SERS-fluorescence dual-mode aptasensor based on Hollow mesoporous silica combined with gating mechanism for the detection of Aflatoxin B1

Aflatoxin B1 (AFB1) is a typical toxin found in maize, leaving severe threats to human health and livestock. A dual-signal SERS-fluorescence aptasensor was constructed to detect Aflatoxin B1. Hollow mesoporous silica nanoparticles functionalized with amino groups (AHMSN) were designed as carriers for the dual-signal molecule Rh6G. The aptamer, adsorbed onto the surface of AHMSN Rh6G via electrostatic interactions, acted as a “gate” to block the release of Rh6G. Simultaneously, the noble metal nanocomposite Au@Ag NRs was developed as the SERS substrate. The strong and selective interaction between the aptamer and AFB1 led to the release of Rh6G, resulting in SERS and fluorescence signals that were positively correlated with the concentration of AFB1. The LOD of SERS and fluorescence were 0.0092 ng/mL and 0.0050 ng/mL, respectively. At the same time, the sensor demonstrated good accuracy in detecting AFB1 in various maize meal/oil samples, showing strong practical applicability. This research developed a highly specific and sensitive dual-mode detection method for AFB1, circumventing the need for aptamer chemical modification or the incorporation of complementary strands. This approach presents a simplified, cost-efficient, and versatile strategy for AFB1 detection.