Gels formed by low molecular weight gelators occasionally turn into crystals because of the metastable state. In order to improve the defect of low molecular weight gelators, we focused on polymers which can rarely be separated from solution as crystals due to the molecular weight distribution and the entanglement of polymer chain. We prepared polymer type of gelators by covalently attachment of gelation-causing segments on poly(olefin)s. The prepared polymer type of gelators formed physical gels in various solvents. The formed gels were very stable and the gel state remained even after one year. Properties of gelators were studied by gelation tests and the gelation mechanism was cleared by FT-IR, TEM, and FE-SEM.

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Calcium phosphate was coated onto silk fabric using sol-gel processing combined with ultraviolet (UV) irradiation at ambient temperature after dipping and withdrawing silk fabric into and from the sol solution. The calcium phosphate-coated silk fabric had no cytotoxicity, similarly to uncoated silk fabric. Mouse fibroblast adhesion on the calcium phosphate-coated silk fabric was less than that on the uncoated silk fabric. We attributed this low cell adhesion on the calcium phosphate-coated silk fabric to the surface energy change of silk fabric by calcium phosphate coating, not from cytotoxicity. The wound area on the rat skin defect covered with the calcium phosphate-coated silk fabric decreased at a comparable rate with that of commercial silicone gauze. This result demonstrates that the calcium phosphate-coated silk fabric does not prevent the wound healing process. Results of blood coagulation tests showed shorter activated partial thromboplastin time (APTT) of rat plasma contacted with the apatite-coated silk fabric than for plasma contacted with non-coated silk fabric. This result indicates the calcium phosphate-coated silk fabric has a hemostatic effect. We expect the calcium phosphate-coated silk fabric is useful as a wound dressing material with hemostatic effect.

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In order to clarify whether the colorless hematoxylin absorbed in the silk fiber is oxidized to hematein by oxygen in air, the time-course of K/S-λcurve of the silk fabric dyed at the different pH with hematoxylin was investigated by keeping them at ambient temperature and humidity for 40 days. Either of the silk fabrics dyed at pH3.9 and 4.9 were colorless and, if these fabrics were exposed by air for 40days, colored to brownish yellow, implying that hematoxylin inside the fiber was oxidized to hematein. In addition, it was found that a portion of hematein absorbed in silk fabrics dyed at over pH5.9 was faded by oxygen in air. Consequently, the color yield of fabrics during storage was considered to result from a balance of the oxidation of hematoxylin and the discoloration of hematein.

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