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Updated: Feb 11, 2026

Automated System for Single Molecule Fluorescence Measurements of Surface-immobilized Biomolecules
Published on: November 2, 2009
Single-Molecule Flow Platform for the Quantification of Biomolecules Attached to Single Nanoparticles
Seung-Ryoung Jung1, Rui Han1, Wei Sun1
1Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States.
Abstract:
We describe here a flow platform for quantifying the number of biomolecules on individual fluorescent nanoparticles. The platform combines line-confocal fluorescence detection with near nanoscale channels (1-2 μm in width and height) to achieve high single-molecule detection sensitivity and throughput. The number of biomolecules present on each nanoparticle was determined by deconvolving the fluorescence intensity distribution of single-nanoparticle-biomolecule complexes with the intensity distribution of single biomolecules. We demonstrate this approach by quantifying the number of streptavidins on individual semiconducting polymer dots (Pdots); streptavidin was rendered fluorescent using biotin-Alexa647. This flow platform has high-throughput (hundreds to thousands of nanoparticles detected per second) and requires minute amounts of sample (∼5 μL at a dilute concentration of 10 pM). This measurement method is an additional tool for characterizing synthetic or biological nanoparticles.
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