Peptide motifs that recognize differences in polymer-film surfaces.
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Peptide Library↗
Biomedical subjects
Takeshi Serizawa
Publications and source records attributed to Takeshi Serizawa.
Preparation and characterization of stimuli-resistible hydrogels nano-coated with polyelectrolyte multilayer films.
Alginate (ALG) hydrogels were nano-coated with polyelectrolyte multilayer (PEM) films composed of poly(diallyldimethyl ammonium chloride) (PDDA) and poly(sodium 4-styrenesulfonate) (PSS). Non- and nano-coated ALG hydrogels were immersed into salt solutions (pH 6, ionic strength: 0.01 M), and the swelling behavior of these ALG hydrogels was observed by optical microscopy. The increases in the diameter of the 10-step coated ALG hydrogels were one fourth or less than that of the non-coated hydrogels. These results indicate that the characteristics of nano-coated ALG hydrogels remain unchanged independent of how the external environment is changed (e.g., pH, ionic strength). Consequently, tolerant ionic hydrogels may be prepared by the nano-coating of hydrogel surfaces with PEM films and may be useful for technological and biomedical applications.
Absorption↗
A peptide motif recognizing a polymer stereoregularity.
A combinatorial phage display method was applied to films composed of a stereoregular polymer of methacrylates. The phage clones with selective affinity for isotactic (it) poly(methyl methacrylate) (PMMA) were isolated. Greater amounts of the phage clones bound to it-PMMA, compared to other stereoregular PMMAs. The phage expressing ELWRPTR most strongly bound to the polymer, and the selectivity was also the best. The peptide motif essential for the specific interaction with the stereoregular polymer was revealed.
Amino Acid Motifs↗
Loading and release of charged dyes using ultrathin hydrogels.
The anionic dyes methyl orange (MO) and allura red (AR) were used as model drugs to assess the loading and release by layer-by-layer assembled ultrathin hydrogels prepared via the amide formation of poly(acrylic acid-co-N-isopropylacrylamide) with AAc contents of 5, 10, and 15 mol % plus poly(vinylamine hydrochloride). The amount of MO loaded was potentially controlled by changing the dye concentrations, film thickness, and AAc content of the copolymers. The release of AR was controlled by the NaCl concentration and pH. We conclude that the polymeric matrices of ultrathin hydrogels have great potential for the loading and release of charged drugs.
Acrylamides↗
Novel functional biodegradable polymer. III. The construction of poly(gamma-glutamic acid)-sulfonate hydrogel with fibroblast growth factor-2 activity.
Poly(gamma-glutamic acid)-sulfonate (gamma-PGA-S) hydrogel, with fibroblast growth factor (FGF)-2 activity was investigated as a novel, next-generation tissue-engineering material. gamma-PGA-net-gamma-PGA-S72 (S72-netgel) was prepared with gamma-PGA-S and gamma-PGA-S72 (72% sulfonated gamma-PGA) to provide the high mobility of gamma-PGA-S72 for FGF-2 activity. Cell adhesion and proliferation activities were evaluated on gamma-PGA and gamma-PGA-S hydrogels along with S72-netgels. Both cell adhesion and proliferation activities of gamma-PGA and gamma-PGA-S hydrogels were low. In contrast, S72-netgels had high cell adhesion and proliferation activities, because of their low swelling ratios and high sulfonic acid group concentrations. Furthermore, S72-netgels had high FGF-2 activity, because gamma-PGA-S72 retained FGF-2 activity when incorporated into S72-netgels. S72-netgels should be useful as next-generation tissue-engineering material containing FGF-2 activity.
Animals↗
Controlled release based on the dissolution of a calcium carbonate layer deposited on hydrogels.
It is possible that inorganic materials conjugated to suitable organic materials may induce unique mechanical, optical and other functional properties. Therefore, artificial conjugation of organic and inorganic components is attractive for preparing novel functional materials. Recently, we developed an alternate soaking process for calcium salt formation on/in polymer materials. In this study, a poly(vinyl alcohol) (PVA) hydrogel-calcium carbonate (CaCO(3)) composite was prepared by the aforementioned process as a controlled release support. Brilliant blue FCF (Mw = 794), FITC labeled BSA (Mw = 6.6 x 10(4)), FITC labeled dextran-10 k (Mw = 9.5 x 10(3)) and FITC labeled dextran-40 k (Mw = 4.3 x 10(4)) were loaded into the composite as model drugs. CaCO(3) dissolution and model drug release rates increased with a decrease in buffer pH. In addition, model drug release rates increased with a decrease in model drug molecular weight. These results show that CaCO(3) layers on hydrogels behave as capping layers for model drug release; the release rate of model drugs can be controlled by the dissolution rate of CaCO(3) and the molecular weight of the drug.
Calcium Carbonate↗
Polymerization within a molecular-scale stereoregular template.
Enzymes efficiently synthesize biopolymers by organizing monomer units within regularly structured molecular-scale spaces and exploiting weak non-covalent interactions, such as hydrogen bonds, to control the polymerization process. This 'template' approach is both attractive and challenging for synthetic polymer synthesis, where structurally regulated molecular-scale spaces could in principle provide solid-phase reaction sites for precision polymerization. Previously, free-radical polymerization of methyl methacrylate in solutions containing stereoregular isotactic (it) or syndiotactic (st) poly(methyl methacrylate) (PMMA) has been shown to result in template synthesis of the opposite PMMA based on stereocomplex formation with van der Waals interactions. However, using the structure of a solid to determine the stereochemical structure of a polymer has not been satisfactorily achieved. Here we show that macromolecularly porous ultrathin films, fabricated by a single assembly step, can be used for the highly efficient stereoregular template polymerization of methacrylates through stereocomplex formation. This reaction mould accurately transfers its structural properties of stereoregularity, molecular weight and organization within the template to the new polymer.
Journal Article↗
Preparation and thermosensitivity of naturally occurring polypeptide poly(gamma-glutamic acid) derivatives modified by propyl groups.
Poly(gamma-glutamic acid) (gamma-PGA) is a biosynthetic polymer, and the carboxyl groups are able to undergo a chemical modification. In this study, poly(alpha-propyl gamma-glutamate) (gamma-PGA propylate) was synthesized by the esterification of these carboxyl groups to yield a thermosensitive and biodegradable polymer. In aqueous solution, the gamma-PGA propylate can impart thermosensitivity by controlling the hydrophobic-hydrophilic balance of the gamma-PGA polymeric chains.
Drug Stability↗
Induction of HIV-specific antibody response and protection against vaginal SHIV transmission by intranasal immunization with inactivated SHIV-capturing nanospheres in macaques.
We have previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and that intranasal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody response in mice. In this study, to evaluate the protective effect of immunization, each three macaques was intranasally immunized with Con A-NS or inactivated simian/human immunodeficiency virus KU-2-capturing nanospheres (SHIV-NS) and then intravaginally challenged with a pathogenic virus, SHIV KU-2. After a series of six immunizations, vaginal anti-HIV-1 gp120 IgA and IgG antibodies were detected in all SHIV-NS-immunized macaques. After intravaginal challenge, one of the three macaques in each of the Con A-NS- and SHIV-NS-immunized groups was infected. Plasma viral RNA load of infected macaque in SHIV-NS-immunized macaques was substantially less than that in unimmunized control macaque and reached below the detectable level. However, it could not be determined whether intranasal immunization with SHIV-NS is effective in giving complete protection against intravaginal challenge. To explore the effect of the SHIV-NS vaccine, the remaining non-infected macaques were rechallenged intravenously with SHIV KU-2. After intravenous challenge, all macaques became infected. However, SHIV-NS-immunized macaques had lower viral RNA loads and higher CD4(+) T cell counts than unimmunized control macaques. Plasma anti-HIV-1 gp120 IgA and IgG antibodies were induced more rapidly in the SHIV-NS-immunized macaques than in the controls. The rapid antibody responses having neutralizing activity might contribute to the clearance of the challenge virus. Thus, SHIV-NS-immunized macaques exhibited partial protection to vaginal and systemic challenges with SHIV KU-2.
AIDS Vaccines↗
Cell-adhesive and blood-coagulant properties of ultrathin poly(methyl methacrylate) stereocomplex films.
Isotactic (it) and syndiotactic (st) poly(methyl methacrylate)s (PMMAs) were assembled on a poly(ethylene terephthalate) cell disk (as a solid substrate), which is normally used for cell culture, to produce ultrathin stereocomplex films. Static contact angles of the films using air bubbles in aqueous phase revealed the stepwise assembly of both polymers. More L929 fibroblast cells adhered and were flattened on the ultrathin stereocomplex films, compared to homogeneous PMMA films and to spin-coated films comprised of a mixed solution of it- and st-PMMAs with a molar ratio of 1 : 2, which is the stoichiometry of a stereocomplex. The difference in the number of adherent cells was greatest after the first 3 h of incubation. Pre-adsorption of proteins, which are related to cell adhesion, onto the stereocomplex film potentially modulated the cell-adhesive properties. Fresh whole human blood did not coagulate on the complex film for 20 min, although blood coagulated after 15 min on the homogeneous films and on the 1 : 2 mixed film. Platelets did not adhere onto the complex films after 15 min of incubation, which was consistent with the results of blood coagulation. These observations indicate that the stereocomplex formation of PMMAs on the surface of films strongly affects the bioactivity of these films.
Animals↗
Bioinspired organic-inorganic composite materials prepared by an alternate soaking process as a tissue reconstitution matrix.
Poly(acrylic acid) (PAAc) grafted poly(ethylene) (PE) (PAAc-g-PE) film-apatite or calcium carbonate (CaCO3) composite materials were prepared by an alternate soaking process, which simply forms apatite or CaCO3 on the polymer materials by alternate soaking in Ca(2+)- and PO(3-)4- or CO(3)2- -containing solutions. X-ray diffraction analysis of the composite films indicated the presence of hydroxyapatite or CaCO3 on the film. Scanning electron microscopic observation revealed that the whole surface of the film was covered by the apatite or CaCO3. Cell compatibility tests of the apatite- or CaCO3-coated film suggested that the greater number of cells adhered on the films and that the cell proliferation properties were extremely greater on the films.
Animals↗
Alternating gene expression in fibroblasts adhering to multilayers of chitosan and dextran sulfate.
The alternating compatibility of fibroblast cells adhering to multilayers of chitosan and dextran sulfate (Dex) on a substrate was analyzed at the gene expression level. A greater number of round-shaped cells adhered to the films with an outermost surface composed of Dex, although the total number of adherent cells was independent of the film surface. Greater expression of heat-shock protein 70B mRNA was demonstrated in cells adhering to films with the Dex surface. It was found that analysis of gene expression was a powerful tool for evaluating the bioactivity of multilayers.
Biocompatible Materials↗
Osteoconductive and hemostatic properties of apatite formed on/in agarose gel as a bone-grafting material.
The biologic behavior of hydroxyapatite formed on/in agarose (HA/agarose) gels with the use of a novel alternate soaking process was compared with commercially available Bone Ject (True-Bone ceramic-collagen combined bone-graft material, Koken, Japan) as a filler for the tooth-extraction sockets of six adult monkeys (Macasa fascicularis). After the monkeys' first premolars were extracted, the defects created were replaced with one of the following materials: (a). HA/agarose created by 12 soaking cycles, (b). HA/agarose created by 9 soaking cycles, (c). Bone Ject, and (d). no material implantation (control). The time of hemostasis in each extraction site was estimated, and the samples were then studied histologically. In the controls, the time of hemostasis was about 5 min. The Bone Ject particles were easily washed out by bleeding, and the time of hemostasis was about 15 min. The HA/agarose gel was densely packed into the bony defect. The hemorrhage from the defects stopped within a few seconds after graft placement. This hemostasis was most likely related to the compactibility and adhesiveness of the material. After 12 weeks of implantation, free Bone Ject particles surrounded by inflammatory cells were observed. The bony defect filled with the HA/agarose gels was completely absorbed and replaced by newly formed bone possessing bone marrow. There was no difference in the biologic behavior of HA/agarose gels created by 9 versus 12 soaking cycles. The present study suggests that HA/agarose gels may play an important role as an alternative biodegradable bone-graft material for autogenous bone in humans.
Animals↗
Time-controlled desorption of ultrathin polymer films triggered by enzymatic degradation.
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Animals↗
Recognition of stereoregular polymers by using structurally regulated ultrathin polymer films.
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Journal Article↗
Mucosal immunization with inactivated HIV-1-capturing nanospheres induces a significant HIV-1-specific vaginal antibody response in mice.
Mucosal secretory IgA is considered to have an important role in the prevention of human immunodeficiency virus type 1 (HIV-1) transmission through sexual intercourse. Therefore, substances that induce HIV-1-specific IgA antibody in the genital tract may become promising candidates for prophylactic vaccine against HIV-1 infection. We have previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and gp120 antigens on their surface and that intravaginal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody in mice. In this study, various strategies for immunization with HIV-NS were undertaken to induce HIV-1-specific IgA response in the mouse genital tract. HIV-NS were administered intravaginally, orally, intranasally or intraperitoneally to mice. Progesterone treatment enhanced the anti-HIV-1 IgA response to intravaginal immunization significantly, but intranasal immunization with HIV-NS was more effective compared with other immunization routes in terms of vaginal IgA response. In addition, vaginal washes from intranasally immunized mice were capable of neutralizing HIV-1(IIIB). Thus, application of HIV-NS is a practical approach to promote HIV-1-specific IgA response by the vaginal mucosa in the mouse and intranasal appears to be an effective immunization route in this animal model. Intranasal immunization with HIV-NS should be further pursued for its potential as an HIV-1 prophylactic vaccine.
AIDS Vaccines↗
Cell-compatible properties of calcium carbonates and hydroxyapatite deposited on ultrathin poly(vinyl alcohol)-coated polyethylene films.
Poly(vinyl alcohol) (PVA) was coated onto polyethylene (PE) films by a repetitive adsorption and drying process, and then the PVA-coated PE films were alternately immersed into aqueous solutions of Ca2+ and CO3(2-) ions (alternate soaking cycles), to deposit calcium carbonate (CaCO3) onto the films. The PVA coating was essential for the CaCO3 deposition. The amount of CaCO3 deposited increased with an increasing number of cycles. Scanning electron microscopic observations and attenuated total reflection spectra revealed the presence of both calcite and aragonite as the crystal structures of CaCO3 on the film. L929 fibroblast cells adhered and proliferated on these CaCO3-deposited PE films, as well as the hydroxyapatite-coated PE films previously prepared. It was found that the PVA coating and the subsequent deposition of calcium salts on certain films facilitated cell compatibility.
Calcium Carbonate↗
Induction of mucosal IgA following intravaginal administration of inactivated HIV-1-capturing nanospheres in mice.
Concanavalin A-immobilized polystyrene nanospheres (Con A-NS) were developed for the HIV-1 vaccine capable of preventing sexual transmission. Con A-NS could capture efficiently HIV-1 irrespective of their cell tropism (R5 or X4). Furthermore, Con A-NS captured equally infectious and heat-inactivated HIV-1. Inactivated HIV-1-capturing Con A-NS (HIV-NS) were intravaginally administered to mice. Heat-inactivated HIV-1 alone and Con A-NS alone were also administered as control immunogens. Vaginal fluids were collected during and after immunization and analyzed for their anti-HIV-1 antibody levels. Although the anti-HIV-1 IgG antibody was undetectable in any groups, increased anti-HIV-1 IgA antibody response was identified in the vaginal fluids of immunized mice with HIV-NS. The vaginal fluids obtained from the HIV-NS-administered mice showed neutralizing activity against the immunizing HIV-1 strain. A marked difference in vaginal distribution was observed between HIV-NS and other immunogens, and the toxicity of Con A was reduced by conjugation with nanospheres. Thus, HIV-NS may have great potential as a prophylactic HIV-1 vaccine and should be examined further for its efficacy in non-human primates.
Animals↗