Simultaneous determination of two phosphorylated p53 proteins in SCC-7 cells by an ICP-MS immunoassay using apoferritin-templated europium(III) and lutetium(III) phosphate nanoparticles as labels.

Author(s) Yin, X.; Chen, B.; He, M.; Hu, B.
Journal Mikrochim Acta
Date Published 2019 Jun 11

Phosphorylated p53 proteins are biomarkers with clinical utility for early diagnosis of cancer, but difficult to quantify. An inductively coupled plasma mass spectrometry (ICP-MS) based immunoassay is described here that uses uniform lanthanide nanoparticles (NPs) as elemental tags for the simultaneous determination of two phosphorylated p53 proteins. Apoferritin templated europium (Eu) phosphate (AFEP) NPs and apoferritin templated lutetium (Lu) phosphate (AFLP) NPs with 8 nm in diameter were used to label two phosphorylated p53 proteins at serine 15 and serine 392 sites (p-p53 and p-p53), respectively. The assay has a sandwich format, and p-p53 and p-p53 were first captured and then recognized by AFEP and AFLP NPs labelled antibodies, respectively. The Eu and Lu were then released from the immune complexes under acidic condition for ICP-MS measurement. The limits of detection for p-p53 and p-p53 are 200 and 20 pg·mL, with linear ranges of 0.5-20 and 0.05-20 ng·mL, respectively. The method was further applied to study the response of p-p53 and p-p53 in SCC-7 cells exposed to the natural carcinogen arsenite. A significant up-regulation of p-p53 and p-p53 can be observed when cells were exposed to arsenite at 5 μmol·L level for 24 h. Graphical abstract Schematic presentation of the ICP-MS immunoassay using apoferritin templated europium (III) and lutetium (III) phosphate nanoparticles as labels for the simultaneous determination of two phosphorylated p53 proteins. Europium (Eu) phosphate nanoparticles (blue) and lutetium (Lu) phosphate nanoparticles (pink) were synthesized in the size-restricted cavity of apoferritin. They were further coupled with antibodies to prepare Eu and Lu labelled probes for p-p53 (blue) and p-p53 (pink), respectively. After formation of a a sandwich, the labelled Eu and Lu were dissociated in acid and then introduced to ICP-MS for the simultaneous determination of two phosphorylated p53 proteins p-p53 (blue) and p-p53 (pink).

DOI 10.1007/s00604-019-3540-4
ISSN 1436-5073
Citation Mikrochim Acta. 2019;186(7):424.

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