A new type of biomaterial for artificial skin was developed as a form of sponge by combining fibrillar collagen (F-collagen) with gelatin. The sponge was physically and metabolically stabilized by introducing dehydrothermal cross links. To get the final product, various conditions in the preparation of sponges were evaluated by in vitro cellular responses and in vivo tissue reactions. Fibroblasts placed on a sponge of gelatin attached themselves to it, migrated well into the sponge, and remained inside it for at least 7 days. However, sponges of gelatin showed structural instability for hydrolytic degradation by the cells. Most fibroblasts appeared not to penetrate into the interior of a sponge of F-collagen but to remain on its surface when fibroblasts were placed on the sponge, suggesting poor attraction of F-collagen toward cells. Implantation experiments of sponges of F-collagen revealed an intense infiltration of neutrophils into the sponge, indicating F-collagen as an inducer of the inflammatory reaction. These aggravating characters of F-collagen sponges were greatly improved by blending gelatin with F-collagen. The new type of collagen-based biomaterials developed in the present study is expected to become a useful matrix substance for artificial skin.
The interactions of integral‐or pendant‐type polycations with sodium‐1‐anilino‐8‐naphthalene sulfonate (ANS) were studied by means of their fluorescent spectra. The emission maxima shift to the lower wavelength and fluorescent intensities increase greatly as a result of such complexations. This result may be attributed to the electrostatic interaction and the specific nonpolar environment around the bound ANS. The hydrophobic property in the domain formed by a polycation chain depends on the increase of methylene groups or the existence of a xylylene group between two adjacent cationic sites on the main chain, the existence of benzyl groups on the side chains, and the increase of their molecular weights. It is shown that the hydrophobicities in the domains of polyelectrolytes also change with their conformational changes, i.e., the more contracted their conformations are, the stronger their hydrophobicities are.
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