Method of controlling the movement of fluid through a microfluidic circuit using an array of triggerable passive valves
The present invention is directed to methods of controlling the flow of fluids through a microfluidic circuit and, more particularly, to methods of controlling the movement of fluid through a microfluidic circuit using one or more triggerable passive valves. In one embodiment of a method of controlling the flow of fluids through a microfluidic circuit according to the present invention, the microfluidic circuit includes a triggerable valve in series with a passive valve. In a further embodiment of a method of controlling the flow of fluids through a microfluidic circuit according to the present invention, the microfluidic circuit includes first and second triggerable valves in parallel.
1. A method of controlling the movement of fluid through a microfluidic circuit including a channel, a first triggerable passive valve and a plurality of passive valves, said method comprising the steps of:
forcing a fluid into said channel at a first pressure which is lower than a burst pressure of said triggerable valve;
triggering said first triggerable valve to move said fluid past said first triggerable valve, said fluid moving past said first triggerable exerting a pressure on said second passive valve which is lower than a burst pressure of said second passive valve;
triggering said first triggerable valve to move said fluid beyond said second passive valve.
2. A method according to claim 1 wherein said microfluidic circuit further includes an analyte sensor positioned in said channel after said first triggerable valve, said method further comprising the step of:
measuring the concentration of analyte in said fluid after said fluid moves past said triggerable valve.
3. A method of controlling the movement of fluid through a microfluidic circuit using a triggeable passive valve to position said fluid over an analyte sensor, said method comprising the steps of:
providing a microchannel having a first segment, a second segment and a third segment, said second segment including said analyte sensor;
positioning a triggerable passive valve in said microchannel between said first segment and said second segment;
positioning a passive valve in said microchannel between said second segment and said third segment;
moving a fluid into said first segment, wherein said fluid exerts a first pressure on said triggerable passive valve;
triggering said triggerable passive valve to move a bolus of said fluid into said second segment wherein said fluid exerts a second pressure on said passive valve;
triggering said triggerable passive valve to move a bolus of said fluid into said third segment;
measuring a quantity indicative of the concentration of an analyte in said fluid using said analyte sensor.
4. A method of controlling the movement of fluid through a microfluidic circuit using a triggeable passive valve according to claim 3 wherein said triggerable passive valve comprises:
a fluid delivery channel having an inlet for receiving fluid and an outlet for discharging fluid, said outlet being downstream from said inlet;
a flow restrictor positioned between said inlet and said outlet;
a first passive valve positioned in said fluid delivery channel downstream from said flow restrictor, said first passive valve having a first predetermined burst pressure, said first passive valve preventing fluid from moving through said channel when the pressure exerted by said fluid on said first passive valve is below said burst pressure;
a control channel having an inlet and an outlet, said control channel outlet being connected to said fluid delivery channel between said flow restrictor and said first passive valve;
a pneumatic actuator connected to said control channel at said control channel inlet;
a second passive valve positioned in said control channel between said control channel inlet and said control channel outlet.
5. A method of controlling the movement of fluid through a microfluidic circuit using a triggeable passive valve according to claim 3 wherein said triggerable passive valve comprises:
a fluid delivery channel having an inlet for receiving fluid and an outlet for discharging fluid downstream from said inlet;
a flow restrictor positioned between said inlet and said outlet;
a first passive valve positioned in said fluid delivery channel downstream from said flow restrictor, said first passive valve having a first predetermined burst pressure, said first passive valve preventing fluid from moving through said channel when the pressure exerted by said fluid on said first passive valve is below said burst pressure;
a bubble chamber connected to said fluid delivery channel between said flow restrictor and said first passive valve;
a second passive valve positioned in said control channel between said control channel inlet and said control channel outlet.
6. A method of controlling the movement of fluid through a microfluidic circuit using a triggeable passive valve to position said fluid over an analyte sensor, said method comprising the steps of:
positioning a first passive valve having a predetermined first burst pressure in a first channel;
positioning a second passive valve having a predetermined second burst pressure in said first channel;
positioning a first flow restrictor in said first channel upstream from said passive valve;
positioning a second flow restrictor in said first channel downstream from said first passive valve and upstream from said second passive valve;
moving a fluid through said channel to said first passive valve, wherein said fluid exerts a pressure on said passive valve;
forcing a gas into said channel between said first flow restrictor and said first passive valve to increase the pressure exerted by said fluid on said first passive valve until the pressure exerted by said fluid exceeds said first burst pressure;
venting said gas from said channel to reduce the pressure exerted by said fluid on said first passive valve;
forcing a gas into said channel between said second flow restrictor and said second passive valve to increase the pressure exerted by said fluid on said second passive valve until the pressure exerted by said fluid exceeds said second burst pressure;
venting said gas from said channel to reduce the pressure exerted by said fluid on said second passive valve.
7. A method of controlling the movement of fluid through a microfluidic circuit using a triggeable passive valve to position said fluid over an analyte sensor, said method comprising the steps of:
positioning a first passive valve having a predetermined first burst pressure in a first channel;
positioning a second passive valve having a predetermined second burst pressure in said first channel;
positioning a first flow restrictor in said first channel upstream from said passive valve;
positioning a second flow restrictor in said first channel downstream from said first passive valve and upstream from said second passive valve;
moving a fluid through said channel to said first passive valve, wherein said fluid exerts a pressure on said passive valve;
generating a gas in said channel between said first flow restrictor and said first passive valve to increase the pressure exerted by said fluid on said first passive valve until the pressure exerted by said fluid exceeds said first burst pressure;
venting said gas from said channel to reduce the pressure exerted by said fluid on said first passive valve;
generating a gas in said channel between said second flow restrictor and said second passive valve to increase the pressure exerted by said fluid on said second passive valve until the pressure exerted by said fluid exceeds said second burst pressure;
venting said gas from said channel to reduce the pressure exerted by said fluid on said second passive valve.