Retro-Percussive Technique for Creating Nanoscale Holes

Abstract

A method of forming extremely small pores in glass or a similar substrate, useful, for example, in patch clamp applications, that employs a backer plate to contain energy of a laser-induced ablation through the front surface of the substrate so as to create a rear surface shock wave providing a fire polishing of the exit aperture of the pore such as produces improved sealing with cell membranes.

1 .- 10 . (canceled) 
     
     
         11 . A patch clamp comprising:
 a substrate having at least one hole passing therethrough, the hole having a minimum internal diameter less than 1000 nm and being hour-glass shaped to have outwardly concave apertures from a front and rear surface.   
     
     
         12 . The patch clamp of  claim 11  wherein a slope of the aperture on the rear surface is substantially larger than the slope of the aperture on the front surface. 
     
     
         13 . The patch clamp of  claim 11  wherein at least one concave aperture is fire polished. 
     
     
         14 . The patch clamp of  claim 11  wherein the substrate material is glass. 
     
     
         15 . The patch clamp of  claim 11  wherein the substrate material is borosilicate glass. 
     
     
         16 . The patch clamp of  claim 11  wherein at least one of the outwardly concave apertures has a cross-sectional area that reduces magnitude at a variable rate of change as a function of a distance from the respective at least one of the front and rear surfaces, and wherein the cross-sectional area of the at least one of the outwardly concave apertures reduces at (i) a relatively greater rate toward the minimum internal diameter of the hole and, (ii) a relatively lesser rate away from the minimum internal diameter of the hole. 
     
     
         17 . A patch clamp comprising:
 a substrate having an outer surface and a hole that extends through the substrate; and   a crater that extends into the outer surface of the substrate and at least partially defines the hole, the crater being outwardly concave so as to face toward the outer surface of the substrate, the outwardly concave crater being defined by a wall that includes an outer wall portion that is provided relatively closer to the outer surface of the substrate and an inner wall portion that is provided relatively further from the outer surface of the substrate,   wherein (i) the outer wall portion of the crater defines a slope that is relatively closer to orthogonal with respect to the outer surface of the substrate than the inner wall portion of the crater, and (ii) the inner wall portion of the crater defines a slope that is relatively closer to parallel to the outer surface of the substrate than the outer wall portion of the crater.   
     
     
         18 . The patch clamp of  claim 17  wherein the outer surface of the substrate defines a first surface of the substrate and the substrate includes a second opposing surface, the crater defining a first crater extending into the first surface of the substrate and the substrate further including a second crater that extends into the second surface of the substrate and intersects with the first crater, and wherein a minimum internal diameter of the hole is defined at the intersection of the first and second craters. 
     
     
         19 . The patch clamp of  claim 18  wherein the second crater is outwardly concave so as to face toward the second surface of the substrate. 
     
     
         20 . The patch clamp of  claim 17  wherein the hole has a minimum internal diameter that is less than 1000 nm. 
     
     
         21 . The patch clamp of  claim 20  wherein the hole defines an hour-glass shape. 
     
     
         22 . The patch clamp of  claim 17  wherein the crater is fire polished. 
     
     
         23 . The patch clamp of  claim 17  wherein the substrate is a glass material. 
     
     
         24 . A patch clamp comprising:
 a substrate having an outer surface and a hole that extends through the substrate; and   a crater that extends into the outer surface of the substrate and at least partially defines the hole, the crater having a crater cross-sectional area that varies as a function of a depth of the crater, so that the crater cross-sectional area is relatively larger at a shallower crater depth defined toward the outer surface of the substrate and the crater cross-sectional area is relatively smaller at a deeper crater depth defined away from the outer surface of the substrate,   wherein the crater cross-sectional area decreases at different rates of change as a function of crater depth such that the crater cross-sectional area is reduced at a greater rate toward the deeper crater depth along a traverse from the shallower crater depth toward the deeper crater depth.   
     
     
         25 . The patch clamp of  claim 24  wherein the outer surface of the substrate defines a first surface of the substrate and the substrate includes a second opposing surface, the crater defining a first crater extending into the first surface of the substrate and the substrate further including a second crater that extends into the second surface of the substrate and intersects with the first crater, and wherein a minimum internal diameter of the hole is defined at the intersection of the first and second crater. 
     
     
         26 . The patch clamp of  claim 25  wherein the second crater has a crater cross-sectional area that varies as a function of a depth of the second crater. 
     
     
         27 . The patch clamp of  claim 26  wherein the crater cross-sectional area of the second crater is relatively larger at a shallower crater depth defined toward the second surface of the substrate and the crater cross-sectional area is relatively smaller at a deeper crater depth defined away from the second surface of the substrate. 
     
     
         28 . The patch clamp of  claim 24  wherein the hole has a minimum internal diameter that is less than 1000 nm.