Surface-Complexed Zinc Ferrite Magnetofluorescent Nanoparticles for Killing Cancer Cells and Single-Particle-Level Cellular Imaging

The fabrication of novel magnetofluorescent nanoparticles (NPs) by complexation of zinc ions present on the surface of a zinc ferrite nanoparticle (ZnFe₂O₄ NP) with 8-hydroxy-2-quinolinecarboxaldehyde (HQCald) is reported. The as-prepared HQCald-complexed ZnFe₂O₄ NPs showed good quantum yield (3.62%), high photostability, considerable excited-state lifetime (5.31 ns), and high saturation magnetization (12.7 emu/g). These magnetofluorescent NPs demonstrated bioimaging capability at both the ensemble- and single-particle levels and in vitro magnetic targeting. Moreover, the pronounced antiproliferative efficacy of these NPs against cancer cells, with appropriate targeting strategies, can lead to potential cancer theranostics.