Takeshi Serizawa

Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) were synthesized by anionic polymerization in toluene at −78 °C with t-C4H9MgBr and t-C4H9Li/(C2H5)3Al, respectively, as initiators. Polymers were assembled by the stepwise immersion of a 9-MHz quartz-crystal microbalance (QCM) as a substrate into organic solutions at ambient temperature. Quantitative QCM analysis revealed that acetonitrile was the best solvent for assembly on the substrate compared to acetone and N,N-dime

The layer-by-layer assembly between cationic chitosan and anionic dextran sulfate was analyzed quantitatively by a quartz crystal microbalance technique in the absence and presence of 0.2, 0.5, and 1 M NaCl in the polymer solution. The apparent film thickness increased upon increasing the NaCl concentration. The anti- versus procoagulant activity of these films against whole human blood was studied by the immersion of a substrate into blood for 30 min incubation time at 37 degrees C. The substra

Mechanisms involved in altering left ventricular (LV) diastolic properties during angina were studied in 10 chloralose-anesthetized dogs with chest and pericardium open.Proximal coronary artery stenoses of >90% were created in both left anterior descending and circumflex coronary arteries to abolish reactive hyperemia, and the heart was paced at nearly twice its resting rate (115 ± 4 to 200 ± 5 beats/min).After pacing, increases occurred in LV end-diastolic pressure (EDP, 10 ± 2 to 21 ± 2 mm Hg,

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAlternating Bioactivity of Polymeric Layer-by-Layer Assemblies: Anti- vs Procoagulation of Human Blood on Chitosan and Dextran Sulfate LayersTakeshi Serizawa, Miyuki Yamaguchi, Takahisa Matsuyama, and Mitsuru AkashiView Author Information Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan Cite this: Biomacromolecules 2000, 1, 3, 306–309Publication Dat

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTEnzymatic Hydrolysis of a Layer-by-Layer Assembly Prepared from Chitosan and Dextran SulfateTakeshi Serizawa, Miyuki Yamaguchi, and Mitsuru AkashiView Author Information Department of Nanostructured and Advanced Materials, Graduate School of Science and Engineering, Kagoshima University, Korimoto 1-21-40, Kagoshima 890-0065, Japan Cite this: Macromolecules 2002, 35, 23, 8656–8658Publication Date (Web):October

Thermoresponsive ultrathin hydrogels were prepared by the sequential chemical reaction of poly(vinylamine-co-N-vinylisobutyramide) [poly(VAm-co-NVIBA)] and poly(acrylic acid) (polyAAc) on a gold surface. The carboxyl group of polyAAc was activated by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) for the reaction with the amino group of poly(VAm-co-NVIBA) to yield the amide linkage. This stepwise assembly was analyzed quantitatively by a quartz crystal microbalance (QCM), wh

We studied the adsorption of polystyrene nanospheres that have anionic charges on their surfaces from their aqueous dispersions onto the surfaces of cationic ultrathin polymer films quantitatively and kinetically by using a quartz crystal microbalance (QCM) and scanning electron microscopy (SEM). The polymer films were successively prepared by the alternate adsorption of poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS) in the absence or presence of suitable NaCl con

Poly(vinyl alcohol) (PVA) and poly(methyl methacrylate) (PMMA) were assembled from NaCl-containing aqueous and organic solutions, respectively, by their stepwise physical adsorption onto a quartz crystal microbalance (QCM) substrate, which enabled the quantitative analysis of the assembly process. The layer-by-layer (LbL) assembly was demonstrated by a frequency shift in the QCM, as well as by an analysis of the static contact angles. A reflection absorption spectrum of the LbL assembly revealed

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 pol

Enantiomeric poly(lactide)s were assembled on a quartz crystal microbalance (QCM) substrate, which detects the mass of the polymers from the frequency shift, following immersion of QCM into alternating acetonitrile solutions. A quantitative QCM analysis at each step and a differential scanning calorimetric study of the assembly showed racemic crystal (stereocomplex) formation on the substrate surface. Atomic force microscopic observation showed a dotted nanostructure of the assembly. The assembl

Since graphene is a type of 2D carbon material with excellent mechanical, electrical, thermal, and optical properties, the efficient preparation of graphene macroscopic assemblies is significant in the potentially large-scale application of graphene sheets. Conventional preparation methods of graphene macroscopic assemblies need strict conditions, and, once formed, the assemblies cannot be edited, reshaped, or recycled. Herein, inspired by the biomineralization process, a feasible approach of sh

Ultrathin poly(vinyl alcohol) (PVA) films were fabricated on a gold substrate by a repetitive process based on physical adsorption from aqueous solution in the presence of NaCl and subsequent drying. A quartz crystal microbalance (QCM) was used to analyze the assembled amount quantitatively. The assembled amount increased with increasing NaCl concentration and solution temperature, indicating the adsorption possibly occurred due to the hydrophobic effect. Reflection absorption spectroscopy (RAS)

Degrading films: Surface-component-dependent and time-controlled degradation of a layer-by-layer (LbL) assembly comprising DNA and a cationic synthetic polymer is demonstrated through enzymatic hydrolysis by DNase I (see picture). The negatively charged enzyme is preserved on the cationic polymer surface in an inactive state, and changes in the concentrations of the essential Mg2+ and Ca2+ ions are used to control the activity of the enzyme, and thus control the desorption of the assembly. The f