Microarray-based identification of lectins for the purification of human urinary extracellular vesicles directly from urine samples.

As cellular-derived vesicles largely maintain the biomolecule composition of their original tissue, exosomes, which are found in nearly all body fluids, have enormous potential as clinical disease markers. A major bottleneck in the development of exosome-based diagnostic assays is the challenging purification of these vesicles; this requires time-consuming and instrument-based procedures. We employed lectin arrays to identify potential lectins as probes for affinity-based isolation of exosomes from the urinary matrix. We found three lectins that showed specific interactions to vesicles and no (or only residual) interaction with matrix proteins. Based on these findings a bead-based method for lectin-based isolation of exosomes from urine was developed as a sample preparation step for exosome-based biomarker research.