4,181 research outputs found
WSO884517 Supplemental Material - Supplemental material for Characteristics and management of stroke in Korea: 2014–2018 data from Korean Stroke Registry
No full textSupplemental material, WSO884517 Supplemental Material for Characteristics and management of stroke in Korea: 2014–2018 data from Korean Stroke Registry by Han-Yeong Jeong, Keun-Hwa Jung, Heejung Mo, Chan-Hyuk Lee, Tae Jung Kim, Jong-Moo Park, MiSun Oh, Ji Sung Lee, Beom Joon Kim, Joon-Tae Kim, Jinkwon Kim, Woo-Keun Seo, Jun Lee, Jae-Kwan Cha, Sang-Bae Ko, Hee-Joon Bae and Byung-Woo Yoon in International Journal of Stroke</p
Complex coacervates based on recombinant mussel adhesive proteins: their characterization and applications
No full textComplex coacervates are a dense liquid phase of oppositely charged polyions formed by the associative separation of a mixture of polyions. Coacervates have been widely employed in many fields including the pharmaceutical, cosmetic, and food industries due to their intriguing interfacial and bulk material properties. More recently, attempts to develop an effective underwater adhesive have been made using complex coacervates that are based on recombinant mussel adhesive proteins (MAPs) due to the water immiscibility of complex coacervates and the adhesiveness of MAPs. MAP-based complex coacervates contribute to our understanding of the physical nature of complex coacervates and they provide a promising alternative to conventional invasive surgical repairs. Here, this review provides an overview of recombinant MAP-based complex coacervations, with an emphasis on their characterization and the uses of such materials for applications in the fields of biomedicine and tissue engineering.113sciescopu
Stem cell-loaded adhesive immiscible liquid for regeneration of myocardial infarction
No full textMyocardial infarction (MI) causes serious loss of cardiac muscle and dysfunction. To restore MI, exogenous stem cells should be efficiently delivered. However, due to severe physical and physiological cardiac environment, recent strategies have faced challenges, including low cell persistence, low integration, and delayed therapeutic effects. Herein, we proposed mesenchymal stem cell (MSC) therapeutic platform using adhesive protein-based immiscible condensed liquid system (APICLS) derived from bioengineered mussel adhesive protein (MAP). With high encapsulation efficiency and survival rate of encapsulated MSCs, APICLS was successfully grafted by intramyocardial injection and distributed throughout the scarred myocardium. Its underwater adhesiveness and biocompatibility fostered integration with damaged tissue, resulting in high cell persistence and maximized paracrine effects. Bioactive molecules released from APICLS with MSCs induced angiogenesis and cardioprotection, delayed cardiac remodeling, reduced fibrosis, and recovered contractive force. Thus, our proposed strategy represents an innovative approach for recovering infarcted cardiac tissues with damaged structural and contractive function.11Nsciescopu
Improved magnetic relaxivity via hierarchical surface structure of dysprosium-engineered superparamagnetic iron oxide nanoparticles in ultra-high magnetic field
No full textTo date, it is unknown whether the combination of Dy ions and superparamagnetic iron oxide (SPIO: Fe3O4) NPs can offer improved performance in UHF-MRI. In this work, we provide a paradigm of hierarchical surface-structured (His) DyxFe3-xO4 NPs as T-2 MRI nanoprobes at UHF (9.4T). We found that His-DyxFe3-xO4 NPs (x = 0.2) possess a higher transverse relaxivity than unmodified His-SPIO NPs and a significantly enhanced r(2)/r(1) ratio (up to10.4 times higher) than those of reported Dy-based T-2 MRI probes at 9.4 T. Furthermore, we demonstrate the effects of surface design of DyxFe3-xO4 NPs on their magnetic relaxivity and in vivo performance at UHF. The markedly enhanced r(2)/r(1) of His-DyxFe3-xO4 NPs (x = 0.2) at 9.4 T is mainly attributed to decreased r(1) relaxivity owing to the surface design and the possible disturbance of the Dy-Fe superexchange interaction. This work could provide an insightful strategy for the design of lanthanide-doped magnetic nanosystems as potential T-2 MRI nanoprobes in UHF. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.11Nsciescopuskc
Oriented in situ immobilization of a functional tyrosinase on microcrystalline cellulose effectively incorporates DOPA residues in bioengineered mussel adhesive protein
No full textBackground
Catechol-containing polymers such as mussel adhesive proteins (MAPs) are attractive as biocompatible adhesive biomaterials, and the catecholic amino acid 3,4-dihydroxyphenyl-L-alanine (DOPA) is considered a key molecule in underwater mussel adhesion. Tyrosinases can specifically convert tyrosine to DOPA without any cofactors. However, their catalytic properties still need to be adjusted to minimize unwanted DOPA oxidation via their diphenolase activity and catechol instability at neutral and basic pH values in the reaction products.
Methods and Results
In this work, we constructed a novel functional tyrosinase, mTyr-CNK_CBM, by fusion of mTyr-CNK with a cellulose-binding motif (CBM) for oriented in situ immobilization on microcrystalline cellulose via the C-terminal CBM without any additional purification steps. mTyr-CNK_CBM showed optimal catalytic activity at pH 4.5–6.5 and room temperature and had a high monophenolase/diphenolase activity ratio (Vmaxmono/Vmaxdi = 2.08 at pH 6 and 25°C). mTyr-CNK_CBM exhibited 2.17-fold higher (as a unimmobilized free enzyme) and similarly high (upon immobilization) in vitro DOPA modification of a bioengineered MAP compared to a commercially available mushroom tyrosinase. Moreover, the immobilized mTyr-CNK_CBM showed long-term storability and improved reusability.
Conclusions
These results clearly demonstrate a strong potential for practical use of immobilized mTyr-CNK_CBM as a monophenol monooxygenase in preparing biocompatible DOPA-tethered biomaterials and other catechol-containing polymers.11Nsciescopu
Marine-derived natural polymer-based bioprinting ink for biocompatible, durable, and controllable 3D constructs
No full text3D bioprinting (3DBP) is a rapid solid-form fabrication method with a high degree of automation and reproducibility for constructing structural bioscaffolds. However, the development of the 3DBP field has been slowed due to difficulty in acquiring suitable ink materials especially with natural polymers that satisfy all requirements, such as printability, mechanical integrity, and biocompatibility. In this study, a new 3DBP ink of bioengineered sea anemone-derived silk-like protein (aneroin) was used based on its durable mechanical properties and biodegradability in previous studies. The hyaluronic acid and mussel adhesive protein (MAP) were applied for improved printability and cell adhesiveness, respectively. The aneroin-based 3DBP ink (named aneroin ink) was solidified in a few second by dityrosine photo-crosslinking, and its fast reaction was suitable for noncollapsed spaces in printed 3D constructs. Actual-sized human ear, vascular graft, and rectangular multi-layered lattice were bioprinted with high controllability and durable structural integrity. Thus, the developed aneroin ink showed good printability, structural integrity, and biocompatibility for successful application to the construction of various 3D shaped bioscaffolds in tissue and biomedical engineering fields.11Nsciescopu
Halotolerant carbonic anhydrase with unusual N-terminal extension from marine Hydrogenovibrio marinus as novel biocatalyst for carbon sequestration under high-salt environments
No full textCarbonic anhydrase (CA), an enzyme that catalyzes the carbon dioxide (CO2) hydration, has been suggested as a potentially powerful agent for CO2 capture and utilization. For successful application, CA should withstand the harsh environment presented by CO2-capturing facilities. While there have been intensive efforts to identify and engineer thermostable CAs, other required conditions such as the high salt concentration of CO2 absorbents have often been ignored. Herein, we expressed, purified, and characterized a novel alpha-type CA (hmCA) possessing an unusual N-terminal extension from the halophilic marine bacterium Hydrogenovibrio marinus. We found that the N-terminal extension strongly influenced the enzyme solubility. Recombinant hmCA showed catalytic efficiency comparable to other bacterial alpha-type CAs. hmCA was less inhibited by anionic inhibitors showing 1.6- (NO3-), 3.1-(NO2-), and 3.7-fold (Cl-) higher inhibition constants than those of mesophilic bovine CA (bCA), suggesting halotolerance. Recombinant hmCA was markedly stabilized using most of the alkali metal salts tested, showing 19 degrees C higher melting temperature at 1 M NaCl compared to bCA that was significantly destabilized. The region of N-terminal extension seemed not to be involved in halotolerance. The remarkable halotolerance may be attributed to the uneven distribution of electrostatic potential and the localized negative charge on the hmCA surface. hmCA displayed similar to 29-fold longer half-life than that of bCA at 40 degrees C in potassium carbonate as a practical absorbent, suggesting that halotolerance should be considered another key characteristic in the development of biocatalysts for CO2 capture using high-salt-containing CO2 absorbents.11Nsciescopu
Bioinspired Load-Bearing Hydrogel Based on Engineered Sea Anemone Skin-Derived Collagen-Like Protein
No full textWith the help of recombinant DNA technology, many protein candidates have been investigated and engineered for biomaterial applications. Particularly, several repeat sequences with unique secondary structures have been selected as minimal building blocks for biosynthesis to improve the mechanical properties of biomaterials. However, most of these structural proteins have been limited to silk, elastin, collagen, and resilin for decades. In the present work, new repeat sequence found in sea anemone are characterized and biosynthesized into a recombinant protein (named anegen) for potential use as a load-bearing biomaterial. Because its repeat sequence unit has a unique polyproline II structure, which is prevalently found in the triple-helix of collagen, it is assumed to be a promising structural protein candidate that can provide conformational flexibility and elasticity. Because anegen has approximate to 10% tyrosine residues, inspiration is taken from di-tyrosine crosslinking in the hinge structures of insects, which can be initiated by light activation. It is found that the anegen hydrogel shows higher mechanical properties than a gelatin hydrogel and endures a compression series without deformation. Moreover, the mechanical properties of the anegen hydrogel are controllable through different crosslinking conditions in a wide range of material applications. Importantly, the anegen hydrogel exhibited suitable cell retainability and cell morphology as an implantable biomaterial. Thus, based on its mechanical properties and biocompatibility, the anegen hydrogel can be used as a potential load-bearing and cell-loading scaffolding biomaterial in the tissue and biomedical engineering fields.11Nsciescopu
Optimization of DNA microarray biosensors enables rapid and sensitive detection
No full textDNA microarray biosensors are essential tools for analyzing transcriptome expression levels and single nucleotide polymorphisms in disease pathology and diagnostics. Since rapid and quantitative detection is necessary for these applications, optimization of the experimental conditions is essential. Here, experimental conditions for DNA microarray biosensors were optimized using an artificial target strategy without reaction or purification bias. Most importantly, hybridization time was reduced to one hour for rapid and homogeneous detection of target DNA. High and low concentrations of capture probe are appropriate for optimizing the limit of detection and dynamic range, respectively. Bleaching effects can be minimized by measuring fluorescence intensity at night. These conditions enable quantitative and precise detection of target DNA and offer experimental guidelines for genobiosensors in general.112sciescopuskc
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