Highly luminescent organic nanoparticles were formed by embedding hydrophobic and hydrophilic (CdSe)ZnS quantum dots with core/shell structure into ethyl cellulose nanoparticles. The nanoparticles were prepared from oil-in-water nanoemulsions by a phase inversion process at constant temperature, followed by a solvent evaporation. The obtained fluorescent ethyl cellulose nanoparticles were functionalized by immobilization of a specific antibody, and applied in rapid agglutination test for detection of Yersinia pestis F1-antigen. © 2009 Elsevier B.V. All rights reserved.