Microfluidic devices, particularly filtration devices comprising polymeric membranes, and methods for their manufacture and use

A dialyzer, comprising:

• a semipermeable dialyzer membrane;
• a microchannel fluidic device fluidly associated with the membrane to provide a blood flow adjacent to and on one side of the membrane through a first plurality of microchannels having a first end, a second end and plural parallel channels extending between the first and second ends, and a dialysate flow adjacent to and on a second side of the membrane through a second plurality of microchannels arranged in a counterflow manner with the first plurality of microchannels, the second plurality of microchannels having a first end, a second end and plural parallel channels extending between the first and second ends, wherein the first end of the second plurality of microchannels corresponds to the second end of the first plurality of microchannels;
• a microscale heat exchanger operatively associated with the microchannels;
• a first fluid inlet fluidly coupled to the first plurality of microchannels for delivering blood to the first plurality of microchannels;
• a second fluid inlet fluidly coupled to the second plurality of microchannels for delivering dialysate to the second plurality of microchannels;
• a first plurality of posts uniformly distributed across the first end of the first plurality of microchannels defining a header located adjacent the microchannels for distributing fluid to the first plurality of microchannels to distribute blood flow substantially equally among the first plurality of microchannels;
• and
• a second plurality of posts uniformly distributed across the first end of the second plurality of microchannels defining a header located adjacent the microchannels for distributing dialysate flow substantially equally among the second plurality of microchannels.