Patent ID: 7935318

Claim:
A microfluidic device, comprising: (a) a microfluidic coupon configured to hold a liquid within a fluid reservoir while the liquid is rotated at a target rotational velocity such that a predetermined degree of centrifugation of the liquid is achieved prior to allowing the liquid to exit therefrom; (b) the fluid reservoir defined by the microfluidic coupon, the fluid reservoir being fluidically connected through a microchannel to a vent located radially inward from the microchannel in the microfluidic coupon, the fluid reservoir being in a non-vented configuration by the vent including a peelable layer or pierceable membrane at an entrance from the vent into the microchannel, or the fluid reservoir being in a vented configuration by the peelable layer or pierceable membrane being peeled or pierced; and the fluid reservoir further being configured to contain the liquid; and (c) an exit opening formed in the fluid reservoir fluidically connected to the vent through the fluid reservoir and the microchannel, and located radially outward on the fluid reservoir in the microfluidic coupon; wherein, when the microfluidic coupon is rotated at the target rotational velocity: (i) the exit opening allows flow of the liquid only when the fluid reservoir is in the vented configuration; and (ii) the exit opening does not allow flow of the liquid when the fluid reservoir is in the non-vented configuration.