Methods and microfluidic devices for chiroptical detection and mutation analysis of cancer-associated extracellular vesicles

A method of detecting a target bioactive analyte in a biological fluid sample obtained from a subject, the method comprising:

• passing a biological fluid sample through a microfluidic channel comprising at least one surface having a plurality of chiral nanoparticles disposed thereon and directing circularly polarized light at the microfluidic channel while the biological fluid sample is disposed therein to measure a first level of at least one of magnitude of circular dichroism or peak wavelength, wherein the plurality of chiral nanoparticles each comprises a light-absorbing material selected from the group consisting of:
• gold, silver, copper, nickel, iron, carbon, platinum, silicon, CdTe, CdSe, CdS, HgTe, HgSe, HgS, PbTe, PbSe, PbS, MoS2, FeS2, FeS, FeSe, and combinations thereof, and a targeting ligand that is capable of binding to a bioactive target analyte optionally present in the biological fluid sample;
• and
• comparing the first level of at least one of magnitude of circular dichroism or peak wavelength to a baseline level of at least one of magnitude of circular dichroism or peak wavelength in the microfluidic channel in the absence of the biological fluid sample, wherein a difference between the first level and the baseline level indicates a presence of the bioactive target analyte that indicates a presence of cancerous cells or mutated proteins in the biological fluid sample.

A method for forming a microfluidic device for detecting a bioactive target analyte in a biological fluid sample obtained from a subject, the method comprising:

• applying a first charged material having a first polarity to at least one surface of a microfluidic channel on a substrate having a second polarity opposite to the first polarity;
• applying a second charged material having the second polarity over the first charged material in a layer-by-layer process on the at least one surface, wherein the first charged material and the second charged material are distinct from one another and define a layered coating;
• applying a plurality of chiral nanoparticles over the layered coating, so that the plurality of chiral nanoparticles are exposed to the microfluidic channel and each comprises a light-absorbing material selected from the group consisting of:
• gold, silver, copper, nickel, iron, carbon, platinum, silicon, CdTe, CdSe, CdS, HgTe, HgSe, HgS, PbTe, PbSe, PbS, MoS2, FeS2, FeS, FeSe, and combinations thereof;
• and
• functionalizing the plurality of chiral nanoparticles and associating each nanoparticle of the plurality with a targeting ligand that is capable of binding to the bioactive target analyte in the biological fluid sample, wherein the bioactive target analyte indicates a presence of cancerous cells or mutated proteins in the biological fluid sample.