Yoshihito Osada

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Various hydrogels without modification by any cell adhesive proteins have been investigated as cell scaffolds. The present study shows that bovine fetal aorta endothelial cells can adhere, spread, proliferate, and reach confluence on poly(acrylic acid), poly(sodium p-styrene sulfonate), and poly(2-acrylamido-2- methyl-1-propanesulfonic sodium) gels, whereas(More)
This study evaluated biodegradation properties of four novel high-toughness double network (DN) hydrogels as potential materials for artificial cartilage. Concerning each DN gel material, a total of 12 specimens were prepared, and 6 of the 12 specimens were examined to determine the mechanical properties without any treatments. The remaining 6 specimens(More)
We report the surface sliding friction of a high strength gel against a glass substrate under a normal pressure range of 0.01-2.5 MPa. The friction of the gel swollen with different viscous solvents is investigated over a wide velocity range. A velocity-viscosity conversion relationship is established. From the velocity-viscosity conversion relationship, a(More)
We have developed a novel method to induce spontaneous hyaline cartilage regeneration in vivo for a large osteochondral defect by implanting a plug made from a double-network hydrogel composed of poly(2-acrylamido-2-methylpropanesulfonic acid) and poly(N,N'-dimethylacrylamide) at the bottom of the defect, leaving the cavity vacant. In cells regenerated in(More)
The fracture energy G of double network (DN) gels, consisting of poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) as the first network and poly(acrylamide) (PAAm) as the second network, was measured by the tearing test as a function of the crack velocity V. The following results were obtained: (i) The fracture energy G ranges from 10(2) to(More)
Tough triple network (TN) hydrogels that facilitate cell spreading and proliferation and, at the same time, preserve high mechanical strength are synthesized by the introduction of a proper component of negatively charged moiety, poly(2-acrylamido-2-methyl-propane sulfonic acid sodium salt) (PNaAMPS), on which cells proliferate, with neutral moiety,(More)
In this work we describe experiments designed to understand the human platelet adhesion to human umbilical vein endothelial cells (HUVECs) cultured on various kinds of chemically cross-linked anionic hydrogels, which were synthesized by radical polymerization. HUVECs could proliferate to sub-confluent or confluent on poly(acrylic acid) (PAA),(More)
As representative soft materials with widespread applications, gels with various functions have been developed. However, traditional gels are vulnerable to stress-induced formation of cracks. The propagation of these cracks may affect the integrity of network structures of gels, resulting in the loss of functionality and limiting the service life of the(More)
The study evaluated biological reaction of four types of novel double network gels in muscle and subcutaneous tissues, using implantation tests according to the international guideline. The implantation tests demonstrated that, although poly (2-acrylamide-2-metyl-propane sulfonic acid)/poly (N,N'-dimetyl acrylamide) (PAMPS/PDMAAm) gel induced a mild(More)
Weakly crosslinked poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) gel was synthesized and the chemomechanical behaviors in the presence of N-alkylpyridinium chloride (CnPyCl n = 4, 12, 16) were studied. The principle of this behavior is based upon an electrokinetic molecular assembly reaction of surfactant molecules on the polymer gel caused by(More)