Nanoscale fluoro-immunoassays with lanthanide oxide nanoparticles

Abstract

The use of polystyrene nanoparticles with europium chelate has been demonstrated as fluorescent reporters in an immunoassay for atrazine. The limit of detection with the nanoparticles was similar to that achieved with a conventional ELISA. It was shown that as the particle size decreased the time required for binding decreased and the sensitivity of the assay increased. This suggests that the use of smaller particles would greatly speed up the reaction and simultaneously increase sensitivity. However, the detection system used sets limits to the particle size as well. There is clearly a point where our detection system would not be sensitive enough to detect the emission from small particles. Therefore, a highly sensitive excitation/detection system needs to be developed to fully utilize the kinetic advantage from small particle size.