Microfluidic sealing valve and microfluidic circuit

A microfluidic sealing valve comprising:

• a primary channel and optionally a secondary channel;
• at least one valve channel having an inlet and an outlet;
• the at least one valve channel in fluid communication with the primary channel or the secondary channel;
• the inlet of the at least one valve channel providing a connection between the at least one valve channel and the primary channel or the secondary channel, the connection between the inlet of the at least one valve channel and the primary channel or the secondary channel having a geometry that permits liquid in the primary channel or the secondary channel to flow into the at least one valve channel through the inlet;
• a void volume having a first port connecting the void volume to the primary channel, the first port having a geometry that inhibits liquid in the primary channel from flowing through the first port into the void volume such that a meniscus moved by a flow of liquid in the primary channel is restrained at the first port, the outlet of the at least one valve channel providing a connection between the at least one valve channel and the void volume,
• wherein a flow of liquid through the primary channel or the secondary channel generates a capillary force that causes the flow of liquid to flow through the inlet into the at least one valve channel, the cross-sectional area of the first port being substantially larger than a cross-sectional area of the at least one valve channel such that a capillary force generated by the flow of liquid through the at least one valve channel causes the meniscus restrained at the first port to expand from the first port into the primary channel, to inhibit flow of liquid in the primary channel past the first port.