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Kazuhiko Ishihara - One of the best experts on this subject based on the ideXlab platform.
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blood compatible surfaces with Phosphorylcholine based polymers for cardiovascular medical devices
Langmuir, 2019Co-Authors: Kazuhiko IshiharaAbstract:For the acquisition of blood-compatible materials, various hydrophilic polymers for surface modification have been examined. Among them, polymers with a representative phospholipid polar group, the Phosphorylcholine (PC) group, are a successful example. These polymers were designed from inspiration of the cell membrane surface and provide protein adsorption resistance even following contact with plasma. This important property is based on the unique hydration state of water molecules surrounding hydrated polymer; in other words, water molecules weakly interact with the polymers and maintain their favorable cluster structure through hydrogen bonding. These polymers are not only hydrophilic, but also electrically neutral, important characteristics which make hydrogen bonding with water molecules less likely to occur and avoid hydrophobic interactions. Phosphorylcholine groups and other zwitterionic structures are significant as hydrophilic functional groups meeting these important requirements. In this revi...
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the unique hydration state of poly 2 methacryloyloxyethyl Phosphorylcholine
Journal of Biomaterials Science-polymer Edition, 2017Co-Authors: Kazuhiko Ishihara, Tomohiro Konno, Mingwei Mu, Yuuki Inoue, Kyoko FukazawaAbstract:Abstract2-Methacryloyloxyethyl Phosphorylcholine (MPC) is methacrylate bearing a Phosphorylcholine group in the side chain. The Phosphorylcholine group generates several unique properties arising from its zwitterionic structure, consisting of a phosphate anion and a trimethylammonium cation. Despite these charged groups, the total electrical charge of the species is zero because of the formation of an inner salt. The polymerization of MPC proceeds both conventional and living radical polymerizations. And, using these method, the corresponding polymer can be obtained efficiently. The product, poly(MPC), is soluble in aqueous media, even if the ionic strength of the solution is high, such as in the presence of 5.0 mol/L NaCl. The polymer does not show any surface active properties, even when the polymer concentration is greater than 1.0 g/dL. Hydration of poly(MPC) mainly occurs by hydrophobic hydration of the three methyl groups in the trimethylammonium group. Thus, this hydration induces an increase in a ...
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photoreactive polymers bearing a zwitterionic Phosphorylcholine group for surface modification of biomaterials
ACS Applied Materials & Interfaces, 2015Co-Authors: Kyoko Fukazawa, Kazuhiko IshiharaAbstract:Photoreactive polymers bearing zwitterionic Phosphorylcholine and benzophenone groups on the side chain were synthesized and used as surface modification reagents for biomaterials. A photoreactive methacrylate containing the benzophenone group, 3-methacryloyloxy-2-hydroxypropyl-4-oxybenzophenone (MHPBP), was synthesized via a ring-opening and addition reaction between glycidyl methacrylate and 4-hydroxybenzophenone. Then, water-soluble, amphiphilic polymers poly(2-methacryloyloxyethyl Phosphorylcholine (MPC)-co-MHPBP) (PMH) and poly(MPC-co-n-butyl methacrylate-co-MHPBP), with different monomer unit compositions, were synthesized through radical polymerization. Ultraviolet–visible (UV/vis) absorption spectra of these polymer solutions showed that these polymers have maximum absorption peaks at 254 and 289 nm that can be attributed to the benzophenone unit. The intensity of UV adsorption at 289 nm was decreased with increased UV irradiation time, and it was saturated within a few minutes, indicating that th...
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Critical update on 2-methacryloyloxyethyl Phosphorylcholine (MPC) polymer science
Journal of Applied Polymer Science, 2015Co-Authors: Tatsuro Goda, Kazuhiko Ishihara, Yuji MiyaharaAbstract:2-Methacryloyloxyethyl Phosphorylcholine (MPC) is a custom methacrylate with a zwitterionic Phosphorylcholine moiety on the side chain. In the past 25 years, MPC has been used as a building block for a wide range of polymeric biomaterials because of its excellent resistance to nonspecific protein adsorption, cell adhesion, and blood coagulation. Recently, MPC polymers with specific features have been used in bioengineering and nanomedicine. This review focuses on three topics that highlight the latest findings on MPC polymers, that is, specific recognition of C-reactive protein (CRP), cell-membrane-penetration abilities, and lubrication properties. These developments will extend the applications of this biomimetic material from bioinert polymers to biosensing, CRP inhibitors, prodrug carriers, subcellular bioimaging, cell manipulation, and joint replacement. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41766.
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Establishing ultimate biointerfaces covered with Phosphorylcholine groups.
Colloids and Surfaces B: Biointerfaces, 2008Co-Authors: Junji Watanabe, Kazuhiko IshiharaAbstract:The phospholipid molecule is a typical component of the cell membrane. In particular, the Phosphorylcholine polar group is an electrically neutral head group. 2-Methacryloyloxyethyl Phosphorylcholine (MPC) comprising a Phosphorylcholine group side chain was designed with the cell membrane as an inspiration. Versatile polymers comprising MPC could be synthesized, and their specific biofunctions were evaluated. Establishing an ultimate biointerface with multiple functions is important from the viewpoint of biomaterials science. Nonspecific protein adsorption is essential for achieving versatile biomedical applications. Simultaneously, bioconjugation and retention of its biofunction are crucial for a high-performance biointerface. In this review article, a tunable biointerface comprising MPCs was introduced. In particular, the use of nanoparticles and polymer brushes as biointerfaces was described along with the perspective versatility of their biological applications.
Junji Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Establishing ultimate biointerfaces covered with Phosphorylcholine groups.
Colloids and Surfaces B: Biointerfaces, 2008Co-Authors: Junji Watanabe, Kazuhiko IshiharaAbstract:The phospholipid molecule is a typical component of the cell membrane. In particular, the Phosphorylcholine polar group is an electrically neutral head group. 2-Methacryloyloxyethyl Phosphorylcholine (MPC) comprising a Phosphorylcholine group side chain was designed with the cell membrane as an inspiration. Versatile polymers comprising MPC could be synthesized, and their specific biofunctions were evaluated. Establishing an ultimate biointerface with multiple functions is important from the viewpoint of biomaterials science. Nonspecific protein adsorption is essential for achieving versatile biomedical applications. Simultaneously, bioconjugation and retention of its biofunction are crucial for a high-performance biointerface. In this review article, a tunable biointerface comprising MPCs was introduced. In particular, the use of nanoparticles and polymer brushes as biointerfaces was described along with the perspective versatility of their biological applications.
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Establishing ultimate biointerfaces covered with Phosphorylcholine groups
Colloids and Surfaces B: Biointerfaces, 2008Co-Authors: Junji Watanabe, Kazuhiko IshiharaAbstract:The phospholipid molecule is a typical component of the cell membrane. In particular, the Phosphorylcholine polar group is an electrically neutral head group. 2-Methacryloyloxyethyl Phosphorylcholine (MPC) comprising a Phosphorylcholine group side chain was designed with the cell membrane as an inspiration. Versatile polymers comprising MPC could be synthesized, and their specific biofunctions were evaluated. Establishing an ultimate biointerface with multiple functions is important from the viewpoint of biomaterials science. Nonspecific protein adsorption is essential for achieving versatile biomedical applications. Simultaneously, bioconjugation and retention of its biofunction are crucial for a high-performance biointerface. In this review article, a tunable biointerface comprising MPCs was introduced. In particular, the use of nanoparticles and polymer brushes as biointerfaces was described along with the perspective versatility of their biological applications. ?? 2008 Elsevier B.V. All rights reserved.
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Cytocompatible biointerface on poly(lactic acid) by enrichment with Phosphorylcholine groups for cell engineering
Materials Science and Engineering C, 2007Co-Authors: Junji Watanabe, Bj??rn Atthoff, Tim Bowden, J??ns Hilborn, Fredrik Nederberg, Kazuhiko IshiharaAbstract:A tunable biointerface was designed and prepared using a novel biocompatible phospholipid polymer composed of 2-methacryloyloxyethyl Phosphorylcholine (MPC), n-butyl methacrylate, and isomeric poly(lactic acid) macromonomer. The phospholipid polymer was coated on a substrate, and the surface characterization was examined in terms of surface elemental analysis by X-ray photoelectron spectroscopy and dynamic contact angle measurements. The Phosphorylcholine (PC) group in the MPC units was enriched after immersion in a buffer solution following heating above its glass transition temperature. After the enrichment of the Phosphorylcholine group, the surface wettability was significantly improved and the adsorption behavior of serum proteins was investigated. Albumin and ??-globulin hardly adsorbed on the polymer surface as a result of the surface enriched PC group. On the other hand, adsorption of fibrinogen, which is a cell adhesive protein, was maintained at almost the same level as that from the dry surface. As a result the biointerface on the substrate had dual functions, cytocompatibility by a reduction of the general protein adsorption and cell adhesivity based on the adsorption of fibrinogen. The material duality provides for a tunable biointerface and thus an interesting candidate for cell engineering is formed. ?? 2006 Elsevier B.V. All rights reserved.
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conjugation of enzymes on polymer nanoparticles covered with Phosphorylcholine groups
Biomacromolecules, 2004Co-Authors: Tomohiro Konno, Junji Watanabe, Kazuhiko IshiharaAbstract:We investigated the bioconjugation of enzymes on polymer nanoparticles covered with bioinert Phosphorylcholine groups. A water-soluble amphiphilic phospholipid polymer (PMBN) was specially designed for preparation of nanoparticles and conjugation with enzymes on them. The PMBN was prepared by random copolymerization of 2-methacryloyloxyethyl Phosphorylcholine (MPC), n-butyl methacrylate, and p-nitrophenylester bearing methacrylate. The PMBN was used as an emulsifier and a surface modifier to prepare the poly(l-lactic acid) nanoparticles by a solvent evaporation technique in aqueous medium. The nanoparticles covered with Phosphorylcholine groups were stably dispersed in an aqueous solution and a phosphate buffered saline. The diameter and surface ζ-potential of the nanoparticles were ca. 200 nm and −6 mV, respectively. The p-nitrophenyl ester groups, which are active ester units for the amino groups of the protein, were located at the surface of the nanoparticles. Both acetylcholine esterase and choline ox...
Tomohiro Konno - One of the best experts on this subject based on the ideXlab platform.
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the unique hydration state of poly 2 methacryloyloxyethyl Phosphorylcholine
Journal of Biomaterials Science-polymer Edition, 2017Co-Authors: Kazuhiko Ishihara, Tomohiro Konno, Mingwei Mu, Yuuki Inoue, Kyoko FukazawaAbstract:Abstract2-Methacryloyloxyethyl Phosphorylcholine (MPC) is methacrylate bearing a Phosphorylcholine group in the side chain. The Phosphorylcholine group generates several unique properties arising from its zwitterionic structure, consisting of a phosphate anion and a trimethylammonium cation. Despite these charged groups, the total electrical charge of the species is zero because of the formation of an inner salt. The polymerization of MPC proceeds both conventional and living radical polymerizations. And, using these method, the corresponding polymer can be obtained efficiently. The product, poly(MPC), is soluble in aqueous media, even if the ionic strength of the solution is high, such as in the presence of 5.0 mol/L NaCl. The polymer does not show any surface active properties, even when the polymer concentration is greater than 1.0 g/dL. Hydration of poly(MPC) mainly occurs by hydrophobic hydration of the three methyl groups in the trimethylammonium group. Thus, this hydration induces an increase in a ...
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polymer nanoparticles covered with Phosphorylcholine groups and immobilized with antibody for high affinity separation of proteins
Biomacromolecules, 2008Co-Authors: Yusuke Goto, Madoka Takai, Ryosuke Matsuno, Tomohiro Konno, Kazuhiko IshiharaAbstract:Novel polymer nanoparticles were prepared for the selective capture of a specific protein from a mixture with high effectiveness. The nanoparticle surface was covered with hydrophilic Phosphorylcholine groups and active ester groups for easy immobilization of antibodies. Phospholipid polymers (PMBN) composed of 2-methacryloyloxyethyl Phosphorylcholine, n-butyl methacrylate, and p-nitrophenyloxycarbonyl polyethyleneglycol methacrylate, were synthesized for the surface modification of poly(l-lactic acid) nanoparticles. Surface analysis of the nanoparticles using laser-Doppler electrophoresis and X-ray photoelectron spectroscopy revealed that the surface of nanoparticles was covered with PMBN. Protein adsorption was evaluated with regard to the nonspecific adsorption on the nanoparticles that was effectively suppressed by the Phosphorylcholine groups. The immobilization of antibodies on nanoparticles was carried out under physiological conditions to ensure specific binding of antigens. The antibody immobiliz...
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conjugation of enzymes on polymer nanoparticles covered with Phosphorylcholine groups
Biomacromolecules, 2004Co-Authors: Tomohiro Konno, Junji Watanabe, Kazuhiko IshiharaAbstract:We investigated the bioconjugation of enzymes on polymer nanoparticles covered with bioinert Phosphorylcholine groups. A water-soluble amphiphilic phospholipid polymer (PMBN) was specially designed for preparation of nanoparticles and conjugation with enzymes on them. The PMBN was prepared by random copolymerization of 2-methacryloyloxyethyl Phosphorylcholine (MPC), n-butyl methacrylate, and p-nitrophenylester bearing methacrylate. The PMBN was used as an emulsifier and a surface modifier to prepare the poly(l-lactic acid) nanoparticles by a solvent evaporation technique in aqueous medium. The nanoparticles covered with Phosphorylcholine groups were stably dispersed in an aqueous solution and a phosphate buffered saline. The diameter and surface ζ-potential of the nanoparticles were ca. 200 nm and −6 mV, respectively. The p-nitrophenyl ester groups, which are active ester units for the amino groups of the protein, were located at the surface of the nanoparticles. Both acetylcholine esterase and choline ox...
Jongwon Park - One of the best experts on this subject based on the ideXlab platform.
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antibody immobilization to phospholipid polymer layer on gold substrate of quartz crystal microbalance immunosensor
Colloids and Surfaces B: Biointerfaces, 2007Co-Authors: Madoka Takai, Jongwon Park, Shigeru Kurosawa, Kazuhiko IshiharaAbstract:Abstract To modify gold electrode for immunosensor to construct an artificial cell membrane structure, water-soluble amphiphilic phospholipid polymer, poly[2-methacryloyloxyehtyl Phosphorylcholine- co - n -butyl methacrylate- co - p -nitrophenyloxycarbonyl poly(ethylene glycol) methacrylate (PMBN)] was applied. The polymer had active ester groups for immobilization of biomolecules and it was converted partially to thiol groups for binding to gold substrates. The partially thiolated PMBN was adsorbed on a gold electrode of quartz crystal microbalance (QCM). Surface characterization of adsorbed PMBN layers was thoroughly investigated with reflectance anisotropy spectroscopy, ellipsometry spectroscopy, dynamic contact angle and X-ray photoelectron spectroscopy measurements. Among several PMBN, having different degree of thiolation, it was concluded that 21.5% thiolated PMBN layer had the most well-ordered Phosphorylcholine groups in its outer surface. The proteins adsorption test revealed that the Phosphorylcholine group on the outer side of PMBN layers, which was substituted their active ester groups by glycine, showed suppress the non-specific adsorption of proteins, such as bovine serum albumin and γ-globulin. Also, through antigen–antibody binding evaluation, the anti-C-reactive protein antibody immobilized on the PMBN surface worked well and it was confirmed that denaturation of the antibody on the PMBN layers was hardly occurred in spite of 60 days storage at 4 °C. The antibody conjugated phospholipid polymer layer with well-ordered Phosphorylcholine group could be outstanding functional membrane for biomedical diagnostic devices without non-specific binding and reduction of immunologic activity of immobilized antibody.
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evaluation of 2 methacryloyloxyethyl Phosphorylcholine polymeric nanoparticle for immunoassay of c reactive protein detection
Analytical Chemistry, 2004Co-Authors: Jongwon Park, Shigeru Kurosawa, And Junji Watanabe, Kazuhiko IshiharaAbstract:To prepare novel 2-methacryloyloxyethyl Phosphorylcholine (MPC)−polymeric nanoparticle (MPC−PNP), water-soluble amphiphilic phospholipid polymer, poly [MPC-co-n-butyl methacrylate (BMA)-co-p-nitrophenyloxycarbonyl poly(ethylene glycol) methacrylate (MEONP) (PMBN)], which has active ester groups for bioconjugation on the side chains, was synthesized. MPC−PNP was prepared by a solvent evaporation technique where the poly(l-lactic acid) was used as core and PMBN was applied as an emulsifier and a surface modifier under systematical design of well-arranged phospholipids polar groups in its surface. Characteristics for MPC−PNP were thoroughly investigated with dynamic light scattering, electrophoresis light scattering, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy measurements. Through a protein adsorption test, the Phosphorylcholine group on the surface of MPC−PNPs, which had their active ester groups substituted by glycine, were shown to suppress the nonspecific adsorption...
Nobuo Nakabayashi - One of the best experts on this subject based on the ideXlab platform.
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polymeric lipid nanosphere consisting of water soluble poly 2 methacryloyloxyethyl Phosphorylcholine co n butyl methacrylate
Polymer Journal, 1999Co-Authors: Kazuhiko Ishihara, Yasuhiko Iwasaki, Nobuo NakabayashiAbstract:Polymeric Lipid Nanosphere Consisting of Water-Soluble Poly(2-methacryloyloxyethyl Phosphorylcholine- co - n -butyl methacrylate)
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modification of polysulfone with phospholipid polymer for improvement of the blood compatibility part 1 surface characterization
Biomaterials, 1999Co-Authors: Kazuhiko Ishihara, Yasuhiko Iwasaki, Kikuko Fukumoto, Nobuo NakabayashiAbstract:To improve the surface blood compatibility of polysulfone (PSf) membranes, we prepared novel polymeric additives which have suitable blood compatibility. They were polymers with a Phosphorylcholine group, a 2-methacryloyloxyethyl Phosphorylcholine (MPC) unit. The MPC polymer could be blended with polysulfone by a solvent evaporation method during membrane processing, and a transparent membrane could be obtained. The mechanical properties of the blend membrane were similar to that of the original PSf membrane. Surface analysis of the blend membrane by X-ray photoelectron spectroscopy and dynamic contact angle measurement revealed that the MPC unit in the polymeric additive was concentrated on the surface of the membrane. The blend membrane significantly reduced plasma protein adsorption compared with that of the PSf membrane.
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Interaction between phospholipids and biocompatible polymers containing a Phosphorylcholine moiety
Biomaterials, 1991Co-Authors: Kojima M, Kazuhiko Ishihara, Akihiko Watanabe, Nobuo NakabayashiAbstract:Abstract Random and block copolymers containing a phospholipid polar group in their side chain were synthesized by the copolymerization between 2-methacryloyloxyethyl Phosphorylcholine and styrene. These copolymers showed amphiphilic character, especially poly(methacryloyloxyethyl Phosphorylcholine-block-styrene) formed stable polymer micelles in water. The interaction between natural phospholipid, dipalmitoylphosphatidylcholine and methacryloyloxyethyl Phosphorylcholine copolymers was investigated. The amount adsorbed of dipalmitoylphosphatidylcholine from its liposomal solution on to the poly(methacryloyloxyethyl Phosphorylcholine-co-styrene) surface increased with increase of methacryloyloxyethyl Phosphorylcholine composition. Moreover, when poly(methacryloyloxyethyl Phosphorylcholineblock-styrene) was added to dipalmitoylphosphatidylcholine solution, organization of dipalmitoylphosphatidylcholine molecules and stabilization of bilayer structure of dipalmitoylphosphatidylcholine liposome were found. This means that methacryloyloxyethyl Phosphorylcholine moieties in the copolymer have a strong affinity to dipalmitoylphosphatidylcholine molecules. The blood compatibility of methacryloyloxyethyl Phosphorylcholine copolymers was also investigated with particular attention to the aggregation ability of platelets after contacting methacryloyloxyethyl Phosphorylcholine copolymers; this ability decreased when platelets were put in contact with polymers without a methacryloyloxyethyl Phosphorylcholine moiety. On the other hand, aggregation ability remained at almost the same level to that of original platelets after contact with methacryloyloxyethyl Phosphorylcholine copolymers. From these findings, we concluded that methacryloyloxyethyl Phosphorylcholine copolymers show excellent blood compatibility due to adsorption of lipids from plasma and the formation of an organized adsorption layer of lipids on the surface of the methacryloyloxyethyl Phosphorylcholine copolymers.