Sample processing device positioning apparatus and methods
Apparatus and methods for positioning the process chambers of microfluidic sample processing devices in the proper focal plane of a microplate reader are disclosed. The apparatus and methods may be adaptable to position the sample processing devices at different heights as may be necessary for processing in different microplate readers. A positioning device is used in connection with the sample processing device to locate the process chambers within the focal plane of the microplate reader.
1. A method of positioning a sample processing device within a microplate reader having a sample compartment with a floor and a focal plane spaced from the floor of the sample compartment, the method comprising:
providing a sample processing device comprising at least one process array, wherein the at least one process array comprises a main conduit and a plurality of process chambers located along the main conduit, and wherein the sample processing device comprises a first major surface with edges at a periphery of the first major surface, and a carrier attached to the top of the major surface of the sample processing device, wherein the carrier comprises compression structures configured to transfer compressive forces to the sample processing device;
locating a positioning device proximate the first major surface of the sample processing device, wherein the positioning device comprises a z-axis thickness and a support surface;
retaining the sample processing device proximate the support surface of the positioning device, wherein the carrier provides sufficient force to flatten the sample processing device; and
locating the sample processing device and the positioning device in the sample compartment of the microplate reader, wherein the positioning device is in contact with the floor of the sample compartment and located between the first major surface of the sample processing device and the floor, wherein the plurality of process chambers are spaced from the floor of the sample compartment by at least a height corresponding to the z-axis thickness, wherein the plurality of process chambers are located within the focal plane of the sample compartment, and wherein the plurality of process chambers would neither be located within the focal plane of the sample compartment nor spaced from the floor of the sample compartment without the positioning device located between the first major surface of the sample processing device and the floor of the sample compartment.
2. A method according to claim 1 , wherein the support surface is substantially coextensive with an area of the first major surface occupied by the plurality of process chambers of the at least one process array, and wherein the support surface is located between the floor and the sample processing device.
3. A method according to claim 2 , wherein the support surface comprises voids formed therein, wherein the first major surface of the sample processing device is visible through the positioning device.
4. A method according to claim 1 , further comprising determining a position of a focal plane within the sample compartment and selecting a positioning device that positions the plurality of process chambers of the at least one process array within the focal plane within the sample compartment when the sample processing device and the positioning device are located within the sample compartment and the positioning device is located between the first major surface of the sample processing device and the floor of the sample compartment.
5. A method according to claim 1 , further comprising registering the sample processing device on a support surface of the positioning device.
6. A method according to claim 1 , wherein the positioning device comprises alignment features that mate with complementary alignment features on the sample processing device.
7. A method according to claim 6 , wherein the alignment features of the positioning device comprise posts protruding from a support surface of the positioning device and wherein the complementary alignment features of the sample processing device comprise openings sized to receive the posts protruding from the support surface of the positioning device.
8. A method according to claim 6 , wherein the alignment features of the positioning device comprise openings in the support surface of the positioning device, and wherein the complementary alignment features of the sample processing device comprise posts protruding from the first major surface of the sample processing device, wherein the openings in the positioning device are sized to receive the posts protruding from the first major surface of the sample processing device.
9. A method according to claim 1 , wherein the retaining comprises clamping the positioning device and the sample processing device together.
10. A method according to claim 1 , wherein the retaining comprises adhering the positioning device and the sample processing device together.
11. A method according to claim 1 , wherein the retaining comprises capturing a post in a locking tab.
12. A method according to claim 1 , wherein the sample processing device is not fixedly attached to the positioning device when the sample processing device and the positioning device are located within the sample compartment and the positioning device is located between the first major surface of the sample processing device and the floor of the sample compartment.
13. A method according to claim 1 , wherein the sample processing device and the positioning device are rotationally connected to each other by one or more hinges.
14. The method according to claim 1 , wherein the sample processing device is a microfluidic device.
15. The method according to claim 1 , wherein the positioning device further comprises a base surface opposite the support surface, said base substantially coextensive with the support surface and resting on the floor when the positioning device is located in the sample compartment.