S-ESM/WPU dispersion and the in-plane coefficient of friction (COF) of the composite film surfaces decreased with an increase in the S-ESM content. In addition, an increase in the S-ESM content improved the tribo-positive characteristics of the film. Different good touch-feeling biomaterials, such as fur, feather, and human skin exhibit tribo-positivity. Thus, the enhanced tribo-positive characteristics of the S-ESM/WPU and the decrease in their COF owing to an increase in the S-ESM content imply the enhancement of its touch-feeling performance. The S-ESM embedded WPU composites have potential applications as coating materials in various fields, including automobile interiors and artificial leather.

• Composites Research
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• 제22권3호
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• pp.55-59
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• 2009

마이크로스트림 안테나는 가볍고 부피가 작을 뿐만 아니라 집적화가 가능하고, 표면 부착력이 탁월하여 많은 통신 시스템 안테나로 응용되고 있다. 안테나의 구조는 12.5GHz의 중심주파수를 갖는 사각 패치 마이크로 스트립 안테나로 설계하였고 곡률 방향으로 패치를 확장시켜 총 4개의 패치를 배열시켰다. 양쪽의 복합재료 사이에 허니컴을 삽입한 샌드위치 구조물이 되도록 설계한 다음 충격 실험을 실시하였다. 충격실험 후 안테나 성능변화를 측정한 결과 영향을 받지 않는다는 것을 확인하였다.