Publication details

Photon-upconversion nanoparticles for single-molecule immunoassays

Investor logo
Investor logo

FARKA Zdeněk MICKERT Matthias Jürgen HLAVÁČEK Antonín SKLÁDAL Petr GORRIS Hans-Heiner

Year of publication 2021
Type Conference abstract
MU Faculty or unit

Faculty of Science

Description The recent progress in the field of immunoassays has been enabled by the development of various kinds of nanomaterials. In particular, photon-upconversion nanoparticles (UCNPs) proved to be excellent labels due to their ability to emit shorter wavelength light under near-infrared excitation (anti-Stokes emission), which prevents autofluorescence, minimizes light scattering, and thus reduces the optical background. These unique properties enabled imaging of single UCNPs by wide-field epiluminescence microscopy and allowed development of single-molecule (digital) immunoassays. We have synthesized conjugates of polyethylene glycol-coated UCNPs with streptavidin and applied them as a label for the detection of cancer biomarker prostate specific antigen (PSA). The detection was based on counting of individual sandwich immunocomplexes under the wide-field microscope. The noise-surpassing digital readout (particle counting) resulted in 20× higher sensitivity than the analog readout (output light intensity) and provided a detection limit of 23 fg mL-1 (800 aM) in 25% human serum. The conjugates of UCNPs with streptavidin are also useful as a label for the detection of bacterial pathogens. We have developed an immunoassay for the detection of causative agent of European foulbrood, bacterium Melissococcus plutonius. The assay provided a limit of detection of 340 CFU mL-1 and its practical applicability was verified by the analysis of real samples of bees, larvae and bottom hive debris.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.

More info