Fabrication of an activatable hybrid persistent luminescence nanoprobe for background-free bioimaging-guided investigation of food-borne aflatoxin in vivo

The development of in situ and real-time analytical methods for specifically probing food-borne hazardous substances is promising for clarifying their harmful behaviors and related disease mechanisms inside the living body through in situ investigation of their in vivo behaviors. Herein, optical nanoimaging with the ability of in situ non-damage detection and real-time monitoring was introduced for specific recognition of aflatoxin in cellular levels and in vivo via the fluorescence resonance energy transfer (FRET) protocol. Persistent luminescence nanophosphors (PLNPs) with distinct advantages of improved sensitivity and signal-to-noise ratio were employed in in vivo bioimaging as photoluminescence nanoprobes, while copper sulfide nanoparticles were utilized as the quencher. Due to their long-lasting afterglow, PLNPs do not require external illumination before imaging, effectively eliminating the scattering light and autofluorescence from the biological matrix that can occur during in situ excitation. The proposed FRET imaging assay achieved high sensitivity and specificity as well as improved imaging resolution for the target aflatoxin present in vivo. This study will provide insights towards advanced methodology for the applications of bioimaging in food safety, and could potentially provide an advisory roadmap for bioimaging-guided exploration and mediation of food-borne hazards to human health.