Time-resolved luminescent biodetection of biotin in infant formula based on lanthanide-doped LiLuF4 nanoparticles

Biotin, as a key nutrition fortifier in infant formula, is of vital significance for guaranteeing the healthy growth of infants and young children. The accurate detection of biotin has therefore become a crucial priority for quality assurance in infant formula. However, the current bioassay techniques encounter a series of limitations such as cumbersome procedures and low sensitivity. Herein, we develop a sensitive time-resolved fluorescence resonance energy transfer (TR-FRET) nanoprobe by employing LiLuF 4 : Ce/Tb nanoparticles (NPs) as energy donors for biotin detection. By taking advantage of the distinctive millisecond-range photoluminescence of the NPs, the short-lived background autofluorescence can be completely eliminated, which enables the sensitive detection of biotin in infant formula within a range of 0−6104 pM and a detection limit down to 0.84 pM (0.21 pg mL −1 ). This value indicates 2−4 orders of magnitude improvement over conventional bioassay methods. The proposed TR-FRET biosensor is independent of expensive instruments and can be fully compatible with commercial microplate readers. Specifically, the homogeneous assay design enables rapid, user-friendly analysis, completing the entire detection process within 20 minutes. These findings offer new opportunities towards rapid and sensitive detection of biotin in infant nutrition products, thereby demonstrating the great potential of lanthanide nanoprobes in food safety monitoring applications.