Bioconjugates of Photon-Upconversion Nanoparticles as Background-Free Labels for Immunosensing and Imaging
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| Year of publication | 2025 |
| Type | Article in Proceedings |
| Conference | XXVIIIth Biochemistry Congress |
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| Description | Photon-upconversion nanoparticles (UCNPs) are lanthanide-doped nanocrystals that exhibit anti-Stokes luminescence, enabling their detection without optical background interferences. Therefore, conjugates of UCNPs with biorecognition molecules are well-suited as labels in immunochemical sensing and imaging. Our work explores different ways of modifying the UCNP surface and employs the conjugates to develop immunoassays for a wide range of analytes, from small molecules to bacteria. As part of our research on cancer biomarker detection, we developed a single-molecule immunoassay for prostate-specific antigen based on counting individual immunocomplexes under a wide-field epiluminescence microscope. This work was followed by transferring the assay from the surface of a microtiter plate to magnetic microparticles for sample preconcentration, and we are currently exploring advanced assay formats to increase the assay specificity and sensitivity. Furthermore, we employ the UCNP bioconjugates for high-contrast visualization of biomarkers on cancer cells. Due to the insignificant optical background and low non-specific interactions, the upconversion readout provides a superior signal-to-background ratio compared to the fluorescence-based detection. We are also exploring other readout types. For example, laser-induced breakdown spectroscopy detects individual elements in UCNPs, enhancing the multiplexing capabilities. |
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