Electroporation Microneedle and Methods For Its Use

Abstract

Electroporation of cells in target tissues is performed using microneedles having integral electrode structures. In a first embodiment, a pair of electrode structures are disposed on opposite sides of a substance delivery opening on a needle or other tissue-penetrating shaft. In a second embodiment, a first electrode structure is disposed on the needle and a second electrode structure is disposed on an attached base. The electrode structures are spaced closely together and relatively low voltages are applied to achieve electroporation-enhanced substance delivery.

1 . A method for delivering substances to solid tissue, said method comprising: 
 penetrating a shaft into the solid tissue;    delivering the substance through the shaft to a target site in the solid tissue; and    applying an electric field to the target site through an electrode structure on the shaft.    
   
   
       2 . A method as in  claim 1 , wherein the substance comprises a nucleic acid.  
   
   
       3 . A method as in  claim 1 , wherein the substance comprises a protein.  
   
   
       4 . A method as in  claim 1 , wherein the substance comprises a small molecule drug.  
   
   
       5 . A method as in  claim 1 , wherein applying an electric field comprises delivering current between a first electrode structure on the shaft and a second electrode structure spaced-apart by a preselected distance on the shaft.  
   
   
       6 . A method as in  claim 5 , wherein the preselected distance is in the range from 10 μm to 2 mm.  
   
   
       7 . A method as in  claim 6 , wherein the substance is delivered through a location on the shaft between the first and second electrode structures.  
   
   
       8 . A method as in  claim 7 , wherein the electrode structures have areas in contact with the solid tissue in the range from 0.0001 mm 2  to 4 mm 2 .  
   
   
       9 . A method as in  claim 1 , wherein applying an electric field comprises delivering current between a first electrode structure on the shaft and a second electrode structure on the base.  
   
   
       10 . A method as in  claim 9 , wherein the first and second electrode structures are spaced-apart by a distance less than 2 mm.  
   
   
       11 . A method as in  claim 9 , wherein the substance is delivered through a location on the shaft proximate the first electrode structure.  
   
   
       12 . A method as in  claim 11 , wherein the first electrode structure has an area in the range from 0.0001 mm 2  to 4 mm 2  and the second electrode structure has an area in the range from 0.01 mm 2  to 100 mm 2.