Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10234995 | New Biotechnology | 2015 | 6 Pages |
Abstract
In this paper we present a simple method to quantify aggregates of 200Â nm magnetic particles. This method relies on the optical and magnetic anisotropy of particle aggregates, whereas dispersed particles are optically isotropic. We orientate aggregates by applying short pulses of a magnetic field, and we measure optical density variation directly linked to this reorientation. By computing the scattering efficiency of doublets and singlets, we demonstrate the absolute quantification of a few % of doublets in a well dispersed suspension. More generally, these optical variations are related to the aggregation state of the sample. This method can be easily applied to an agglutination assay, where target proteins induce aggregation of colloidal particles. By observing only aligned clusters, we increase sensitivity and we reduce the background noise as compared to a classical agglutination assay: we obtain a detection limit on the C-reactive protein of less than 3Â pM for a total assay time of 10Â min.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Bioengineering
Authors
Donatien Ramiandrisoa, Elodie Brient-Litzler, Aurélien Daynes, Eric Compain, Jérôme Bibette, Jean Baudry,