Instrument for performing a diagnostic test on a fluidic cartridge

1. A cartridge reader for carrying out a diagnostic test on a sample contained in a fluidic cartridge comprising a mechanical valve for isolating the sample with the cartridge, the cartridge reader comprising a system for actuating the mechanical valve comprising:

an actuation member configured to move the mechanical valve from an open position to a closed position;

an armature connected to the actuation member, configured to engage an electromagnet, wherein the electromagnet can be switched between an active state in which it electromagnetically holds the armature and an inactive state in which it does not electromagnetically hold the armature;

a first biasing means, disposed between the actuation member and a bearing surface, wherein the first biasing means is configured to bias the actuation member into a first position in which it actuates a mechanical valve in a fluidic cartridge inserted into the reader;

wherein the actuation member is held in a second position against the bias of the first biasing means by the electromagnet when the electromagnet is in its active state, and is moved into its first position by the first biasing means when the electromagnet is in its inactive state;

an upper clamp having a fixed position relative to the cartridge reader and a lower clamp, movable relative to the upper clamp, wherein the upper clamp and the lower clamp are configured to receive the fluidic cartridge therebetween;

a gantry, fixedly connected to the lower clamp by at least one alignment shaft which passes through at least one aperture in the upper clamp such that at least a portion of the gantry extends above the upper clamp, wherein the electromagnet is connected to the gantry and the bearing surface is comprised in the upper clamp; and

a processing means for controlling operation of the cartridge reader and configured to determine when a diagnostic test carried out by the reader has been completed, and to switch the electromagnet to its inactive state at the end of the diagnostic test so as to move the mechanical valve from an open position to a closed position to isolate the sample within the cartridge.

2. The cartridge reader of claim 1 , wherein, in the event of a fault or power failure, the electromagnet becomes inactive and the mechanical valve moves to its closed position to isolate the sample.

3. The cartridge reader of claim 2 , wherein the armature and the actuation member are connected by a shaft which passes through an aperture in the upper clamp.

4. The cartridge of claim 2 , wherein the reader is further configured to:

move the lower clamp from a first position in which the electromagnet mounted on the gantry is spaced apart from the armature when the armature is in its first position, to a second position in which the electromagnet contacts the armature;

activate the electromagnet when it reaches the second position, thereby engaging the electromagnet with the armature; and

move the lower clamp from its second position to a third position, whilst magnetically holding the armature, thereby moving the actuation member to its second position.

5. The cartridge of claim 4 , further comprising a first coil spring disposed around the at least one alignment shaft, between the actuation member and the upper clamp.

6. The cartridge reader of claim 4 , wherein central axes of the electromagnet, the alignment shaft and the actuation member are offset from each other.

7. The cartridge reader of claim 6 , wherein the first biasing means comprises a coil spring, and wherein each of the axes is within a circumference of the first biasing means.

8. The cartridge reader of claim 2 , further comprising second biasing means between the upper clamp and the gantry.

9. The cartridge reader of claim 8 , wherein a force exerted by the second biasing means exceeds the force exerted by the first biasing means.

10. A fluidic cartridge for carrying out a diagnostic test on a sample contained therein, the cartridge comprising a mechanical valve for isolating the sample with the cartridge and configured for use with a cartridge reader of claim 1 , the mechanical valve configured to be moved from an open position to a closed position by the actuation member.