Patent ID: 7459127

Claim:
A microfluidic device for dispensing and analyzing a uniform volume of a liquid sample comprising: (a) a sample well for receiving and transferring a portion of said liquid sample; (b) a hydrophilic capillary passageway in liquid communication with said sample well of (a) for receiving a portion of said sample from said sample well of (a), a segment of said hydrophilic capillary passageway disposed between two vents from said hydrophilic capillary passageway to the atmosphere, said segment defining said uniform volume of said liquid sample; (c) a transfer hydrophilic capillary passageway in liquid communication between said segment of said hydrophilic capillary passageway of (b) and a reagent well, said transfer hydrophilic capillary passageway entering said segment between said two vents to atmosphere, whereby when said uniform volume of said segment is transferred to said reagent well air enters said segment from said two vents and displaces said uniform of liquid sample, (d) a hydrophilic capillary stop disposed within said transfer hydrophilic capillary passageway of (c) between the entrance to said segment and said reagent well, said capillary stop for preventing transfer of said uniform sample volume until the resistance of said capillary stop is overcome by a means for applying force using pressure, vacuum, or electroosmosis.