Colloidal particles are routinely used in a wide variety of medical applications, including the capture of bioanalytes, assisting in the sorting of cells and the delivery of drugs and genes. A recent extension of the use of colloids is in acoustofluidic systems, where standing pressure waves redirect particles under continuous flow. We have recently developed a class of colloidal particles with unique acoustic properties that allows them to rapidly separate from cells in an acoustic standing wave. These elastomeric particles focus along the pressure antinodes of a standing wave (due to their negative acoustic contrast factors, <i>Φ</i>), whereas cells focus along the node(s). Using these particles, we have developed a simple biodetection technology that enables the capture, separation and enrichment of biomarkers, which can be useful for the detection of exceedingly rare biomarkers. This technology is enabled by the co-aggregation of genetically engineered polypeptides (i.e., elastin-like polypeptides, ELPs), which display lower critical solution temperature (LCST) phase behavior. By adding soluble ELPs with an antibody-binding domain (below their LCST) to blood samples along with elastomeric particles with ELPs conjugated to their surface, diffusion facilitates the rapid capture of biomarkers. Raising the temperature of the suspension (i.e., to 40°C) results in rapid precipitation on the surface of the particles. Finally, by injecting this suspension into an acoustofluidic device, bound biomarkers are isolated from blood cells for off-chip quantification using flow cytometry or enriched by releasing the biomarkers via reducing the temperature. This method of biomarker enrichment provides the potential to discover rare biomarkers from complex biological fluids for more sensitive and potentially faster diagnosis.

Peptide-conjugated elastomeric particles for acoustic isolation of biomarkers from whole blood

251st National Meeting (2016)

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