Sandwich immunoassay devices using antibodies specific to the exosomes containing target analytes

A lateral flow assay device, comprising:

• a plurality of test strips configured to receive a quantity of fluid comprising a quantity of exosomes and detect a presence of a target analyte on a surface of the exosomes, wherein the surface of each exosome comprises one or more tetraspanin proteins, and wherein the target analyte is a marker of a malignancy that attaches to the surface of the exosomes;
• wherein each test strip comprises:
• a conjugate pad;
• and
• a membrane fluidly connected to the conjugate pad of the corresponding test strip,
• wherein the conjugate pad of each test strip contains binding reagents to a plurality of types of tetraspanin protein, wherein the binding reagents are conjugated with a label, wherein the binding reagent to each type of tetraspanin protein binds with the corresponding type of tetraspanin protein on a surface of an exosome and forms an immunocomplex comprising the exosome,
• wherein the conjugate pad of each test strip is configured to receive the fluid after a start of a test and move the fluid by capillary action,
• wherein the membrane of each strip is configured to move the fluid by capillary action, and
• wherein the membrane of each strip comprises a test line comprising a quantity of an immobilized binding reagent to the target analyte, and wherein the immobilized binding reagent to the target analyte binds to the target analyte that is attached to the surface of the exosome in the immunocomplex comprising the exosome.