Metal oxide, metal material, biocompatible material, and method for producing metal oxide

Abstract

Disclosed is a crystalline metal oxide having a positive charge-induced region and a negative charge-induced region, which has a surface which has protrusions and recesses or a porous surface. The metal which configures the metal oxide is preferably an elemental metal or an elemental metal-containing alloy such as titanium, zirconium, titanium alloy, zirconium alloy or cobalt chromium alloy. The metal oxide is preferably one obtained by an anodic oxidation treatment of the metal which configures the metal oxide and the metal oxide can be suitably used as a biocompatible material or a member constituting a biocompatible material.

1 - 15 . (canceled) 
     
     
         16 . A biocompatible material comprising, on at least a part of a surface thereof, a polarized metal oxide coat that is formed of an oxide of a metal selected from the group consisting of titanium, titanium alloy, and cobalt chromium alloy and that comprises a positive charge-induced region and a negative charge-induced region. 
     
     
         17 . The biocompatible material of  claim 16 , wherein the polarized metal oxide coat has a surface comprising protrusions and recesses or is porous, and the negative charge-induced region resides at an outer surface of the polarized metal oxide coat. 
     
     
         18 . The biocompatible material of  claim 16 , wherein a surface of the polarized metal oxide coat comprises a greater number of hydroxyl groups as compared to those existing on the surface before polarization. 
     
     
         19 . The biocompatible material of  claim 16 , wherein the biocompatible material is obtained by: disposing a crystalline metal oxide coat, that is produced by subjecting a base material made of a metal selected from the group consisting of titanium, titanium alloy, and cobalt chromium alloy to oxidization, at a position between a first electrode that functions as a positive electrode and a second electrode that functions as a negative electrode in a state in which the crystalline metal oxide coat is not in contact with one of the first electrode and the second electrode; and applying a voltage to the first electrode and the second electrode. 
     
     
         20 . The biocompatible material of  claim 19 , wherein the oxidization is performed by microarc anodic oxidation. 
     
     
         21 . The biocompatible material of  claim 19 , wherein the voltage application is performed such that an electric field gradient of 0.5 kV/cm or more is formed between the first electrode and the second electrode. 
     
     
         22 . The biocompatible material of  claim 19 , wherein the polarized metal oxide coat has a surface comprising protrusions and recesses or is porous. 
     
     
         23 . A method of producing a biocompatible material, the method comprising:
 subjecting a base material that is made of a metal selected from the group consisting of titanium, titanium alloy, and cobalt chromium alloy to oxidization such that a crystalline metal oxide coat is produced on at least a part of a surface of the base material; and   subjecting the crystalline metal oxide coat to polarization by disposing the crystalline metal oxide coat at a position between a first electrode that functions as a positive electrode and a second electrode that functions as a negative electrode in a state in which the crystalline metal oxide coat is not in contact with at least one of the first electrode or the second electrode, and applying a voltage to the first electrode and the second electrode, such that a positive charge-induced region and a negative charge-induced region are formed in the crystalline metal oxide coat.   
     
     
         24 . The method of  claim 23 , wherein the oxidization is performed by microarc anodic oxidation. 
     
     
         25 . The method of  claim 23 , wherein the voltage application is performed such that an electric field gradient of 0.5 kV/cm or more is formed between the first electrode and the second electrode. 
     
     
         26 . The method of  claim 23 , wherein, in the polarization, the crystalline metal oxide coat is not in contact with one of the first electrode and the second electrode and the base material is in contact with the other one of the first electrode and the second electrode.