1,720,963 research outputs found
Implantable Photovoltaic Cell Using Upconversion Nanoparticles for On-Demand Drug Delivery Devices
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Upconversion Nanoparticles/HA-Rose Bengal Conjugate Complex for Noninvasive Photochemical Tissue Bonding
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Upconversion Nanoparticles / Hyaluronate-Rose Bengal Conjugate Complex for Noninvasive Photochemical Tissue Bonding
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Upconversion nanoparticles / hyaluronate-rose bengal conjugate complex for noninvasive photochemical tissue bonding
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Hyaluronate and Its Derivatives for Customized Biomedical Applications
No full textSince hyaluronate (HA) was firstly isolated from the vitreous of bovine eyes in 1934, HA has been widely
investigated for various biomedical applications. As a naturally-occurring polysaccharide, HA has been
used for joint lubrication and ocular treatment in its intact form due to the excellent biocompatibility,
viscoelasticity, biodegradability, and hygroscopic properties. HA can be easily functionalized via the
chemical modification of its carboxyl and hydroxyl groups. Recently, a variety of biological functions of
HA have been explored and a number of customized applications have been investigated taking advantages
of the interaction between HA and biological tissues. HA has been used for drug delivery to
enhance the blood circulation time of drugs with target-specificity to HA receptors in the body. HA has
been also used to prepare tissue engineering hydrogel scaffolds for the spatiotemporal control of
encapsulated cells. In this review, we describe the key biological functions of HA in the body in terms of
its structure, physical properties, biodistribution and interaction with HA receptors. After that, we
describe unique advantages that allow HA to be applied in various biomedical fields. Finally, we report
the conventional and newly emerging applications of HA and its derivatives under commercial development
stages.1114sciescopu
Organic Transistor-Based Chemical Sensors for Wearable Bioelectronics
No full textCONSPECTUS: Bioelectronics for healthcare that monitor the health information on users in real time have stepped into the limelight as crucial electronic devices for the future due to the increased demand for "point-of-care" testing, which is defined as medical diagnostic testing at the time and place of patient care. In contrast to traditional diagnostic testing, which is generally conducted at medical institutions with diagnostic instruments and requires a long time for specimen analysis, point-of-care testing can be accomplished personally at the bedside, and health information on users can be monitored in real time. Advances in materials science and device technology have enabled next-generation electronics, including flexible, stretchable, and biocompatible electronic devices, bringing the commercialization of personalized healthcare devices increasingly within reach, e.g., wearable bioelectronics attached to the body that monitor the health information on users in real time. Additionally, the monitoring of harmful factors in the environment surrounding the user, such as air pollutants, chemicals, and ultraviolet light, is also important for health maintenance because such factors can have short- and long-term detrimental effects on the human body. The precise detection of chemical species from both the human body and the surrounding environment is crucial for personal health care because of the abundant information that such factors can provide when determining a person's health condition. In this respect, sensor applications based on an organic-transistor platform have various advantages, including signal amplification, molecular design capability, low cost, and mechanical robustness (e.g., flexibility and stretchability). This Account covers recent progress in organic transistor-based chemical sensors that detect various chemical species in the human body or the surrounding environment, which will be the core elements of wearable electronic devices. There has been considerable effort to develop high-performance chemical sensors based on organic-transistor platforms through material design and device engineering. Various experimental approaches have been adopted to develop chemical sensors with high sensitivity, selectivity, and stability, including the synthesis of new materials, structural engineering, surface functionalization, and device engineering. In this Account, we first provide a brief introduction to the operating principles of transistor-based chemical sensors. Then we summarize the progress in the fabrication of transistor-based chemical sensors that detect chemical species from the human body (e.g., molecules in sweat, saliva, urine, tears, etc.). We then highlight examples of chemical sensors for detecting harmful chemicals in the environment surrounding the user (e.g., nitrogen oxides, sulfur dioxide, volatile organic compounds, liquid-phase organic solvents, and heavy metal ions). Finally, we conclude this Account with a perspective on the wearable bioelectronics, especially focusing on organic electronic materials and devices.11sciescopu
프리즘 홀로그래피 식각공정을 이용한 우드파일 광결정과 인코드된 내부 우드파일 구조를 갖는 광결정 입자의 제조
No full text학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2010.2, [ vi, 60 p. ]In part one, we demonstrate the use of (4+1)-beam holographic interference lithography technique to fabricate woodpile structures in negative photoresists by using single refracting fused silica prism. Top-cut pyramid prism substitutes complicated optical setups for splitting the laser output into multiple beams, and then superposing them at the exposure area, making it easily accessible experimentally. The fabricated woodpile structures are in good agreement with model simulations, and variable optical reflectance spectra can be obtained by controlling laser exposure intensity and photoacids generator concentration. Furthermore, woodpiles with the diamond-like symmetry are also obtained by exploiting the shrinkage of the photoresists, and photonic bandgaps in the visible range are observed with high reflection intensity.
In second part, a method to fabricate micron-scale photonic crystal arrays and freestanding particles with internal woodpile structures is described. Hot-embossing process using elastomeric molds defines a disk-like shape of microarrays and particles, and prism holographic interference lithography induces internal woodpile structures as an information identifier consisting of different reflectance peak position. Freestanding microparticles with internal nanostructures are released from microarrays on a plate by dissolution of a sacrificial layer. Also fluorescence enhancement with fluorescent dye is examined, and immobilization of biomolecules via chemical surface modification of the particles is demonstrated.한국과학기술원 : 생명화학공학과
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