MICROFABRICATED STRUCTURES FOR FACILITATING FLUID INTRODUCTION INTO MICROFLUIDIC DEVICES
Fluid introduction is facilitated through the use of a port which extends entirely through a microfluidic substrate. Capillary forces can be used to retain the fluid within the port, and a series of samples or other fluids may be introduced through a single port by sequentially blowing the fluid out through the substrate and replacing the removed fluid with an alternate fluid, or by displacing the fluid in part with additional fluid. In another aspect, microfluidic substrates have channels which varying in cross-sectional dimension so that capillary action spreads a fluid only within a limited portion of the channel network. In yet another aspect, the introduction ports may include a multiplicity of very small channels leading from the port to a fluid channel, so as to filter out particles or other contaminants which might otherwise block the channel at the junction between the channel and the introduction port.
1 . A microfluidic device comprising:
a substrate;
a first microfluidic channel disposed in said substrate; and
a second microfluidic channel disposed in said substrate, said second microfluidic channel being in fluid communication with said first microfluidic channel through a capillary limit region, said capillary limit region being sized to inhibit flow of a first fluid in said first microfluidic channel until a second fluid disposed in said second microfluidic channel contacts said first fluid to define an interfluid boundary therebetween.
2 . The microfluidic device according to claim 1 wherein a cross-sectional area of said first microfluidic channel is smaller than a cross-sectional area of said second microfluidic channel to inhibit wicking of said first fluid from said.
3 . The microfluidic device according to claim 1 wherein said first microfluidic channel terminates into said second microfluidic channel at said capillary limit region.
4 . The microfluidic device according to claim 1 wherein said first fluid comprises a polymer solution suitable for electrophorectic sample manipulation.
5 . The microfluidic device according to claim 1 wherein said second fluid comprises a buffer fluid suitable for electroosmotic sample manipulation.
6 . A microfluidic device comprising:
a substrate;
a first microfluidic channel disposed in said substrate; and
a second microfluidic channel disposed in said substrate, said second microfluidic channel being in fluid communication with said first microfluidic channel through a capillary limit region, said capillary limit region being sized to inhibit flow of a first fluid in said first microfluidic channel until a second fluid disposed in said second microfluidic channel contacts said first fluid to define an interfluid boundary therebetween, said first fluid having a polymer solution suitable for electrophorectic sample manipulation, said second fluid comprising a buffer fluid suitable for electroosmotic sample manipulation.
7 . The microfluidic device according to claim 6 wherein a cross-sectional area of said first microfluidic channel is smaller than a cross-sectional area of said second microfluidic channel to inhibit wicking of said first fluid from said.
8 . The microfluidic device according to claim 6 wherein said first microfluidic channel terminates into said second microfluidic channel at said capillary limit region.
9 . A microfluidic device comprising:
a substrate;
a first microfluidic channel disposed in said substrate;
a second microfluidic channel disposed in said substrate, said second microfluidic channel being in fluid communication with said first microfluidic channel through a capillary limit region, said capillary limit region being sized to inhibit flow of a first fluid in said first microfluidic channel until a second fluid disposed in said second microfluidic channel contacts said first fluid to define an interfluid boundary therebetween; and
a plurality of filter channels in fluid communication with at least one of said first microfluidic channel and said second microfluidic channel.
10 . The microfluidic device according to claim 9 wherein a cross-sectional area of said first microfluidic channel is smaller than a cross-sectional area of said second microfluidic channel to inhibit wicking of said first fluid from said.
11 . The microfluidic device according to claim 9 wherein said first microfluidic channel terminates into said second microfluidic channel at said capillary limit region.
12 . The microfluidic device according to claim 9 wherein said plurality of filter channels is radially disposed.
13 . The microfluidic device according to claim 9 wherein a cross-sectional area of each of said plurality of filter channels is less than a cross-sectional area of said at least one of said first microfluidic channel and said second microfluidic channel.
14 . The microfluidic device according to claim 9 wherein a sum of the cross-sectional areas of said plurality of filter channels is greater than a cross-sectional area of said at least one of said first microfluidic channel and said second microfluidic channel.
15 . A microfluidic device comprising:
a substrate;
a first microfluidic channel disposed in said substrate;
a second microfluidic channel disposed in said substrate, said second microfluidic channel being in fluid communication with said first microfluidic channel through a capillary limit region, said capillary limit region being sized to inhibit flow of a first fluid in said first microfluidic channel until a second fluid disposed in said second microfluidic channel contacts said first fluid to define an interfluid boundary therebetween; and
a plurality of filter channels radially extending and in fluid communication with at least one of said first microfluidic channel and said second microfluidic channel, said plurality of filter channels inhibiting.
16 . The microfluidic device according to claim 15 wherein a cross-sectional area of said first microfluidic channel is smaller than a cross-sectional area of said second microfluidic channel to inhibit wicking of said first fluid from said.
17 . The microfluidic device according to claim 15 wherein said first microfluidic channel terminates into said second microfluidic channel at said capillary limit region.
18 . The microfluidic device according to claim 15 wherein a cross-sectional area of each of said plurality of filter channels is less than a cross-sectional area of said at least one of said first microfluidic channel and said second microfluidic channel.
19 . The microfluidic device according to claim 15 wherein a sum of the cross-sectional areas of said plurality of filter channels is greater than a cross-sectional area of said at least one of said first microfluidic channel and said second microfluidic channel.