Medical device and method of manufacturing using micro-cladding to form functionally graded materials

Abstract

A method of making a method of making a stent includes forming a precursor stent using micro-cladding. The precursor stent includes a plurality of bands made of a first material disposed adjacent to each other and a plurality of connectors connecting each band to an adjacent band. The precursor stent includes a plurality of first connectors configured to remain and a plurality of second connectors made by functionally grading the first material with a second material to create embrittlement. The plurality of second connectors are configured to be removed. The precursor stent is processed to remove the plurality of second connectors without adversely affecting the bands and the plurality of first connectors. The second material may be a radiopaque material.

1 - 27 . (canceled) 
     
     
         28 . A method of making a medical device comprising the steps of:
 forming a precursor medical device using micro-cladding, wherein the precursor medical device comprises a first portion made of a first material, a second portion made of the first material, a first connector configured to remain connecting the first portion to the second portion, and a second connector configured to be removed connecting the first portion to the second portion, wherein the second connector is made by functionally grading the first material with a second material to create embrittlement in the second connector; and   processing the precursor medical device to remove the second connector without adversely affecting the first portion, the second portion, and the first connector.   
     
     
         29 . The method of  claim 28 , wherein the step of processing the precursor medical device to remove the second connector comprises mechanically removing the plurality of second connectors. 
     
     
         30 . The method of  claim 28 , wherein the second material is a radiopaque material. 
     
     
         31 . The method of  claim 28 , wherein the second connector is made by creating abrupt transitions between the first material and the second material. 
     
     
         32 . The method of  claim 28 , wherein the second connector is made by functionally grading the first material and the second material to form detrimental second phase intermetallic compounds to impart embrittlement in the connector. 
     
     
         33 . The method of  claim 28 , wherein first material is selected from the group consisting of a cobalt-chromium alloy and stainless steel, and the second material is selected from the group consisting of tantalum, platinum, and gold. 
     
     
         34 . The method of  claim 28 , wherein the first connector is made by functionally grading the first material and a third material, wherein the third material is a radiopaque material, such that the first connector is radiopaque. 
     
     
         35 . The method of  claim 34 , wherein the step of functionally grading the first material and the third material comprises gradually transitioning from a larger percentage of the first material to a larger percentage of the third material as layers of the first connector are added and then gradually transitioning back from a larger percentage of the third material to the first material as layers are added, such as to minimize the formation of second phase intermetallic compounds in the first connector. 
     
     
         36 . The method of  claim 34 , wherein second material and the third material are the same material. 
     
     
         37 . The method of  claim 28 , wherein a portion of the first portion or the second portion is formed by functionally grading the first material and a third material, wherein the third material is a radiopaque material, such that the portion of the first portion or the second portion is radiopaque. 
     
     
         38 . The method of  claim 37 , wherein the third material and the second material are the same material. 
     
     
         39 . The method of  claim 37 , wherein the step of functionally grading the first material and the third material comprises gradually transitioning from the first material to a larger percentage of the third material than the first material, and then gradually transitioning back from a larger percentage of the third material than the first material to the first material as layers are added, such as to minimize the formation of second phase intermetallic compounds in the portion of the first portion or the second portion. 
     
     
         40 . A method of making a medical device comprising the steps of:
 forming a precursor medical device using micro-cladding, wherein the precursor medical device comprises a first portion made of a first material, a second portion made of the first material, a first connector attaching the first portion to the second portion, and a second connection attaching the first portion to the second portion, wherein at least one portion of the first portion, the second portion, or the first connector is made radiopaque by functionally grading the first material with a second, radiopaque material; and   processing the precursor medical device to remove the plurality of second connectors without adversely affecting the first portion, the second portion, and the first connector.   
     
     
         41 . The method of  claim 40 , wherein the step of functionally grading the first material and the second, radiopaque material for the at least one portion of the first portion, the second portion, or the first connector comprises gradually transitioning from the first material to a larger percentage of the second, radiopaque material than the first material as layers of the at least one portion of the first portion, the second portion, or the first connector are added and then gradually transitioning back from a larger percentage of the second, radiopaque material than the first material to the first material as layers are added, such as to minimize the formation of second phase intermetallic compounds in the at least one portion of the first portion, the second portion, or the first connector. 
     
     
         42 . The method of  claim 41 , wherein the first portion and the second portion comprise a first band including a plurality of struts and crowns connecting the struts and a second band including a plurality of struts and crowns connecting the struts, and the at least one portion of the first portion, the second portion, or the first connector comprises at least one strut of the first band or the second band. 
     
     
         43 . The method of  claim 41 , wherein the at least one portion of the first portion, the second portion, or the first connector comprises the first connector. 
     
     
         44 . A precursor medical device comprising:
 a first portion made of a first material;   a second portion made of a second material;   a first connector connecting the first portion to the second portion; and   a second connector connecting the first portion to the second portion, wherein the first connector is configured to remain and the second connector is made by functionally grading the first material with a second material to create embrittlement such that the second connector is configured to be removed.   
     
     
         45 . The precursor medical device of  claim 44 , wherein the second material is a radiopaque material. 
     
     
         46 . The precursor medical device of  claim 44 , wherein the second connector includes an abrupt transition between the first material and the second material to impart embrittlement at junctions of the second connector with the first portion and the second portion. 
     
     
         47 . The precursor medical device of  claim 44 , wherein the connector includes detrimental second phase intermetallic compounds to impart embrittlement in the second connector. 
     
     
         48 . A medical device comprising:
 a first portion made of a first material;   a second portion made of the first material; and   at least one connector connecting the first portion to the second portion, wherein the at least one connector is made by functionally grading the first material with a second, radiopaque material.   
     
     
         49 . The medical device of  claim 48 , wherein second phase intermetallic compounds are minimized in the at least one connector. 
     
     
         50 . A medical device comprising:
 a first portion made of a first material;   a second portion made of the first material; and   at least one connector connecting the first portion to the second portion,   wherein at least one portion of the first portion or the second portion is made by functionally grading the first material with a second, radiopaque material.   
     
     
         51 . The medical device of  claim 50 , wherein the first portion and the second portion include struts and crowns, with adjacent struts coupled to each other by a corresponding crown, wherein the at least one portion of the first portion or the second portion is a strut of the first portion or the second portion. 
     
     
         52 . The medical device of  claim 51 , wherein second phase intermetallic compounds are minimized in the strut.