Patent ID: 8377685

Claim:
A microfluidic gradient device comprising: a source assembly adapted to contain a source liquid volume in the range of 25 pL to 15 μL defining a source assembly air/liquid interface having a source assembly radius of curvature comprising a source port having a source port area and source port perimeter in fluid communication with a source reservoir; a sink assembly adapted to contain a sink liquid volume in the range of 500 pL to 100 μL defining a sink assembly air/liquid interface having a sink assembly radius of curvature comprising a sink port having a sink port area and a sink port perimeter in fluid communication with a sink reservoir; a gradient channel adapted to contain a gradient fluid volume in the range of 500 fL to 6 μL, the gradient channel having a gradient height, gradient width, gradient length, gradient transverse cross-sectional area, gradient flow resistance in the range of 1×10 8 to 1×10 18 N-s-m −5 , and, gradient contact angle, the gradient channel in fluid communication with the source reservoir and sink reservoir; and a closed circuit channel adapted to contain a circuit liquid volume in the range of 50 pL to 400 μL, the closed circuit channel having a circuit height, circuit width, circuit length, circuit transverse cross-sectional area, circuit flow resistance in the range of 1×10 6 to 1×10 15 N-s-m −5 , and, circuit contact angle, the closed circuit channel in fluid communication with the source reservoir and sink reservoir, wherein the ratio (gradient flow resistance):(circuit flow resistance) is in the range of (10-10,000):1.