ac3029344_si_001.pdf (4.51 MB)
Download fileElastomeric Negative Acoustic Contrast Particles for Affinity Capture Assays
journal contribution
posted on 2016-02-19, 22:08 authored by Kevin
W. Cushing, Menake E. Piyasena, Nick J. Carroll, Gian C. Maestas, Beth Ann López, Bruce S. Edwards, Steven W. Graves, Gabriel P. LópezThis report describes the development of elastomeric
capture microparticles
(ECμPs) and their use with acoustophoretic separation to perform
microparticle assays via flow cytometry.We have developed simple methods
to form ECμPs by cross-linking droplets of common commercially
available silicone precursors in suspension followed by surface functionalization
with biomolecular recognition reagents. The ECμPs are compressible
particles that exhibit negative acoustic contrast in ultrasound when
suspended in aqueous media, blood serum, or diluted blood. In this
study, these particles have been functionalized with antibodies to
bind prostate specific antigen and immunoglobulin (IgG). Specific
separation of the ECμPs from blood cells is achieved by flowing
them through a microfluidic acoustophoretic device that uses an ultrasonic
standing wave to align the blood cells, which exhibit positive acoustic
contrast, at a node in the acoustic pressure distribution while aligning
the negative acoustic contrast ECμPs at the antinodes. Laminar
flow of the separated particles to downstream collection ports allows
for collection of the separated negative contrast (ECμPs) and
positive contrast particles (cells). Separated ECμPs were analyzed
via flow cytometry to demonstrate nanomolar detection for prostate
specific antigen in aqueous buffer and picomolar detection for IgG
in plasma and diluted blood samples. This approach has potential applications
in the development of rapid assays that detect the presence of low
concentrations of biomarkers in a number of biological sample types.