Quantitative Single-Molecule Electrochemiluminescence Bioassay

A single-molecule electrochemiluminescence bioassay is developed here which allows imaging and direct quantification of single biomolecules. Imaging single biomolecules is realized by localizing the electrochemiluminescence events of the labeled molecules. Such an imaging system allows mapping the spatial distribution of biomolecules with electrochemiluminescence and contains quantitative single-molecule insights. We further quantify biomolecules by spatiotemporally merging the repeated reactions at one molecule site and then counting the clustered molecules. The proposed single-molecule electrochemiluminescence bioassay is used to detect carcinoembryonic antigen, showing a limit of detection of 67 attomole concentration which is 10 000 times better than conventional electrochemiluminescence bioassays. This spatial resolution and sensitivity enable single-molecule electrochemiluminescence bioassay a new toolbox for both specific bioimaging and ultrasensitive quantitative analysis.

Automated summary

A single-molecule electrochemiluminescence bioassay is developed for imaging and direct quantification of single biomolecules. This assay localizes the electrochemiluminescence events and allows mapping of biomolecule distribution. By merging repeated reactions and counting clustered molecules, biomolecules can be quantified. The developed bioassay shows a detection limit of 67 attomole concentration and represents a new tool for specific bioimaging and ultrasensitive quantitative analysis.