Magnetic metal-organic frameworks-based ratiometric SERS aptasensor for sensitive detection of patulin in apples

Patulin (PAT), a major contaminant in apples, poses a considerable food safety risk, necessitating a rapid, sensitive and reliable detection method. This study developed a novel magnetic metal-organic frameworks (MOFs)-based ratiometric surface-enhanced Raman scattering (SERS) aptasensor. The sensor consists of magnetic MOFs loaded with 4-Mercaptobenzoic acid (4-MBA) internal labeled Au-MBA@Ag as the SERS substrate, and gold nanorods (AuNRs) modified with Rhodamine 6G and aptamers as capture probes. This strategy enhances sensitivity through magnetic separation and abundant SERS hotspots provided by the magnetic MOF nanocomposites. The SERS intensity ratio showed a negative correlation with PAT concentrations from 0.01 to 100 ng/mL, with a LOD of 0.0465 ng/mL. Moreover, the aptasensor achieved 95.90 % similar to 105.83 % recoveries in apple samples, indicating high accuracy and anti-interference capability. The excellent sensing performance demonstrates great potential of the SERS nanosensor for mycotoxin detection in actual food matrices.