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 method for detecting or measuring an analyte of interest in tear fluid, comprising:
i. contacting a substrate with an aliquot volume of tear fluid;
ii. transferring optical energy to the aliquot volume of tear fluid; and
iii. detecting energy transfer properties of the aliquot volume of tear fluid to produce a tear fluid reading, wherein the tear fluid reading is correlated to presence or quantity of an analyte of interest in the aliquot volume of tear fluid.
2. The method of claim 1 , comprising detecting the energy transfer properties of the aliquot volume of tear fluid by surface plasmon resonant transduction.
3. The method of claim 1 , further comprising contacting the substrate with an eye of an individual and receiving the aliquot volume of tear fluid.
4. The method of claim 1 , wherein the analyte of interest is a biomarker.
5. The method of claim 1 , wherein the analyte of interest is osmolarity.
6. The method of claim 1 , wherein the analyte of interest is a protein, peptide, or oligonucleotide.
7. The method of claim 1 , wherein the analyte of interest is an immunoglobulin, cytokine or mucin.
8. The method of claim 7 , wherein the analyte of interest is lactoferrin, TGFbeta, TNFalpha, Interleukin 1-A, MUC5 or PRG4.
9. The method of claim 7 , wherein the analyte of interest is IgE, IgM, IgA or a combination thereof.
10. The method of claim 1 , wherein the aliquot volume of tear fluid is less than 20 μl of tear fluid.
11. The method of claim 1 , wherein the aliquot volume of tear fluid is less than 100 nanoliters of tear fluid.
12. The method of claim 1 , wherein the aliquot volume of tear fluid is about 10 nanoliters of tear fluid.
13. The method of claim 1 , wherein the substrate comprises a micropipette or capillary tube.
14. The method of claim 1 , wherein the substrate is part of a sample receiving chip.
15. The method of claim 1 , wherein the substrate comprises a sample region sized such that the aliquot volume of the sample fluid is sufficient to operatively cover a portion of the sample region.
16. The method of claim 1 , wherein the substrate comprises an adhesive.
17. The method of claim 1 , wherein detecting or measuring the analyte of interest comprises use of a biological substance that binds to the analyte of interest.