Dissolution-Enhanced Luminescent Bioassay Based on Inorganic Lanthanide Nanoparticles.

Conventional dissociation-enhanced lanthanide fluoroimmunoassays (DELFIA) using molecular probes suffer from a low labeling ratio of lanthanide ions (Ln3+) per biomolecule. Herein, we develop a unique bioassay based on the dissolution-enhanced luminescence of inorganic lanthanide nanoparticles (NPs). As a result of the highly concentrated Ln3+ ions in a single Ln3+ NP, an extremely high Ln3+ labeling ratio can be achieved, which amplifies significantly the luminescence signal and thus improves the detection sensitivity compared to DELFIA. Utilizing sub-10 nm NaEuF4 NPs as dissolution-enhanced luminescent nanoprobes, we demonstrate the successful in vitro detection of carcinoembryonic antigen (CEA, an important tumor marker) in human serum samples with a record-low detection limit of 0.1 pgmL1 (0.5 fm). This value is an improvement of approximately 3 orders of magnitude relative to that of DELFIA. The dissolution-enhanced luminescent bioassay shows great promise in versatile bioapplications, such as ultrasensitive and multiplexed in vitro detection of disease markers in clinical diagnosis. [ABSTRACT FROM AUTHOR]