Biocompatibility: bioengineering aspects.

Bioengineers have contributed to biocompatibility research. Many materials have been designed, synthesized and characterized by use of various analytical instruments. The blood compatibility of materials has been studied by focusing on the blood-material interfacial reactions.

Application of magnetic field for biological response modification.

The study of magnetic effects on biological system was started in response to Dr. Nose's wish for the development of extracorporeal immunomodulation therapy. In the extracorporeal immunomodulation system, monocytes or lymphocytes in blood are stimulated by the interactions with immune-active materials.

A magnetic fluid seal for rotary blood pumps: effects of seal structure on long-term performance in liquid.

A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids. We developed an MF seal that has a "shield" mechanism, and a new MF with a higher magnetization of 47.

Sealing performance of a magnetic fluid seal for rotary blood pumps.

A magnetic fluid (MF) for a rotary blood pump seal enables mechanical contact-free rotation of the shaft and, hence, has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a "shield" mechanism and a new MF with a higher magnetization of 47.

Characterization of alkali-treated collagen gels prepared by different crosslinkers.

We have developed a naturally-derived crosslinker named malic acid derivative (MAD). In the present study, we prepared alkali-treated collagen (AlCol) gels with different crosslinkers including MAD and commercially available crosslinkers such as 1-ethyl-3-(3('-dimethylaminopropyl) carbodiimide (EDC) and glutaraldehyde (GA). There are named as AlCol-MAD, AlCol-EDC, and AlCol-GA.

Unusual cell adhesion and antithrombogenic behavior of citric acid-cross-linked collagen matrices.

We have developed a novel biodegradable matrix that has unusual cell adhesion and antithrombogenic properties. The prepared biodegradable matrix was alkali-treated collagen (AlCol) cross-linked with citric acid derivative (CAD), named as AlCol-CAD. The swelling ratio of AlCol-CAD decreased with increasing CAD concentration, but with a further increase of the CAD concentration, the swelling ratio of AlCol-CAD also began to increase; this behavior showed a point where the swelling ratio reached a minimum value before increasing.

pH-responsive swelling behavior of collagen gels prepared by novel crosslinkers based on naturally derived di- or tricarboxylic acids.

The aim of this study was to compare the physicochemical properties of alkali-treated collagen (AlCol) gels prepared using two kinds of naturally derived crosslinkers made from citric and malic acids (CAD and MAD, respectively) that we have developed. From the crosslinking reaction between active ester groups and amino groups of AlCol, we successfully obtained AlCol gels, named AlCol-CAD and AlCol-MAD, prepared using CAD and MAD, respectively. The gelation time of the AlCol solution containing CAD initially decreased with increasing CAD concentration up to 70 mM, and then increased as the CAD concentration increased further.

The Japanese artificial organs scene: current status.

Artificial organs and regenerative medicine are the subjects of very active research and development (R&D) in Japan and various artificial organs are widely used in patients. Results of the R&D are presented at the annual conference of the Japanese Society for Artificial Organs (JSAO). Progress in the fields of artificial organs and regenerative medicine are reviewed annually in the Japanese Journal of Artificial Organs.

An estimation method of hemolysis within an axial flow blood pump by computational fluid dynamics analysis.

Evaluation of hemolysis within a blood pump on a computer is useful for developing rotary blood pumps. The flow fields in the axial flow blood pump were analyzed using computational fluid dynamics (CFD). A blood damage index was calculated based on the changes in shear stress with time along 937 streamlines.

Development of a magnetic fluid shaft seal for an axial-flow blood pump.

A rotating impeller in a rotary blood pump requires a supporting system in blood, such as a pivot bearing or magnetic suspension. To solve potential problems such as abrasive wear and complexity of a supporting system, a magnetic fluid seal was developed for use in an axial-flow blood pump. Sealing pressures at motor speeds of up to 8,000 rpm were measured with the seal immersed in water or bovine blood.

In vitro evaluation of newly developed adsorbent for selective removal of glycosylated low-density lipoprotein.

Chronic hyperglycemia leads to the accumulation of nonenzymatically derived glycosylation products on proteins. Such glycosylation products, especially glycosylated low-density lipoprotein (glc-LDL), have been increasingly recognized as factors in the pathogeneses of diabetic complications. A new adsorbent was developed for the selective removal of glc-LDL from plasma.