Rapid and Ultrasensitive Fluorescence Sensing Platform Based on Nanometer-Sized Metal–Organic Frameworks for Transgenic CaMV 35S Promoter Detection

Abstract

Rapid and sensitive identification of genetically modified organisms (GMOs) is urgent for food safety and people health. Herein, a rapid and ultrasensitive fluorescence sensing platform is developed based on the single-strand DNA-labeled FAM dye (FAM-ssDNA) and nanometer-sized Fe-metal–organic framework (Fe-MOF), Fe-MIL-88. Fe-MIL-88 possesses a large specific surface area, remarkable preferential combining capacity with ssDNA versus dsDNA, and great quenching ability. FAM-ssDNA probes are elaborately designed as facile fluorescent probes to be fully complementary with the target of cauliflower mosaic virus 35S promoter (CaMV 35S), which can be absorbed to the surface of Fe-MIL-88 through π–π stacking and electrostatic interaction. The results indicate that the quenching ability of Fe-MIL-88 is attributed to the combination of photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) processes. Benefiting from the distinguishable ability of Fe-MIL-88, the fluorescent biosensor exhibits a satisfactory linear range from 5 pM to 50 nM and a low limit of detection (LOD) down to 0.184 pM. Also, the operation time was less than 1 h. Furthermore, the sensor also performs well in the anti-interference test and real sample test. Importantly, the sensing platform is equipped with easier operation without any complicated and difficult immobilization steps. Therefore, the sensor owns cheering potential for the detection of GMOs.