Satellite nanostructures composed of CdTe quantum dots and DTNB-labeled AuNPs used for SERS-fluorescence dual-signal detection of AFB₁

Herein, a surface-enhanced Raman scattering (SERS) and fluorescence dual-signal aptasensor has been developed for aflatoxin B₁ (AFB₁) detection. Fluorescence signal source CdTe quantum dots were decorated on the outer of silica nanoparticles and further functionalized with AFB₁ aptamer. Raman reporter molecules DTNB were decorated on the surface of gold nanoparticles (AuNPs) together with the aptamer complementary chains. The two parts of nanomaterials were combined by the base complementary pairing principle, to form satellite nanostructures with high SERS and low fluorescence signals following LSPR and FRET effect. The addition of AFB₁ led to the shedding of AuNPs due to the higher sensitivity of the aptamer towards the target and resulting in recovered fluorescence and decreased SERS signals. The developed method showed a linear relationship in the range of 10⁻⁴-10³ ng/mL, with detection limit of 0.094 pg/mL. This technology had strong application prospects due to simplicity of operation and high accuracy.