Multiplexed flow assay based on absorption-encoded micro beads

1. A method, comprising:

stimulating light emission from k dyes encoding n type of absorption-encoded micro beads present in a sample, each k dye having an absorption spectrum that is distinguishable from absorption spectra of others of the k dyes, wherein stimulating the light emission comprises selectively stimulating each of the k dyes without substantially stimulating others of the k dyes, the k dyes encoding n types of absorption-encoded micro beads, each type of micro bead encoded with amounts of the k dyes in a proportional relationship that is different from proportional relationships of the k dyes of others of the n types of absorption-encoded micro beads;

detecting one or more types of absorption-encoded micro beads present in the sample based on light emission from the k dyes that encode the types of absorption-encoded micro beads; and

analyzing one or more properties of a system using information obtained from detecting the one or more types of absorption-encoded micro beads.

2. The method of claim 1 , wherein detecting the one or more types of absorption-encoded micro beads comprises detecting multiple types of the absorption-encoded micro beads and differentiating between the multiple types.

3. The method of claim 2 , further comprising counting the absorption-encoded micro beads of each micro bead type.

4. The method of claim 1 , wherein the information includes at least one of shape, surface texture, charge, material, hydrophilism, hydrophobism, elasticity, and porosity of the one or more types of absorption-encoded micro beads present in the sample.

5. The method of claim 4 , wherein:

the system comprises a filter; and

the one or more properties comprise filter integrity.

6. The method of claim 1 , wherein:

the system is a biological system;

the sample is taken from the biological system; and

the n-types of absorption-encoded micro beads are added to the sample.

7. The method of claim 1 , wherein:

the n types of micro beads are functionalized with n types of recognition elements, respectively, the n types of recognition elements configured to interact with n analytes, respectively; and

analyzing the one or more properties of the system comprises determining whether one or more of the n analytes are present in the sample.

8. The method of claim 7 , wherein functionalizing the n-types of recognition elements comprises creating an association between the n types of recognition elements and at least one additional dye.

9. The method of claim 8 , wherein the at least one additional dye comprises one or more of Cy 5 and RP-E.

10. The method of claim 8 , wherein 2≦k≦3 and 20≦n≦1000.

11. The method of claim 1 , wherein the k dyes comprise one or more of:

DiA and Pacific Orange;

Pacific Blue and SYTOX Blue;

PerCP and APC; and

chlorophyll a and chlorophyll b.

12. The method of claim 1 , further comprising:

providing excitation light configured to stimulate light emission from a label dye, the light emission indicative of a presence of one or more analytes in the sample;

sensing for light emanating from the micro beads, the light emanating from each micro bead including one or more of light emission from the k dyes and light emission from the label dye; and

detecting one or more target analytes present in the sample based on the light emanating from the micro beads.

13. The method of claim 12 , wherein the n types of absorption-encoded micro beads are functionalized with n recognition elements, respectively, and detecting the one or more target analytes present in the sample comprises identifying multiple target analytes present in the sample.

14. The method of claim 12 , wherein the label dye comprises one or more of:

a fluorophore-conjugated antibody configured to bind to a target analyte causing an increase in the light emanating from the micro beads when the target analyte is present in the sample;

a fluorophore-conjugated antibody configured to bind to a competitor molecule that is displaced from a recognition element of the micro beads by a target analyte causing a decrease in the light emanating from the micro beads when the target analyte is present in the sample;

a fluorophore-conjugated competitor molecule which is displaced from a recognition element of the micro beads by a target analyte causing a decrease in the light emanating from the micro beads when the target analyte is present in the sample;

a fluorophore conjugated to a recognition element of the micro beads, wherein a quencher-conjugated competitor molecule is displaced from a fluorophore-conjugated recognition element of the micro bead by binding to a target analyte, causing an increase in the light emanating from the micro beads when the target analyte is present in the sample.

15. The method of claim 12 , wherein:

providing an excitation light configured to stimulate light emission from the k dyes comprises providing k types of excitation light intensity modulated, respectively, at k frequencies, ν1, ν2, . . . νk;

sensing for the light emanating from the micro beads comprises sensing for light emission modulated at the k frequencies; and

detecting the one or more types of absorption-encoded micro beads present in the sample comprises detecting based on the modulated light emission from the k dyes.

16. The method of claim 12 , wherein:

providing the excitation light configured to stimulate light emission from the label dye comprises providing excitation light modulated at a frequency, ν;

sensing for the light emanating from the micro beads comprises sensing for light emission modulated at frequency ν; and

detecting the one or more target analytes present in the sample comprises detecting based on the light emission modulated at the frequency ν.

17. The method of claim 12 , wherein:

providing excitation light configured to stimulate light emission from the k dyes and providing excitation light configured to stimulate light emission from the label dye comprises providing excitation light modulated at a frequency, ν, for at least one k dye and the label dye; and

sensing for the light emanating from the micro beads comprises separating light emission from the at least one k dye and light emission from the label dye using an optical filter.

18. The method of claim 12 , wherein:

detecting the one or more types of absorption-encoded micro beads present in the sample comprises detecting the one or more types of absorption-encoded micro beads using a first detector channel; and

detecting the one or more target analytes present in the sample comprises detecting the one or more analytes using a second detector channel.

19. The method of claim 18 , wherein:

the absorption-encoded micro beads present in the sample flow through a flow channel;

the first detector channel comprises a first photosensitive detector configured to sense for the light emission from the k dyes; and

the second detector channel comprises a second photosensitive detector configured to sense for the light emission from the label dye, wherein the first photosensitive detector is spaced apart from the flow channel by a first distance and the second photosensitive detector is spaced apart from the flow channel by a second distance, and the first distance is greater than the second distance.