Aptamers-functionalized nanoscale MOFs for saxitoxin and tetrodotoxin sensing in sea foods through FRET

Saxitoxin (STX) and tetrodotoxin (TTX) are widely distributed and extremely harmful marine toxins, it is certainly worth to spend effort to develop facile methods to detect them in sea food for human safety. In this work, two nano-sensors were developed by combining with two zirconium fluorescence Nanoscale metal-organic frameworks (NMOFs) with two emissions and TAMRA-labelled aptamers for STX and TTX sensing, respectively. The recognition of STX and TTX by these nano-sensors could change the structure of aptamer, which caused the blue or green emissions from NMOFs (energy donor) decreased while red emission from TAMRA-labelled aptamers (energy acceptor) increased owing to fluorescence resonance energy transfer (FRET) effect. Based on this strategy, NMOFs-Aptasensor 1 and NMOFs-Aptasensor 2 were developed for the ratiometric detection, with detection limits of 1.17 nM and 3.07 nM for STX and TTX, respectively. Moreover, NMOFs-Aptasensors displayed significant stability, pH-independence, selectivity and NMOFs-Aptasensors were successfully applied in shellfish sample for toxin sensing.