Abstract: A complex of a carboxyalkyl ether of a polysaccharide with a magnetic metal oxide. This complex is extremely excellent in stability in preservation in the form of aqueous sol and has only a low toxicity, and thus is useful, for example, for medical use as a nuclear magnetic imaging molding agent or the like.

Abstract: A biocompatible composite material comprising a substrate having a glass-hydroxyapatite ceramic layer disposed thereon, and optionally having an intermediate glass layer between the substrate and the layer. The glass-hydroxyapatite ceramic layer comprises a continuous glass phase having a hydroxyapatite ceramic dispersed therein, said hydroxyapatite ceramic having a calcium/phosphorous molar ratio of 1.50 to 1.75, wherein said hydroxyapatite ceramic is comprised mainly of hydroxyapatite. The surface portion of the layer is in a roughened state having voids and having the hydroxyapatite ceramic exposed. The composite material may be produced by a method comprising applying a blend of a powdery glass with a hydroxyapatite ceramic to the surface of a substrate with or without a glass layer disposed thereon, firing the resulting coated substrate and subjecting the fired coated substrate to an etching action with an acid.