Techniques and devices associated with blood sampling
The present invention generally relates to devices and techniques associated with diagnostics, therapies, and other applications, including skin-associated applications, for example, devices for delivering and/or withdrawing fluid from subjects, e.g., through the skin. In some embodiments, the device includes a system for accessing an extractable medium from and/or through the skin of the subject at an access site, and a pressure regulator supported by a support structure, able to create a pressure differential across the skin at at least a portion of the access site. The device may also include, in some cases, a sensor supported by the support structure for determining at least one condition of the extractable medium from the subject, and optionally a signal generator supported by the support structure for generating a signal relating to the condition of the medium determined by the sensor.
1. A device for withdrawing blood from the skin and/or from beneath the skin of a subject, the device comprising:
(a) a recess configured and arranged to be sealingly placed against the skin;
(b) a plurality of microneedles configured and arranged to be applied to skin within the recess;
(c) a vacuum chamber having an internal negative pressure before blood is withdrawn into the device and before the device is applied to the skin of the subject;
(d) a storage chamber, separate from the vacuum chamber and the recess, for receiving blood withdrawn into the recess when the negative pressure from the vacuum chamber is applied to the skin of the subject;
(e) an activator that, when activated, fluidly communicates the negative pressure from the vacuum chamber to the recess, wherein prior to activating the activator, the device comprises the vacuum chamber and the recess, and the negative pressure from the vacuum chamber is not in fluid communication with the recess; and
(f) a microfluidic channel fluidly communicating the vacuum chamber and the storage chamber prior to activation, the microfluidic channel being discrete from the vacuum chamber and the storage chamber and having a smaller cross-sectional area than the cross-sectional area of the storage chamber.
2. The device of claim 1 , wherein at least some of the microneedles are solid.
3. The device of claim 1 , wherein at least some of the microneedles are hollow.
4. The device of claim 1 , wherein the device is self-contained.
5. The device of claim 1 , wherein the device comprises at least 6 microneedles.
6. The device of claim 1 , further comprising a support structure constructed and arranged to move the plurality of microneedles into contact with the skin, and to withdrawal the plurality of microneedles from the skin after contact with the skin.
7. The device of claim 1 , the device further comprising a flow controller able to control blood flow into the storage chamber.
8. The device of claim 7 , wherein the flow controller comprises a membrane.
9. The device of claim 1 , wherein the vacuum chamber does not have a variable volume.
10. The device of claim 1 , further comprising a reaction entity contained within the storage chamber able to react with an analyte contained within the blood.
11. A device for withdrawing blood from the skin and/or from beneath the skin of a subject, the device comprising:
a fluid transporter comprising one or more microneedles;
a vacuum chamber having an internal negative pressure before blood is withdrawn into the device and before the device is applied to the skin of the subject;
a storage chamber, separate from the vacuum chamber, for receiving blood withdrawn into the device when the negative pressure from the vacuum chamber is applied to the skin of the subject; and
an activator comprising a component activatable by a subject and a portion that, when activated, fluidly communicates the negative pressure from the vacuum chamber to a recess, wherein prior to activating the activator, the device comprises the vacuum chamber and the recess, and the negative pressure from the vacuum chamber is not in fluid communication with the recess.
12. The device of claim 11 , wherein at least some of the one or more microneedles are solid.
13. The device of claim 11 , wherein at least some of the one or more microneedles are hollow.
14. The device of claim 11 , wherein the device is self-contained.
15. The device of claim 11 , wherein the device comprises at least 6 microneedles.
16. The device of claim 11 , further comprising a support structure constructed and arranged to move the one or more microneedles into contact with the skin, and to withdrawal the plurality of microneedles from the skin after contact with the skin.
17. The device of claim 11 , the device further comprising a flow controller able to control blood flow into the storage chamber.
18. The device of claim 17 , wherein the flow controller comprises a membrane.
19. The device of claim 11 , wherein the vacuum chamber does not have a variable volume.
20. The device of claim 11 , further comprising a reaction entity contained within the storage chamber able to react with an analyte contained within the blood.
21. The device of claim 11 , wherein the device is constructed and arranged to prevent blood from entering the vacuum chamber.