Self-Detaching Layer for Easy Implant Removal

Abstract

A bone implant includes (a) a first layer provided over a first outer surface of the bone implant and being formed of a first material which is one of water-soluble and degradable in body fluids, the first layer having a first thickness and (b) a second layer provided over an outer periphery of the first layer and being formed of a biocompatible material, the second layer having a second thickness smaller than the first thickness.

1 . A bone implant, comprising:
 a first layer provided over a first outer surface of the bone implant and including a first material which is one of water-soluble and degradable in body fluids, the first layer having a first thickness; and   a second layer provided over an outer surface of the first layer and formed of a second, biocompatible material, the second layer having a second thickness smaller than the first thickness.   
     
     
         2 . The implant according to  claim 1 , wherein the second layer includes a bioresorbable or bio-dissolving material. 
     
     
         3 . The implant according to  claim 1 , wherein the second layer includes a non-resorbable or non-dissolving material. 
     
     
         4 . The implant according to  claim 3 , wherein the second thickness is between 1 nm and 100 nm. 
     
     
         5 . The implant according to  claim 2 , wherein a resorption/dissolution rate of the second layer is smaller than a resorption/dissolution rate of the first layer. 
     
     
         6 . The implant according to  claim 5 , wherein the resorption/dissolution rate of the second layer is between two weeks and three months after implantation in vivo. 
     
     
         7 . The implant according to  claim 1 , wherein the first layer is made of a resorbable material. 
     
     
         8 . The implant according to  claim 1 , wherein the first thickness of the first layer is between approximately 10 μm and 1000 μm, the ratio of the first thickness to the second thickness being in the range of 10,000:1 and 1,000:1. 
     
     
         9 . The implant according to  claim 1 , wherein the first layer is formed of one of polyvinyl alcohol (PVA) and a polylactide. 
     
     
         10 . The implant according to  claim 9 , wherein the second layer is formed of a non-resorbable metal, preferably titanium or a titanium alloy with a maximum second thickness of 100 nm. 
     
     
         11 . The implant according to  claim 9 , wherein the second layer is formed of hydroxyapatite and has a maximum second thickness of 10 μm. 
     
     
         12 . The implant according to  claim 1 , wherein at least one of the first and second layers comprises at least one biodegradable metal or metal alloy selected from a group comprising magnesium, iron and alloys thereof. 
     
     
         13 . The implant according to  claim 1 , further comprising an intermediary layer interposed between the first layer and the second layer, the intermediary layer being formed of a mixture of the materials of the first and second layers. 
     
     
         14 . The implant according to  claim 1 , further comprising a third layer provided over an outer surface of the second layer, the third layer being formed of a material which is one of water-soluble and degradable in body fluids. 
     
     
         15 . The implant according to  claim 14 , further comprising a fourth layer provided over an outer surface of the third layer, the fourth layer being formed of a biocompatible material. 
     
     
         16 . The implant according to  claim 15 , wherein the number of alternating layers comprising a material which is water-soluble or degradable in body fluids and a biocompatible material is 2 x; x being 3 or larger. 
     
     
         17 . The implant according to  claim 1 , wherein the material of the first layer is different from the material of the second layer. 
     
     
         18 . A method for manufacturing a bone implant, comprising:
 applying a first layer of a first material over a first surface of the bone implant, the first material being one or both of water-soluble and degradable in body fluids; and   applying a second layer of a second material over an outer surface of the first layer, the second material being biocompatible.   
     
     
         19 . The method according to  claim 18 , further comprising the step of applying an intermediary layer over the first layer prior to applying the second layer, the intermediary layer being formed of a mixture of the first and second materials. 
     
     
         20 . The method according to  claim 18 , wherein the first and second layers are applied by one of dip coating and spray coating.