Published papers

Poly(N‐isopropylacrylamide) (PNIPAM) hydrogel microspheres were prepared by precipitation polymerization above the polymer's lower critical solution temperature (LCST) in water. The hydrodynamic size of PNIPAM microspheres exhibited a thermo‐sensitive change around the LCST. In order to obtain information about the interface of the hydrogels, contact angle measurement, protein adsorption, and fluorescence analysis were performed. Contact angle measurement and protein adsorption showed a gradual change around the LCST similar to the change of the hydrodynamic size. However, fluorescence study exhibited a sharp change at the LCST. In addition, a quenching experiment was employed to elucidate the location of the fluorescent probes. In the PNIPAM latex, the probes were located where they were less quenchable as compared to the PNIPAM solution. It seems probable that the probes can penetrate into the crosslinked PNIPAM hydrogel and might reflect the inner environment of the hydrogel. The effect of salt on thermo‐sensitive behaviour was also detected by fluorescence analysis. On the other hand, the hydrogel microsphere prepared from poly(acryloyl pyrrolidine) (PAPr) showed a gradual change in fluorescence with temperature. Copyright © 1993 Society of Chemical Industry

A tetrapeptide RGDS (Arg-Gly-Asp-Ser), which is one of the active sites of cell adhesive proteins, was synthesized according to the solution method and covalently coupled onto monodisperse microspheres. The biospecific activity of the RGDS-carrying microspheres was investigated by measuring the stimulatory effect of the microspheres on platelets. Large and tightly packed platelet aggregation accompanied with drastic ATP release was induced by the RGDS-carrying microspheres. It was confirmed that the specific platelet aggregation was attributed to the activity of the immobilized RGDS by comparison with those induced by other microspheres. © 1993, VSP. All rights reserved.

Precipitation polymerization of N-isopropylacrylamide (NIPAM) with methylenebisacrylamide (MBAAm) in water at 70°C gave thermosensitive hydrogel microspheres. The adsorbability of proteins on the poly-NIPAM microspheres was found to depend on temperature. Below the lower critical solution temperature (LCST) of poly-NIPAM in an aqueous medium, that is, around 32°C, the microspheres hold a large amount of water inside and their surface is hydrophilic enough to suppress the adsorption of proteins. On the contrary, above 32°C, the micropheres deswell and their surface becomes hydrophobic and, consequently, susceptible to adsorption of a large amount of proteins. Proteins once adsorbed on the microspheres at a high temperature could be desorbed more or less by lowering the temperature to below 32°C. The extent of desorption at low temperatures was found to depend on the incubation time for adsorption at high temperatures.

ポリウレタンからなる人工血管を用いて埋植実験を行い、その機械的性質が重要である結果を得た。

This paper describes the results of plasma- and ozone-induced graft polymerization of acrylamides, together with the amount of peroxides formed by the plasma treatment and the ozonization. It is concluded that both the treatments of polymer surfaces by plasma and ozone produce polymeric peroxides which are capable of initiating graft polymerization, even if the treatments are conducted under a mild condition. An advantage of the ozonization over the plasma treatment is easy and uniform introduction of peroxides on the surface of molded products even with complicated shapes.

The purpose of this work is to modify PU by surface graft polymerization of acrylic monomers so as to reduce protein adsorption and platelet adhesion. It is shown that there is an optimum in the graft amount which leads to the minimum protein adsorption and thrombus formation.

全身的な抗凝血剤処置を行わずに肝臓移植を行うための、新規の静脈-静脈バイパス技術を開発した。

特定の脂質は細胞にアポトーシスを誘導した。これらの脂質は培養液中でサブミクロンサイズのエマルションを形成して細胞膜に分配することがわかった。さらにこの分配に際して細胞膜の動的な変化が極めて短時間で起こり、アポトーシス発現のマーカーとなることがわかった。