Mickert, Matthias J. and Farka, Zdenek and Kostiv, Uliana and Hlavacek, Antonin and Horak, Daniel and Skladal, Petr and Gorris, Hans H. (2019) Measurement of Sub-femtomolar Concentrations of Prostate-Specific Antigen through Single-Molecule Counting with an Upconversion-Linked Immunosorbent Assay. ANALYTICAL CHEMISTRY, 91 (15). pp. 9435-9441. ISSN 0003-2700, 1520-6882
Full text not available from this repository. (Request a copy)Abstract
Single-molecule (digital) immunoassays provide the ability to detect much lower protein concentrations than conventional immunoassays. As photon-upconversion nanoparticles (UCNPs) can be detected without optical background interference, they are excellent labels for so-called single-molecule upconversion-linked immunosorbent assays (ULISAs). We have introduced a UCNP label design based on streptavidin-PEG-neridronate and a two-step detection scheme involving a biotinylated antibody that efficiently reduces nonspecific binding on microtiter plates. In a microtiter plate immunoassay, individual sandwich immune complexes of the cancer marker prostate-specific antigen (PSA) are detected and counted by wide-field epiluminescence microscopy (digital readout). The digital detection is 16X more sensitive than the respective analogue readout and thus expands the limit of detection to the sub-femtomolar concentration range (LOD: 23 fg mL(-1), 800 aM). The single molecule ULISA shows excellent correlation with an electrochemiluminescence reference method. Although the analogue readout can routinely measure PSA concentrations in human serum samples, very low concentrations have to be monitored after radical prostatectomy. Combining the digital and analogue readout covers a dynamic range of more than 3 orders of magnitude in a single experiment.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOTON-UPCONVERTING NANOPARTICLES; ENHANCED RAMAN-SCATTERING; SENSITIVE DETECTION; IMMUNOASSAY; AMPLIFICATION; SHELL; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 01 Apr 2020 05:04 |
| Last Modified: | 01 Apr 2020 05:04 |
| URI: | https://pred.uni-regensburg.de/id/eprint/26451 |
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