Highly sensitive immunoassay for human cardiac troponin based on photon-upconversion nanoparticles
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| Year of publication | 2021 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | With 15.2 million deaths in 2016 and a rising trend, more people die annually suffering a heart attack than from any other cause or disease. There is only a limited time available from the onset of the symptoms of acute myocardial infarction (AMI) to lifesaving treatment. Cardiac troponin is the recommended marker in the early AMI diagnosis. The standard assays are based on electrochemiluminescence, chemiluminescence, or electrochemical detection. Even though reaching acceptable limits of detection (LOD), higher sensitivity is still necessary. To overcome the performance of current methods, we designed streptavidin-modified photon upconversion nanoparticles (SA-UCNP) based on a PEG linker and utilized them in upconversion immunoassays to detect cardiac troponin. We developed two assays; a microtiter plate-based upconversion immunoassay (ULISA) for sensitive laboratory diagnosis and a lateral-flow immunoassay (LFIA) for rapid detection. The PEG linker allowed reducing the non-specific interactions due to the steric hindrance and repulsion effects. For the ULISA, we chose a 2+2 assay configuration, with two monoclonal antibodies coated on the surface to capture the analyte, which was then detected by two biotinylated antibodies and SA-UCNPs. The LFIA was based on a 2+1 configuration, with one biotinylated antibody for the detection; biotinylated BSA was used for the control line. We achieved LOD of 4.7 pg/mL for the ULISA and 13.8 ng/mL for LFIA, respectively. Furthermore, we demonstrated that the ULISA is a feasible alternative to existing assays, with LOD in the serum of 15.5 pg/mL, two times lower than the troponin concentration in healthy patients. |
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