Microfluidic system including a bubble valve for regulating fluid flow through a microchannel
View Patent ↗A microfluidic system includes a bubble valve for regulating fluid flow through a microchannel. The bubble valve includes a fluid meniscus interfacing the microchannel interior and an actuator for deflecting the membrane into the microchannel interior to regulate fluid flow. The actuator generates a gas bubble in a liquid in the microchannel when a sufficient pressure is generated on the membrane.
1. A microfluidic device, comprising:
a microchannel having an interior bounded by a side wall, an inlet, a switching region, and a plurality of outlet channels downstream of the switching region, the microchannel formed in a microfluidic chip substrate and configured to accommodate a flow of liquid through the microchannel;
a valve located in the switching region comprising a sealed reservoir, a side passage extending between the reservoir and the interior of the microchannel via an aperture in the side wall, the side passage configured to accommodate a volume of liquid between the interior of the microchannel and the reservoir; and
an actuator integrated in the microfluidic chip, the actuator configured to increase an internal pressure of the reservoir and move at least a portion of the volume of the liquid from the side passage into the microchannel to deflect a portion of the liquid flowing through the microchannel.
2. The microfluidic device of claim 1 , wherein the actuator is configured to vary the volume of the reservoir.
3. The microfluidic device of claim 1 , wherein actuation of the valve does not block the flow of liquid through the microchannel.
4. The microfluidic device of claim 1 , wherein the actuator comprises one of a piezoelectric actuator and an electromagnetic actuator.
5. The microfluidic device of claim 1 , wherein the sealed reservoir includes a movable wall, and
wherein the actuator deflects the movable wall to increase the internal pressure of the sealed reservoir.
6. The microfluidic device of claim 1 , wherein the sealed reservoir includes a flexible membrane, and
wherein the actuator flexes the flexible membrane to increase the internal pressure of the sealed reservoir.
7. The microfluidic device of claim 1 , wherein a stream of particles in a carrier fluid flows through the microchannel, and
wherein, when the actuator increases the internal pressure of the reservoir, a pressure pulse selectively deflects a particle having a predetermined characteristic from the stream of particles.
8. The microfluidic device of claim 1 ,
wherein increasing the internal pressure of the reservoir generates a pressure pulse within the switching region, and
wherein the pressure pulse travels across the flow direction of the liquid flowing through the microchannel.
9. The microfluidic device of claim 8 , further comprising a second sealed reservoir for absorbing the pressure pulse.