Magnetic Bead-based Exosome Extraction: A Technique to Isolate Specific Exosomes from Biofluids

Exosomes are extracellular vesicular structures secreted by cells into biofluids. To capture specific exosomes from biofluids, begin by taking streptavidin-coated magnetic beads in a tube.

To this tube, add biotinylated anti-human antibodies. Biotin present on the antibodies has a high affinity for streptavidin present on the magnetic beads. This results in the conjugation of the antibodies with the magnetic beads.

Next, add a protein-rich blocking solution to the tube containing the antibody-labeled magnetic beads. The proteins in the blocking solution bind to the free sites on the magnetic beads and increase specificity of exosome binding.

Now, supplement the tube with a sample biofluid rich in exosomes. Incubate the tube with agitation. The exosomes in the biofluid display specific surface receptors, which help them bind to the antibodies attached to the surface of magnetic beads.

Next, place the tube in a magnetic field. Under the influence of magnetic field, the exosome-bound magnetic beads attach to the surface of the tube. Then, using a micropipette, aspirate the remaining biofluid from the tube.

Finally, remove the tube from the magnetic field and add a suitable buffer to elute the exosome-bound beads. These exosome-bound beads can be used for further downstream analysis.