Abstract: A microfluidic sealing valve 1 comprises a primary channel 2, a valve channel 4, and a geometry that permits liquid in the primary channel 2 to flow into the valve channel 4 through an inlet 5. Liquid in the primary channel 2 is inhibited from flowing through a first port 8 into the void volume 7. A meniscus 9 moved by a flow of liquid in the primary channel 2 is restrained at the first port 8. A flow of liquid through the primary channel 2 generates a capillary force that causes the flow of liquid to flow into the valve channel 4. A capillary force generated by the flow of liquid through the valve channel 4 causes the meniscus 9 to expand from the first port 8 into the primary channel, to inhibit flow of liquid in the primary channel 2 past the first port 8.