Detection of pathogenic bacteria using half-fragments antibody immobilized Fe3O4@FeSe2 core-shell nanoparticles

Abstract

Iron diselenide(FeSe2)-coated Fe3O4 magnetic nanoclusters (MNCs) were synthesized to detect pathogenic bacteria. MNCs were hydrothermally synthesized and coated with FeSe2 via co-reduction method. Hydrazine hydrate reduced Fe3O4 and Se powder to Fe2+ and Se22-, respectively. Co-reduction enabled FeSe2 shell to grow directly on the surface of MNCs. The stability and magnetization of Fe3O4@FeSe2 nanoparticles were controlled by addition of a small amount of FeCl3. FeSe2 shell enhanced the bacterial capture efficiency due to the favorable orientation of half fragments of anti-Escherichia coli antibodies through selenosulfide bond and the large surface area of the particles. As a results, the capture efficiency of Fe3O4@FeSe2 nanoparticles via selenosulfide-based immobilization of antibodies was two times higher than that of Fe3O4 nanoparticles through amide-based immobilization of antibodies.