Methods of fabricating polymeric structures incorporating microscale fluidic elements

Abstract

The present invention provides a microfluidic device that includes first and second polymeric substrates. The first substrate has a higher transition temperature than the second substrate. A first substantially planar surface of the first substrate has a plurality of microscale channels disposed therein. A first substantially planar surface of the second substrate is thermally bonded to the first surface of the first substrate, neither of the first surfaces of the first and second substrates having an adhesive disposed thereon.

1 . A microfluidic device, comprising:
 a first polymeric substrate comprising a first substantially planar surface having a plurality of microscale channels disposed therein;   a second polymeric substrate comprising a first substantially planar surface, the first surface of the second substrate being thermally bonded to the first surface of the first substrate, neither of the first surfaces of the first and second substrates having an adhesive disposed thereon, wherein the first substrate has a higher transition temperature than the second substrate.   
     
     
         2 . The microfluidic device of  claim 1 , wherein the first polymeric substrate has a first thickness, and wherein the second polymeric substrate has a second thickness, the first thickness being greater than the second thickness. 
     
     
         3 . The microfluidic device of  claim 2 , wherein the thickness of the first polymeric substrate is within a range of 1.0 mm to 3.0 mm. 
     
     
         4 . The microfluidic device of  claim 1 , wherein at least one of the first and second polymeric substrates comprises a copolymer. 
     
     
         5 . The microfluidic device of  claim 1 , wherein the transition temperature of the first substrate is at least 5° C. higher than the transition temperature of the second substrate. 
     
     
         6 . The microfluidic device of  claim 1 , wherein the transition temperature of the first substrate is at least 10° C. higher than the transition temperature of the second substrate. 
     
     
         7 . The microfluidic device of  claim 1 , wherein the transition temperature of the first substrate is at least 20° C. higher than the transition temperature of the second substrate. 
     
     
         8 . The microfluidic device of  claim 1 , wherein the transition temperature of the first substrate is at least 50° C. higher than the transition temperature of the second substrate. 
     
     
         9 . The microfluidic device of  claim 1 , wherein the transition temperature of the first substrate is at least 100° C. higher than the transition temperature of the second substrate. 
     
     
         10 . The microfluidic device of  claim 1 , wherein the plurality of microscale channels in the first surface of the first substrate are embossed in the first surface. 
     
     
         11 . The microfluidic device of  claim 1 , wherein the plurality of microscale channels in the first surface of the first substrate are cast in the first surface. 
     
     
         12 . The microfluidic device of  claim 1 , wherein the first substrate is injection molded. 
     
     
         13 . The microfluidic device of  claim 12 , wherein the plurality of microscale channels in the first surface of the first substrate are molded in the first surface. 
     
     
         14 . The microfluidic device of  claim 1 , wherein at least one of the plurality of channels has a cross-sectional dimension between 0.1 μm and 500 μm. 
     
     
         15 . The microfluidic device of  claim 1 , wherein the second substrate comprises a plurality of apertures disposed therethrough, each aperture being in fluid communication with at least one of the plurality of channels in the first surface of the first substrate. 
     
     
         16 . The microfluidic device of  claim 1 , wherein the first and second substrates comprise different grades of the same polymer. 
     
     
         17 . The microfluidic device of  claim 1 , wherein the first surface of the second substrate does not substantially project into the plurality of channels. 
     
     
         18 . The microfluidic device of  claim 1 , wherein the first surface of the second substrate projects into the plurality of channels less than 10% of a total cross-sectional area of an unobstructed channel. 
     
     
         19 . The microfluidic device of  claim 1 , wherein the first surface of the second substrate projects into the plurality of channels less than 5% of a total cross-sectional area of an unobstructed channel. 
     
     
         20 . The microfluidic device of  claim 1 , wherein the first surface of the second substrate projects into the plurality of channels less than 2% of a total cross-sectional area of an unobstructed channel.