• Title/Summary/Keyword: K-based hydrogel

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Selective Response of Dye Rotaxane to Metal Ions (금속 이온에 대한 염료 로택산의 선택적 반응성)

  • Park, Jong-S.
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 2011.03a
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    • pp.35-35
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    • 2011
  • The design and preparation of novel dye rotaxanes have gained much interest recently, since such structure usually exhibits peculiar spectral and optical changes. In spite of the promising results to date, increasing pressure remains to develop novel supramolecular structures based on stimuli-responsive systems. This presentation covers the study of inclusion complexes of cyclodextrins and various chromophores, with an emphasis on our most recent outcome of anisotropic hydrogel. In this system, physical gelation prepared from simple mixture of CD and a azo dye is completed through specific host-guest interaction. The obtained hydrogel exhibits respective morphological transitions based on supramolecular assembly and dissociation, leading to either precipitation or a sol-to-gel transition. It can identify different classes of metal ions, and, among them, naked-eye differentiation of lead ion is possible due to the coordination-induced unthreading of dye molecules. Accompanying structural changes were verified by numerous characterization techniques, including 2D-ROESY, HR-MAS, UV-Visible absorption, small-angle X-ray scattering, and induced circular dichroism measurements. Such properties discussed here will find useful in analytical applications, such as metal ion sensing and removal applications.

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Highly Stretchable, Transparent Ionic Touch Panel

  • Sun, Jeong-Yun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.51-63
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    • 2017
  • The touch panel was developed decades ago and has become a popular input device in daily life. Because human-computer interaction is becoming more important, the next generation of touch panels require stretchability and bio-compatibility to allow integration with the human body. However, because most touch panels were developed based on stiff, brittle electrodes, electronic touch panels face difficulties to achieve such requirements. In this paper, for the first time, we demonstrate an ionic touch panel based on polyacrylamide hydrogel containing LiCl ions. The panel is soft and stretchable and thus, can sustain a large deformation. The panel can freely transmit light information through it because the hydrogel is transparent, with 99 % transmittance for visible light. A 1-dimensional touch strip was investigated to reveal the basic mechanism of sensing, and a 2-dimensional touch panel was developed to demonstrate its functionalities. The ionic touch panel was operated under high deformation with more than 1000% areal strain without sacrificing its functionalities. Furthermore, an epidermal touch panel on the skin was developed to demonstrate the mechanical and optical invisibility of the ionic touch panel through writing words, playing the piano and playing games.

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Bone Formation Effect of the RGD-bioconjugated Mussel Adhesive Proteins Composite Hydroxypropyl Methylcellulose Hydrogel Based Nano Hydroxyapatite and Collagen Membrane in Rabbits

  • Kim, Dong-Myong;Kim, Hyun-Cho;Yeun, Chang-Ho;Lee, Che-Hyun;Lee, Un-Yun;Lim, Hun-Yu;Chang, Young-An;Kim, Young-Dae;Choi, Sung-Ju;Lee, Chong-Suk;Cha, Hyung Joon
    • Journal of Marine Bioscience and Biotechnology
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    • v.7 no.2
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    • pp.58-70
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    • 2015
  • Injectable RGD-bioconjugated Mussel Adhesive Proteins (RGD-MAPs) composite hydroxypropyl methylcellulose (HPMC) hydrogels provide local periodontal tissue for bone filling in periodontal surgery. Previously we developed a novel type of injectable self-supported hydrogel (2 mg/ml of RGD-MAPs/HPMC) based porcine nano hydroxyapatite (MPH) for dental graft, which could good handling property, biodegradation or biocompatibility with the hydrogel disassembly and provided efficient cell adhesion activity and no inflammatory responses. Herein, the aim of this work was to evaluate bone formation following implantation of MPH and collagen membrane in rabbit calvarial defects. Eight male New Zealand rabbits were used and four circular calvarial defects were created on each animal. Defects were filled with different graft materials: 1) collagen membrane, 2) collagen membrane with MPH, 3) collagen membrane with bovine bone hydroxyapatite (BBH), and 4) control. The animals were sacrificed after 2 and 8 weeks of healing periods for histologic analysis. Both sites receiving MPH and BBH showed statistically increased augmented volume and new bone formation (p < 0.05). However, there was no statistical difference in new bone formation between the MPH, BBH and collagen membrane group at all healing periods. Within the limits of this study, collagen membrane with MPH was an effective material for bone formation and space maintaining in rabbit calvarial defects.

Induction of Angiogenesis by Matrigel Coating of VEGF-Loaded PEG/PCL-Based Hydrogel Scaffolds for hBMSC Transplantation

  • Jung, Yeon Joo;Kim, Kyung-Chul;Heo, Jun-Young;Jing, Kaipeng;Lee, Kyung Eun;Hwang, Jun Seok;Lim, Kyu;Jo, Deog-Yeon;Ahn, Jae Pyoung;Kim, Jin-Man;Huh, Kang Moo;Park, Jong-Il
    • Molecules and Cells
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    • v.38 no.7
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    • pp.663-668
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    • 2015
  • hBMSCs are multipotent cells that are useful for tissue regeneration to treat degenerative diseases and others for their differentiation ability into chondrocytes, osteoblasts, adipocytes, hepatocytes and neuronal cells. In this study, biodegradable elastic hydrogels consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(${\varepsilon}$-caprolactone) (PCL) scaffolds were evaluated for tissue engineering because of its biocompatibility and the ability to control the release of bioactive peptides. The primary cultured cells from human bone marrow are confirmed as hBMSC by immunohistochemical analysis. Mesenchymal stem cell markers (collagen type I, fibronectin, CD54, $integrin1{\beta}$, and Hu protein) were shown to be positive, while hematopoietic stem cell markers (CD14 and CD45) were shown to be negative. Three different hydrogel scaffolds with different block compositions (PEG:PCL=6:14 and 14:6 by weight) were fabricated using the salt leaching method. The hBMSCs were expanded, seeded on the scaffolds, and cultured up to 8 days under static conditions in Iscove's Modified Dulbecco's Media (IMDM). The growth of MSCs cultured on the hydrogel with PEG/PCL= 6/14 was faster than that of the others. In addition, the morphology of MSCs seemed to be normal and no cytotoxicity was found. The coating of the vascular endothelial growth factor (VEGF) containing scaffold with Matrigel slowed down the release of VEGF in vitro and promoted the angiogenesis when transplanted into BALB/c nude mice. These results suggest that hBMSCs can be supported by a biode gradable hydrogel scaffold for effective cell growth, and enhance the angiogenesis by Matrigel coating.

Preparation and Characterization of Poly(vinyl alcohol)/Poly(acrylic acid) Hydrogel by Radiation (방사선을 이용하여 제조한 poly(vinyl alcohol)/poly(acrylic acid) 하이드로젤의 제조 및 특성)

  • Park, Jong-Seok;Kim, Hyun-A;Choi, Jong-Bae;Gwon, Hui-Jeong;Lim, Youn-Mook;Nho, Young-Chang
    • Journal of Radiation Industry
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    • v.5 no.4
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    • pp.377-382
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    • 2011
  • Poly(vinyl alcohol) (PVA) is an interesting material with good biocompatibility, high elasticity and hydrophilic chacrateristics. In this study, crosslinked hydrogels based on PVA, and poly(acrylic acid) (PAAc) were prepared by gamma-ray irradiation. PVA and PAAc powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make hydrogels. The hydrogels were then annealed in an oven at $120^{\circ}C$ for 10 min, 30 min and 50 min under nitrogen atmosphere. The properties of a hydrogel such as gel fraction, swelling behavior, thermogravimetric analysis (TGA) and adhesive strength as a function of PAAc content and annealing time were investigated. The gel fraction decreases with decreasing PAAc content and increasing annealing time. The thermal behaviors have shown different patterns according to the annealing time. The adhesive strength increases with increasing PAAc content.

pH-Dependent Drug Release from Polymethacrylic Acid Hydrogel Matrix (Polymethacrylic Acid 하이드로겔 매트릭스로부터의 pH 의존성 약물 방출)

  • Kim, Kyung-Chung;Kim, Kil-Soo;Lee, Seung-Jin
    • Journal of Pharmaceutical Investigation
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    • v.19 no.4
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    • pp.179-183
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    • 1989
  • Drug release experiments were performed based on pH-sensitive swelling behaviors of polymethacrylic acid. 5-Fluorouracil as a nonionic model drug revealed release patterns depending solely on pH-dependent swelling kinetics of polymethacrylic acid. In contrast, release of propranolol hydrochloride as a cationic model drug was significantly affected by ionic drug-polymer interaction as well as the swelling kinetics. Accordingly, a zero-order release pattern was obtained at pH 7, which was distinguished from the general matrix type drug release pattern.

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Physicochemical Characteristics of Fe3O4 Magnetic Nanocomposites Based on Poly(N-isopropylacrylamide) for Anti-cancer Drug Delivery

  • Davaran, Soodabeh;Alimirzalu, Samira;Nejati-Koshki, Kazem;Nasrabadi, Hamid Tayefi;Akbarzadeh, Abolfazl;Khandaghi, Amir Ahmad;Abbasian, Mojtaba;Alimohammadi, Somayeh
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.1
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    • pp.49-54
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    • 2014
  • Background: Hydrogels are a class of polymers that can absorb water or biological fluids and swell to several times their dry volume, dependent on changes in the external environment. In recent years, hydrogels and hydrogel nanocomposites have found a variety of biomedical applications, including drug delivery and cancer treatment. The incorporation of nanoparticulates into a hydrogel matrix can result in unique material characteristics such as enhanced mechanical properties, swelling response, and capability of remote controlled actuation. Materials and Methods: In this work, synthesis of hydrogel nanocomposites containing magnetic nanoparticles are studied. At first, magnetic nanoparticles ($Fe_3O_4$) with an average size 10 nm were prepared. At second approach, thermo and pH-sensitive poly (N-isopropylacrylamide -co-methacrylic acid-co-vinyl pyrrolidone) (NIPAAm-MAA-VP) were prepared. Swelling behavior of co-polymer was studied in buffer solutions with different pH values (pH=5.8, pH=7.4) at $37^{\circ}C$. Magnetic iron oxide nanoparticles ($Fe_3O_4$) and doxorubicin were incorporated into copolymer and drug loading was studied. The release of drug, carried out at different pH and temperatures. Finally, chemical composition, magnetic properties and morphology of doxorubicin-loaded magnetic hydrogel nanocomposites were analyzed by FT- IR, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM). Results: The results indicated that drug loading efficiency was increased by increasing the drug ratio to polymer. Doxorubicin was released more at $40^{\circ}C$ and in acidic pH compared to that $37^{\circ}C$ and basic pH. Conclusions: This study suggested that the poly (NIPAAm-MAA-VP) magnetic hydrogel nanocomposite could be an effective carrier for targeting drug delivery systems of anti-cancer drugs due to its temperature sensitive properties.

Preparation and Characterization of Hydrogels containing Silicone or Fluorine

  • Kim, Eui Seok;Shim, Sang-Yeon
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.3
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    • pp.650-656
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    • 2017
  • The water-swollen hydrogels containing silicone or fluorine were prepared by copolymerization of 2-hydroxy ethyl methacylate (HEMA) with 3-(trimethoxysilyl)propyl methacrylate(SM) or 2,2,2-trifluoroethyl acrylate(FA). When the content of SM or FA increased in copolymers, there was tendency of water absorbance to decrease, whereas contact angles to increase. The hydrogels containing FA showed 2 ~ 4% higher water content and 4 ~ 5% lower contact angles compared to that of SM. Tensile strengths decreased as the content of SM increased. However, FA exhibited strength of $2.2Mpa/cm^2$ which is similar to $2.3Mpa/cm^2$ of B. FA, which implies comparatively low adherence, hence, showed better protein resistance properties than SM-based hydrogel. The photo-polymerization was also applied instead of thermal polymerization to enhance the energy efficiency. As a result, the reaction yield reached over 95% within 1 minute.

Production optimization of flying fish roe analogs using calcium alginate hydrogel beads

  • Ha, Bom-Bi;Jo, Eun-Hee;Cho, Suengmok;Kim, Seon-Bong
    • Fisheries and Aquatic Sciences
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    • v.19 no.7
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    • pp.30.1-30.7
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    • 2016
  • Due to decreased supplies of marine resources and byproducts, new processing technologies for the development of analogs for natural fishery products are becoming increasingly important in the fishing industry. In the present study, we investigated the optimal processing conditions for flying fish roe analogs based on alginate hydrogels. Optimized processing of these analogs was performed by response surface methodology. The optimal processing conditions for the flying fish roe analogs (based on sphericity) were at a sodium alginate concentration of 2.41 %, calcium chloride solution curing time of 40.65 min, calcium chloride concentration of 1.51 %, and a reactor stir speed of $254{\times}g$. When the experiment was performed under these optimized conditions, the size (mm), sphericity (%), and rupture strength (kPa) of the analogs were $2.2{\pm}0.12$, $98.2{\pm}0.2$, and $762{\pm}24.68$, respectively, indicating physical properties similar to their natural counterparts.