Publications by authors named "Jun Seop Lee"

Effective enzyme stabilization through immobilization is essential for the functional usage of enzymatic reactions. We propose a new method for synthesizing elastic hydroxyapatite microgel (E-HAp-M) materials and immobilizing lipase using this mesoporous mineral via the ship-in-a-bottle-neck strategy. The physicochemical parameters of E-HAp-M were thoroughly studied, revealing that E-HAp-M provides efficient space for enzyme immobilization.

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Dynamic bonds can facilitate reversible formation and dissociation of connections in response to external stimuli, endowing materials with shape memory and self-healing capabilities. Temperature is an external stimulus that can be easily controlled through heat. Dynamic covalent bonds in response to temperature can reversibly connect, exchange, and convert chains in the polymer.

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In addressing the increasing demand for wearable sensing systems, the performance and lifespan of such devices must be improved by enhancing their sensitivity and healing capabilities. The present work introduces an innovative method for synthesizing a healable disulfide bond contained in a polydimethylsiloxane network (PDMS-SS) that incorporates ionic salts, which is designed to serve as a highly effective dielectric layer for capacitive tactile sensors. Within the polymer network structure, the cross-linking agent pentaerythritol tetrakis 3-mercaptopropionate (PTKPM) forms reversible disulfide bonds while simultaneously increasing polymer softness and the dielectric constant.

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Portal vein tumor thrombosis (PVTT) is an uncommon condition in which tumor cells expand into the vessels, causing blood clot formation in the portal vein. PVTT is mainly associated with hepatocellular carcinoma, leading to an unfavorable prognosis; however, it can also develop in patients with other cancer types. Herein, we report a case of metastatic renal cell carcinoma diagnosed by a blind liver biopsy in a patient with dynamic computed tomography-confirmed portal vein thrombosis and cholangiopathy.

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Nanofibers have gained much attention because of the large surface area they can provide. Thus, many fabrication methods that produce nanofiber materials have been proposed. Electrospinning is a spinning technique that can use an electric field to continuously and uniformly generate polymer and composite nanofibers.

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Article Synopsis
  • The rise of wearable sensors has led to interest in their use for motion-based health care, but challenges remain due to their size and rigidity.
  • Research is focused on developing small, flexible tactile sensors that can accurately gather data from body movements, enhancing their practicality and functionality.
  • The review covers various tactile sensor types (piezoresistive, piezocapacitive, piezoelectric, triboelectric) and explores their applications in health monitoring, AI, and human behavior studies.
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Nesfatin-1 (NES1) is a potential biomarker found in serum and saliva that indicates hyperpolarization and depolarization in the hypothalamic ventricle nucleus as well as an increase in epileptic conditions. However, real-time investigations have not been carried out to detect changes in the concentration of NES1. In this study, we develop a multiscale pore contained carbon nanofiber-based field-effect transistor (FET) biosensor to detect NES1.

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In this work, we report a facile way to control crystalline structures of polyketone (PK) films by combining plasma surface treatment with chemical vapor deposition (CVD) technique. The crystalline structure of PKs grown on plasma-treated graphene and the resulting thermal and mechanical properties were systematically discussed. Every graphene sheet used in this work was produced by CVD method and the production of PKs having different crystallinity were performed on the O- and N-doped graphene sheets.

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Research on wearable sensor systems is mostly conducted on freestanding polymer substrates such as poly(dimethylsiloxane) and poly(ethylene terephthalate). However, the use of these polymers as substrates requires the introduction of transducer materials on their surface, which causes many problems related to the contact with the transducer components. In this study, we propose a freestanding flexible sensor electrode based on a β-MnO-decorated carbon nanofiber sheet (β-MnO@CNF) to detect dimethyl methylphosphonate (DMMP) as a nerve agent simulant.

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Despite being highly flammable at lower concentrations and causing suffocation at higher concentrations, hydrogen gas continues to play an important role in various industrial processes. Therefore, an appropriate monitoring system is crucial for processes that use hydrogen. In this study, we found a nanocomposite comprising of ruthenium nanoclusters decorated on carboxyl polypyrrole nanoparticles (Ru_CPPy) to be successful in detecting hydrogen gas through a simple sonochemistry method.

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Research on flexible biosensors is mostly focused on their use in obtaining information on physical signals (such as temperature, heart rate, pH, and intraocular pressure). Consequently, there are hardly any studies on using flexible electronics for detecting biomolecules and biomarkers that cause diseases. In this study, we propose a flexible, three-dimensional carbon nanoweb (3DCNW)-based aptamer sensor to detect the platelet-induced growth factor (PDGF), which is an oncogenic biomarker.

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Considering their superior electrochemical performances, extensive studies have been carried out on composite nanomaterials based on porous carbon nanofibers. However, the introduction of inorganic components into a porous structure is complex and has a low yield. In this study, we propose a simple synthesis of cobalt-oxide-incorporated multichannel carbon nanofibers (P-Co-MCNFs) as electrode materials for electrochemical applications.

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Investment in wearable monitoring systems is increasing rapidly for realizing their practical applications, for example, in medical treatment, sports, and security systems. However, existing wearable monitoring systems are designed to measure a real-time physical signal and abnormal conditions rather than harmful environmental characteristics. In this study, a flexible chemical sensor electrode based on a three-dimensional conductive nanofilm (3D CNF) is fabricated via facile polymerization with temperature control.

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Article Synopsis
  • Solution-processable conducting polymers, especially polyaniline (PANI) composites, are gaining attention for creating thin-film electrodes with customizable thickness and superior properties like high conductivity and excellent electrochemical performance.
  • This review covers basic principles, different fabrication methods, and a variety of applications for PANI composites, including uses in solar cells, electrochromic windows, thermoelectric materials, and more.
  • Recent research examples aim to enhance the design and production of high-performance electrodes from PANI composites for advanced technological applications.
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Poly(4-styrenesulfonate)-conducting polymer (PSS-CP) is advantageous for thin-film electrode manufacturing due to its high conductivity, high charge storage, structural stability, and excellent ink dispersion. In this work, comparative studies of two-electrode symmetric supercapacitors using Polypyrrole:Poly(4-styrenesulfonate) (PPy:PSS), with different molecular weights ('s) of Poly(4-styrenesulfonate) (PSS) as the electrodes, were performed. PPy:PSS can be easily prepared using a simple solution process that enables the mass production of thin-film electrodes with improved electrical and electrochemical properties.

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Article Synopsis
  • Recent advancements in flexible energy devices have improved power for portable electronics, but traditional rigid components limit their potential.
  • A new method developed for fabricating porous polyaniline composites shows significant improvements in specific capacitance and electrical conductivity compared to standard films.
  • The porous structure enhances performance by increasing the active surface area for interactions with electrolyte ions, making this technique valuable for large-scale electrochemical applications.
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Background: Cytomegalovirus (CMV) is a common viral pathogen in transplant patients which often targets the stomach. However, the endoscopic characteristics of gastric CMV infection are not well established. We aimed to develop a predictive model using endoscopic findings for gastric CMV infection in renal transplant patients.

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Hydrogen sulfide (HS) is one of the most plentiful toxic gases in a real-life and causes a collapse of the nervous system and a disturbance of the cellular respiration. Therefore, highly sensitive and selective HS gas sensor systems are becoming increasingly important in environmental monitoring and safety. In this report, we suggest the facile synthesis method of the FeO particles uniformly decorated on carbon nanotubes (FeO@CNT) to detect HS gas using oxidative co-polymerization (pyrrole and 3-carboxylated pyrrole) and heat treatment.

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Hepatitis B virus (HBV) infection is a major worldwide health issue causing serious liver diseases, including liver cirrhosis and hepatocellular carcinoma. Monitoring the serum hepatitis B surface antigen (HBsAg) level is pivotal to the diagnosis of HBV infection. In this study, we describe multidimensional conductive nanofilm (MCNF)-based field-effect transistor (FET) aptasensor for HBsAg detection.

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Oxalic acid (OA), naturally available in many fruits and vegetables, reacts easily with Ca and Mg ions to produce an insoluble salt. In renal systems, this insoluble salt brings about various renal diseases. As such, the OA excretion level in urine has been utilized as an index parameter in healthcare settings.

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Dopamine (DA), a catecholamine hormone, is an important neurotransmitter that controls renal and cardiovascular organizations and regulates physiological activities. Abnormal concentrations of DA cause unfavorable neuronal illnesses such as Parkinson's disease, schizophrenia, and attention deficit hyperactivity disorder/attention deficit disorder. However, the DA concentration is exceedingly low in patients and difficult to detect with existing biosensors.

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Activated highly porous carbon nanotubes are synthesized with a facile dual-nozzle co-electrospinning and a redox process to apply the framework of a sulfur-immobilized composite as a high-performance cathode in lithium-sulfur batteries.

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Due to rapid advances in technology which have contributed to the development of portable equipment, highly sensitive and selective sensor technology is in demand. In particular, many approaches to the modification of wireless sensor systems have been studied. Wireless systems have many advantages, including unobtrusive installation, high nodal densities, low cost, and potential commercial applications.

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In the development of disease diagnoses, rapid responses to and accurate selectivity for target analytes are critical aspects. As one diagnostic approach, biosensors with high sensitivity and selectivity are investigated to detect disorder factors (e.g.

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