Systems and methods for collecting tear film and measuring tear film osmolarity
A sample receiving chip comprising a substrate that receives an aliquot volume of a sample fluid and a sample region of the substrate, sized such that the volume of the sample fluid is sufficient to operatively cover a portion of the sample region. The energy imparted into the sample fluid is transduced by the sample region to produce an output signal that indicates energy properties of the sample fluid. The sample receiving chip also includes a channel formed in the substrate, the channel configured to collect the aliquot volume of a sample fluid and transfer the aliquot volume of sample fluid to the sample region.
1. A sample receiving chip, comprising:
(a) a substrate that receives a volume of a sample fluid, wherein the substrate is operatively shaped to receive the volume of sample fluid through capillary action,
(b) a capillary channel of the substrate operatively shaped to collect the sample fluid, and
(c) a sample region of the capillary channel comprising at least one transducer, wherein the sample region is configured such that the sample region is operatively covered by the sample fluid when the sample fluid is collected by the capillary channel,
wherein the transducer transfers energy to the sample fluid to produce a sample fluid reading related to the presence or concentration of an analyte of interest in the sample fluid.
2. A chip as defined in claim 1 , wherein the sample fluid reading further indicates osmolarity of the sample fluid.
3. The sample receiving chip of claim 1 , wherein the substrate is formed from a hydrophilic polymer material, resin or glass.
4. The sample receiving chip of claim 1 , wherein the substrate capillary channel has a sinusoidal cross section, a sigmoidal cross section, a triangular cross section, a rectangular cross section, or a truncated Gaussian cross section.
5. The sample receiving chip of claim 1 , wherein the capillary channel has a spatial hybrid cross section, the hybrid being from two or more of the following: sinusoidal, sigmoidal, triangular, rectangular, truncated Gaussian.
6. The sample receiving chip of claim 1 , wherein the substrate is formed using a stratified stack of materials.
7. The sample receiving chip of claim 6 , wherein the strata are formed from a combination of one or more hydrophilic polymers.
8. The sample receiving chip of claim 7 , wherein the hydrophilic polymers comprise one or more of the following: polyether block amides (PEBA), block-copolyether-esters (PEE), polylactic acid (PLA), polyurethanes (PU) including aliphatic and thermoplastic polyurethanes, polyglycolic acid (PGA) and other polyesters (PE), polycaprolactone (PCL), polyethersulfones (PES), polycarbonate (PC).
9. The sample receiving chip of claim 6 , wherein the strata are formed from di- and triblock copolymers.
10. The sample receiving chip of claim 9 , wherein the di- and triblock copolymers are constructed with at least one of the blocks comprising amides, amines, sulfates, phosphates or other charged groups.
11. The sample receiving chip of claim 6 , wherein one or more of the strata include a hydrophilic pressure sensitive adhesive.
12. The sample receiving chip of claim 6 , wherein one or more of the strata are formed from glass.
13. The sample receiving chip of claim 6 , wherein the strata comprise a plurality of layers that decrease in hydrophilicity.
14. The sample receiving chip of claim 6 , wherein the strata comprise a hydrophilic layer sealing a less hydrophilic layer.
15. The sample receiving chip of claim 6 , wherein the strata comprise a hydrophilic layer sealing a hydrophobic layer.
16. The sample receiving chip of claim 6 , wherein at least one of the strata is modified to promote fluid collection.
17. The sample receiving chip of claim 6 , wherein at least one of the strata is modified to lower the contact angle at the edge of the substrate.
18. The sample receiving chip of claim 6 , wherein at least one of the strata is modified to lower the contact angle on the interior of the substrate.
19. The sample receiving chip of claim 6 , wherein at least one of the strata is modified using one of the following: plasma etching, acid treatment, exterior coating, and increased surface roughness.
20. The sample receiving chip of claim 1 , wherein the transducer comprises a plurality of electrodes.
21. The sample receiving chip of claim 1 , wherein the plurality of electrodes is arranged in a row and column array.
22. The sample receiving chip of claim 20 , further comprising a plurality of conductive connection lines coupled to the plurality of electrodes, wherein the conductive connection lines provide means for transferring energy to and from the sample fluid.
23. The sample receiving chip of claim 1 , wherein the sample fluid is bodily fluid.
24. The sample receiving chip of claim 23 , wherein the bodily fluid is tear film.
25. The sample receiving chip of claim 1 , wherein the transducer comprises a plurality of optical indicators.
26. The sample receiving chip of claim 25 , wherein the optical indicators comprise a plurality of luminescent or fluorescent nano-scale spheres.
27. The sample receiving chip of claim 1 , wherein the concentration of the analyte of interest is not normalized against osmolarity of the sample fluid.
28. The sample receiving chip of claim 1 , wherein the capillary channel extends to the edge of the substrate.
29. The sample receiving chip of claim 1 , wherein the capillary channel is situated within the body of the substrate.
30. The sample receiving chip of claim 1 , wherein the volume of the sample fluid is less than 20 μL.
31. The sample receiving chip of claim 1 , wherein the volume of the sample fluid is less than 100nL.
32. The sample receiving chip of claim 1 , wherein the volume of the sample fluid is 10nL.
33. The sample receiving chip of claim 1 , wherein the sample region is further configured to allow light to impart energy transfer within the transduction region.