Development of novel FRET aptasensor based on the quenching ability of iron oxide-gold nanostars for the detection of aflatoxin M1

Detecting Aflatoxin M1 (AFM1) in food products is crucial due to its high toxicity and health risks. This study introduced a fluorescence donor material using Rhodamine-B-Isothiocyanate (RBITC)-doped silica nanoparticles (RDSN) combined with iron oxide‑gold nanostars (IOGNS) as a quencher. The composite aptasensor (RDSN/IOGNS) served as a Förster Resonance Energy Transfer (FRET) nanoprobe for sensitive and selective AFM1 detection. The fluorescence of aptamer-conjugated RDSN (apt-RDSN) was effectively quenched by complementary DNA-conjugated IOGNS (cDNA-IOGNS). Upon AFM1 introduction, apt-RDSN dissociated from the IOGNS surface, restoring the fluorescence signal. The fluorescence intensity correlated linearly with AFM1 concentration, achieving a detection limit of 0.15 ng/mL. Compared to conventional enzyme-linked immunosorbent assay (ELISA), this FRET aptasensor showed excellent recovery rate and relative standard deviation (RSD) in milk samples, highlighting its potential for practical AFM1 detection applications.