Organic/inorganic composite biomaterials and process for producing the same

A process for producing the organic/inorganic composite biomaterials comprising composites of hydroxyapatite and collagen which are constituted of fibers having an average fiber length of 60 μm or longer, said composite having microporous structures in which the c-axis of hydroxyapatite is oriented along collagen fibers, said process comprising:

• simultaneously adding to a reaction vessel an aqueous calcium salt solution and an aqueous phosphate solution containing collagen to maintain the calcium ion concentration at 3.75 mM or lower and the phosphate ion concentration at 2.25 mM or lower in the reaction vessel, and
• pressing the resulting composite,
• wherein the flow rates of the aqueous calcium salt solution and the aqueous phosphate solution being added to the reaction vessel are regulated such that the pH level of the reaction solution in the reaction vessel is maintained between 7 and 11, the average flow rate of the aqueous calcium salt solution being added to the reaction vessel being 5 to 25 ml/min;
• and
• wherein the starting concentration of the aqueous calcium salt solution is 50 to 200 mM, and the starting concentration of the aqueous phosphate solution is 15 to 96 mM.