Microneedle devices and methods of manufacture

Abstract

Microneedle devices and methods of manufacturing the microneedle devices. The microneedle devices include microneedles protruding from a substrate, with the microneedles piercing a cover placed over the substrate surface from which the microneedles protrude. The cover and the microneedle substrate together define a capillary volume in fluid communication with the base of each microneedle. One manner of using microneedle arrays of the present invention is in methods involving the penetration of skin to deliver medicaments or other substances and/or extract blood or tissue. Manufacturing methods may include simultaneous application of pressure and ultrasonic energy when piercing the cover with the microneedles.

1 . A microneedle device comprising: 
 a substrate comprising a first major surface and a second major surface;    at least one microneedle projecting from the first major surface of the substrate, the at least one microneedle comprising a base proximate the first major surface of the substrate and a tip distal from the base;    a cover comprising a first side facing the first major surface of the substrate and a second side facing away from the substrate, wherein the at least one microneedle penetrates through the first side and the second side of the cover;    a capillary volume located between the first major surface of the substrate and the first side of the cover; wherein the capillary volume contacts at least a portion of the base of the at least one microneedle;    a backing proximate the second major surface of the substrate, wherein the backing extends past a periphery of the substrate; and    a cap attached to the backing around the periphery of the substrate, wherein the first major surface of the substrate faces the cap, and wherein the substrate and the at least one microneedle are enclosed between the backing and the cap.    
     
     
         2 . A device according to  claim 1 , wherein the at least one microneedle comprises a plurality of microneedles.  
     
     
         3 . A device according to  claim 1 , wherein the cover comprises a liquid impermeable film.  
     
     
         4 . A device according to  claim 1 , wherein the cap is adhesively attached to the backing outside of the periphery of the substrate.  
     
     
         5 . A device according to  claim 1 , wherein the cap is thermally bonded to the backing outside of the periphery of the substrate.  
     
     
         6 . A device according to  claim 1 , wherein the backing and the cap comprise a moisture-impermeable package enclosing the substrate and the at least one microneedle.  
     
     
         7 . A device according to  claim 1 , wherein the backing is adhesively attached to the first side of the cover outside of the periphery of the substrate.  
     
     
         8 . A device according to  claim 1 , wherein the cover extends outside of the periphery of the substrate, and wherein the backing is attached to the first side of the cover outside of the periphery of the substrate, wherein the substrate is located between the cover and the backing.  
     
     
         9 . A device according to  claim 8 , wherein the backing is adhesively attached to the first side of the cover outside of the periphery of the substrate.  
     
     
         10 . A device according to  claim 8 , wherein the backing is thermally bonded to the first side of the cover outside of the periphery of the substrate.  
     
     
         11 . A device according to  claim 1 , further comprising a sensor element in fluid communication with the capillary volume.  
     
     
         12 . A device according to  claim 11 , further comprising an electrically conductive pattern, wherein a portion of the electrically conductive pattern is in contact with the sensor element.  
     
     
         13 . A device according to  claim 1 , further comprising a glucose test element in fluid communication with the capillary volume, wherein the device further comprises an electrically conductive pattern comprising an anode and a cathode in contact with the glucose test element.  
     
     
         14 . A method of manufacturing a microneedle device comprising: 
 providing a substrate comprising a first major surface and at least one microneedle projecting from the first major surface of the substrate, the at least one microneedle comprising a base proximate the first major surface of the substrate and a tip distal from the base;    providing a cover comprising a first side facing the first major surface of the substrate;    forcing the tip of the at least one microneedle through the cover; and    forming a capillary volume located between the first major surface of the substrate and the first side of the cover; wherein the capillary volume contacts at least a portion of the base of the at least one microneedle.    
     
     
         15 . A method according to  claim 14 , wherein the at least one microneedle comprises a plurality of microneedles, and wherein tips on the plurality of microneedles are forced through the cover.  
     
     
         16 . A method according to  claim 14 , ,further comprising applying ultrasonic energy to the substrate while forcing the tip of the at least one microneedle through the cover film.  
     
     
         17 . A method according to  claim 14 , wherein forcing the tip of the at least one microneedle through the cover film further comprises forcing the tip of the at least one microneedle into a resilient surface.  
     
     
         18 . A method according to  claim 14 , further comprising applying ultrasonic energy to the substrate while forcing the tip of the at least one microneedle through the cover film, and wherein forcing the tip of the at least one microneedle through the cover film further comprises forcing the tip of the at least one microneedle into a resilient surface.  
     
     
         19 . A method according to  claim 14 , wherein the cover comprises a liquid impermeable film.  
     
     
         20 . A method according to  claim 14 , wherein the cover comprises a polymeric film.  
     
     
         21 . A method according to  claim 14 , wherein the capillary volume comprises conduit structures formed by the substrate.  
     
     
         22 . A method according to  claim 14 , further comprising standoff structure located within the capillary volume, the standoff structure at least partially defining the capillary volume.  
     
     
         23 . A method according to  claim 22 , wherein the standoff structure defines directional channels extending in at least one selected direction.  
     
     
         24 . A method according to  claim 14 , further comprising standoff structure located within the capillary volume, the standoff structure at least partially defining the capillary volume, wherein the standoff structure protrudes from the first major surface of the substrate.  
     
     
         25 . A method according to  claim 14 , further comprising standoff structure located within the capillary volume, the standoff structure at least partially defining the capillary volume, wherein the standoff structure protrudes from the first side of the substrate.  
     
     
         26 . A method according to  claim 14 , further comprising providing a porous layer within the capillary volume, wherein the capillary volume is substantially located within the porous structure.  
     
     
         27 . A method according to  claim 14 , further comprising providing a hydrophilic surface within the capillary volume.  
     
     
         28 . A method according to  claim 27 , wherein the hydrophilic surface comprises a coating.  
     
     
         29 . A method according to  claim 14 , further comprising a channel formed in an outer surface of the at least one microneedle, the channel extending from the base towards the tip of the at least one microneedle.  
     
     
         30 . A method according to  claim 29 , wherein the channel is in fluid communication with the capillary volume.  
     
     
         31 . A method according to  claim 14 , further comprising providing a sensor element in fluid communication with the capillary volume.  
     
     
         32 . A method according to  claim 31 , further comprising providing an electrically conductive pattern, wherein a portion of the electrically conductive pattern is in contact with the sensor element.  
     
     
         33 . A method according to  claim 14 , further comprising providing a glucose test element in fluid communication with the capillary volume, wherein the method further comprises providing an electrically conductive pattern comprising an anode and a cathode in contact with the glucose test element.  
     
     
         34 . A method according to  claim 14 , further comprising providing an adhesive layer on the second side of the cover.  
     
     
         35 . A method according to  claim 14 , wherein the cover extends outside of a periphery of the substrate, and wherein the method further comprises attaching a backing to the first side of the cover outside of the periphery of the substrate, wherein the substrate is located between the cover and the backing.  
     
     
         36 . A method according to  claim 35 , wherein the substrate comprises a second major surface facing the backing, and wherein the method comprises attaching the backing to the second major surface of the substrate.  
     
     
         37 . A method according to  claim 35 , wherein the backing is adhesively attached to the first side of the cover outside of the periphery of the substrate.  
     
     
         38 . A method according to  claim 35 , wherein the backing is thermally bonded to the first side of the cover outside of the periphery of the substrate.  
     
     
         39 . A method according to  claim 14 , further comprising enclosing the substrate and the at least one microneedle by: 
 providing a backing proximate the second major surface of the substrate, wherein the backing extends past a periphery of the substrate; and    attaching a cap to the backing around the periphery of the substrate, wherein the first major surface of the substrate faces the cap.    
     
     
         40 . A method according to  claim 39 , wherein the backing and the cap comprise a moisture-impermeable package enclosing the substrate and the at least one microneedle.