More than magnetic isolation: Dynabeads as strong Raman reporters towards simultaneous capture and identification of targets
Dynabeads are superparamagnetic particles used for immunomagnetic purification of cells and biomolecules. Post-capture, however, target identification relies on tedious culturing, fluorescence staining and/or target amplification. Raman spectroscopy presents a rapid detection alternative, but curren...
Saved in:
Main Authors | , , , , , |
---|---|
Format | Journal Article |
Language | English |
Published |
11.05.2023
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Dynabeads are superparamagnetic particles used for immunomagnetic
purification of cells and biomolecules. Post-capture, however, target
identification relies on tedious culturing, fluorescence staining and/or target
amplification. Raman spectroscopy presents a rapid detection alternative, but
current implementations target cells themselves with weak Raman signals. We
present antibody-coated Dynabeads as strong Raman reporter labels whose effect
can be considered a Raman parallel of immunofluorescent probes. Recent
developments in techniques for separating target-bound Dynabeads from unbound
Dynabeads makes such an implementation feasible. We deploy Dynabeads
anti-Salmonella to bind and identify Salmonella enterica, a major foodborne
pathogen. Dynabeads present signature peaks at 1000 and 1600 1/cm from
aliphatic and aromatic C-C stretching of polystyrene, and 1350 1/cm and 1600
1/cm from amide, alpha-helix and beta-sheet of antibody coatings of the Fe2O3
core, confirmed with electron dispersive X-ray (EDX) imaging. Their Raman
signature can be measured in dry and liquid samples even at single shot ~30 x
30-micrometer area imaging using 0.5 s, 7 mW laser acquisition with single and
clustered beads providing a 44- and 68-fold larger Raman intensity compared to
signature from cells. Higher polystyrene and antibody content in clusters
yields to the larger signal intensity and conjugation to bacteria strengthens
clustering as a bacterium can bind to more than one bead as observed via
transmission electron microscopy (TEM). Our findings shed light on the
intrinsic Raman reporter nature of Dynabeads, demonstrating their dual function
for target isolation and detection without additional sample preparation,
staining, or unique plasmonic substrate engineering, advancing their
applications in heterogeneous samples like food, water, and blood. |
---|---|
DOI: | 10.48550/arxiv.2305.07199 |