Analyte concentration detection devices and methods
Arrangements for the detection of the presence and/or concentration of an analyte in a sample of bodily fluid include diffuse transmission, diffuse reflection and edge or waveguide illumination arrangements. A vertical flow assay arrangement and/or technique is also disclosed, and includes a detection component that can be in the form of an array of optical detection elements. A number of assay pad constructions are described which may include at least one or more of the following components: a prefilter component, a reflective component, a membrane component, a reagent component, a mesh component, and a component to prevent lateral spreading.
1. A device for use in conducting an assay to determine the concentration of an analyte in a sample of bodily fluid, the device comprising:
a sample collection chamber having a bottom with at least one opening;
an assay pad in communication with the at least one opening of the chamber, the assay pad comprising a reagent adapted to produce a chemical reaction when exposed to the analyte, the chemical reaction producing a color change in the assay pad; and
a linear array of CMOS optical detectors disposed relative to the assay pad so as to detect the color change, wherein the chamber defines a length, and the linear array has a plurality of CMOS sensors that define a length of the array that is commensurate to the length of the chamber.
2. The device of claim 1 , wherein the analyte comprises glucose.
3. The device of claim 1 , wherein the bodily fluid comprises whole blood.
4. The device of claim 1 , wherein the device further comprises a microneedle.
5. The device of claim 1 , wherein the device is ambulatory.
6. The device of claim 1 , wherein the chamber comprises a microchannel.
7. The device of claim 1 , further comprising a light source adapted to provide light incident upon the assay pad.
8. The device of claim 1 , wherein the light source is arranged relative to the reaction chamber and the assay pad such that light transmitted from the light source is at least partially transmitted through the reaction chamber and the assay pad, the sensor is arranged in a manner such that the transmitted light is received by the sensor.
9. The device of claim 1 , wherein the light source is arranged relative to the reaction chamber and assay pad such that light is transmitted from the light source and at least partially reflected off the assay pad, and the sensor is arranged relative to the reaction chamber and assay pad to receive light reflected off the assay pad.
10. The device of claim 1 , further comprising a waveguide associated with the assay pad, the light source is arranged such that light emitted therefrom is incident upon the waveguide, the waveguide is arranged relative to the assay pad such that light transmitted therein from the light source illuminates the assay pad, the assay pad is constructed to at least partially reflect the light incident thereon, and the detector arranged to receive light by the assay pad.
11. The device of claim 10 , wherein the waveguide is arranged to illuminate a lateral edge of the assay pad, and the sensor is arranged to receive reflected light via the waveguide.
12. The device of claim 10 , wherein at least one side of the waveguide is provided with an antireflective coating.
13. The device of claim 1 , further comprising a lens disposed between each of the sensors and the assay pad.
14. The device of claim 13 , wherein the lens is a refractive lens.
15. The device of claim 13 , wherein the lens is a diffractive lens.
16. The device of claim 13 , wherein the lens is integral with the sensor.
17. The device of claim 1 , wherein the device further comprises a skin penetration member for extracting the sample of bodily fluid from the wearer.
18. The device of claim 1 , wherein the chamber has a general shape of an elongated upside-down U when disposed in its operable position within the device.
19. The device of claim 1 , wherein the chamber defines a volume which is no greater than 250 nanoliters.
20. The device of claim 1 , wherein the assay pad comprises:
a first component constructed to separate red blood cells form plasma and further comprising a diffuse reflective material;
a second component comprising the chemical reagent; and
a third component comprising a polyamide-containing mesh.
21. The device of claim 20 , wherein the diffuse reflective material comprises zirconium oxide.
22. The device of claim 20 , wherein the second component comprises a membrane spin-coated with the chemical reagent.
23. The device of claim 20 , wherein the second and third components are integrated by incorporating the chemical reagent into the polyamide-containing membrane.