Non-invasive monitoring cancer using integrated microfluidic profiling of circulating microvesicles
A microfluidic exosome profiling platform integrating exosome isolation and targeted proteomic analysis is disclosed. This platform is capable of quantitative exosomal biomarker profiling directly from 30 μL plasma samples within approximately 100 minutes with markedly enhanced sensitivity and specificity. Identification of distinct subpopulation of patient-derived exosomes is demonstrated by probing surface proteins and multiparameter analyses of intravesicular biomarkers in the selected subpopulation. The expression of IGF-1R and its phosphorylation level in non-small cell lung cancer (NSCLC) patient plasma is assessed, as a non-invasive alternative to the conventional biopsy and immunohistochemistry. The microfluidic chip, which may be fabricated of a glass substrate and a layer of poly(dimethylsiloxane), can include a first capture chamber, a second capture chamber, a serpentine microchannel, a first microchannel, a second microchannel, a sample inlet, a buffer inlet, a bead inlet, at least a first connector channel, and a reagent inlet.
1. A method of diagnosis, or for aiding in diagnosis, or for monitoring treatment of a subject comprising processing a sample obtained or derived from the subject with a microfluidic chip comprising:
a first capture chamber configured to enable immunomagnetic isolation;
a second capture chamber configured to enable protein analysis;
a serpentine microchannel connecting the first capture chamber and the second capture chamber;
a first microchannel connecting the first capture chamber and the serpentine microchannel;
a second microchannel connecting the serpentine microchannel and the second capture chamber;
a sample inlet connected to the first capture chamber;
a buffer inlet connected to the first capture chamber;
a bead inlet;
at least a first connector channel connected to the bead inlet and the first microchannel, wherein the first connector channel is connected to the first microchannel upstream of the serpentine microchannel and downstream of the first capture chamber; and
a reagent inlet connected to the second microchannel upstream of the second capture chamber and downstream of the serpentine microchannel,
wherein the method comprises detecting a signal from a detectably labeled antibody, wherein the antibody is specifically bound to a protein marker that was present in exosomes in the sample obtained or derived from the subject, wherein the presence of the protein marker is positively correlated with a condition that the subject is at risk for developing, is suspected of having, or has been diagnosed with, wherein the signal from the detectably labeled antibody is generated in the second capture chamber, wherein the processing the sample comprises introducing the sample into the sample inlet, introducing antibodies specific for an exosome surface marker into the reagent inlet, wherein the antibodies are conjugated to magnetic beads, adding a buffer comprising 0.01% Tween 20 into the buffer inlet such that the buffer contacts the sample, capturing exosomes in the first capture chamber, lysing the exosomes such that that the surface proteins are released and are mixed with antibodies in the serpentine microchannel, magnetically capturing complexes comprising the antibodies and the exosome surface proteins in the second capture chamber, and detecting a signal from the antibodies to quantify the surface proteins, wherein the time from introducing the sample into the sample outlet to formation of the complexes comprising the antibodies so that the signal from the antibodies can be detected is less than 1.5 hours.
2. The method of claim 1 , wherein the first capture chamber and the second capture chamber are approximately 4 mm in diameter and are configured to each capture up to approximately 10 9 2.8 mm microbeads.
3. The method of claim 1 , wherein the first capture chamber is configured to isolate magnetic microbeads with bound exosomes from a fluid sample.
4. The method of claim 1 , further comprising a second connector channel connected to the bead inlet and the first microchannel, wherein the second connector channel is connected to the first microchannel upstream of the serpentine microchannel and downstream of the first capture chamber.
5. The method of claim 1 , wherein the first connector channel has dimensions configured to enable magnetic microbeads to pass there through.
6. The method of claim 1 , further comprising at least one syringe pump connected to one of the sample inlet, the buffer inlet, the bead inlet, or the reagent inlet, wherein the syringe pump is configured to have picoliter resolution.
7. The method of claim 1 , further comprising a magnet positioned opposite of a surface of the microfluidic chip.
8. The method of claim 1 , wherein the microfluidic chip is fabricated of a glass substrate and a layer of poly(dimethylsiloxane).
9. The method of claim 1 , wherein the serpentine microchannel has at least one surface that is hydrophilic.
10. The method of claim 1 , further comprising an outlet connected to the second capture chamber.
11. The method of claim 1 , further comprising a four syringe pump connected to the sample inlet, the buffer inlet, the bead inlet, and the reagent inlet.
12. The method of claim 1 , wherein the sample comprises plasma.
13. The method of claim 1 , wherein the protein marker is a cancer marker.