A split aptamers-based sandwich-type colorimetric aptasensor for the simultaneous detection of diarrhetic shellfish toxins

Poisoning incidents in marine foods caused by diarrhetic shellfish toxins (DSTs) pose a severe threat to public health. Therefore, developing novel technologies capable of simultaneously detecting DSTs is of critical importance for ensuring marine food safety. Here, a split aptamers-based sandwich-type colorimetric aptasensor (STCA) based on the principle of sandwich enzyme-linked immunosorbent assay was proposed for the simultaneous detection of three DSTs, i.e., okadaic acid, dinophysistoxin-1 and dinophysistoxin-2. STCA employs split aptamers as recognition elements instead of conventional antibodies, significantly reducing detection cost. A pair of split aptamers that function as capture probe and detection probe, respectively, form a specific sandwich structure (capture probe-DSTs-detection probe) in the presence of DSTs, enabling quantitative analysis via a colorimetric system. Within the concentration range of 0.01 ng/mL–100.00 ng/mL, STCA achieved a limit of detection as low as 0.003680 ng/mL. Moreover, the analysis with spiked shellfish samples showed that STCA's recovery rates ranged from 89.4% to 104.6%, indicating its excellent potential for DSTs screening. This work provides a promising alternative method for the preliminary screening and simultaneous detection of DSTs in marine foods.