PHOTON-UPCONVERSION NANOPARTICLES FOR SINGLE-MOLECULE IMMUNOSENSING OF CANCER BIOMARKERS AND BACTERIA

1 FARKA Zdeněk
Co-authors:
2 Mickert Matthias J. 3 Hlaváček Antonín 1 Poláchová Veronika 4 Kostiv Uliana 1 Pastucha Matěj 4 Horák Daniel 2 Gorris Hans H. 1 Skládal Petr
Institutions:
1 CEITEC MU, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic, EU, farka@mail.muni.cz
2 Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93053 Regensburg, Germany, EU
3 Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00 Brno, Czech Republic, EU
4 Institute of Macromolecular Chemistry of the Czech Academy of Sciences, 162 06 Prague, Czech Republic, EU
Conference:
11th International Conference on Nanomaterials - Research & Application, Hotel Voronez I, Brno, Czech Republic, EU, October 16th - 18th 2019
Proceedings:
Proceedings 11th International Conference on Nanomaterials - Research & Application
Pages:
311-316
ISBN:
978-80-87294-95-6
ISSN:
2694-930X
Published:
1st April 2020
Proceedings of the conference have been sent to Web of Science and Scopus for evaluation and potential indexing.
Metrics:
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Abstract

The recent progress in the field of immunoassays has been driven by introduction of various kinds of nanomaterials. In particular, photon-upconversion nanoparticles (UCNPs) proved to be excellent immunoassay labels due to their ability to emit light of shorter wavelengths under near-infrared excitation (anti-Stokes emission), which prevents autofluorescence, minimizes light scattering, and thus reduces the optical background interference. These unique photoluminescent properties allow counting of individual biomolecules labeled with UCNPs by conventional wide-field epiluminescence microscopy and enable the development of single-molecule (digital) immunoassays. We have introduced a novel label based on UCNPs conjugated with streptavidin via poly(ethylene glycol) and applied it in a digital upconversion-linked immunosorbent assay (ULISA) for the detection of a cancer biomarker prostate specific antigen (PSA). The digital readout based on counting of individual immunocomplexes improved the sensitivity 16× compared to conventional analog readout and allowed to reach a limit of detection (LOD) of 23 fg·mL−1 (800 aM). Human serum samples were successfully analyzed achieving an excellent correlation with electrochemiluminescence reference method. The conjugates of UCNPs with streptavidin are also suitable for the detection of pathogenic bacterium Melissococcus plutonius, the causative agent of honeybee disease European foulbrood. The ULISA assay provided an LOD of 340 CFU·mL−1 and successfully analyzed real samples of bees, larvae and bottom hive debris. Due to the high reliability and relatively simple detection scheme, the digital ULISA can pave the way for a new generation of digital immunoassays with a strong potential for commercialization.

Keywords: Single-molecule detection, photon-upconversion nanoparticle, bioconjugation, digital upconversion-linked immunosorbent assay
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