A facile and integrated aptamer-based platform for preliminary and simultaneous screening of group targets

Highly efficient detection of group targets is of great significance. Okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2) are the main diarrhetic shellfish poisons (DSPs) and have similar structures. As essential auxiliary tools, facile methods for simultaneous screening of these three DSPs are urgently needed. In this study, we report an aptamer-based platform which integrates pretreatment and quantitation for preliminary and simultaneous screening of the three DPSs. With computational study-assisted post-selection strategies, a truncated aptamer and a pair of split aptamers were generated with group-specific and high affinity towards the DSPs. The truncated aptamer was adopted to prepare an aptamer affinity column (AAC) for enrichment and purification of DSPs in real samples. The split aptamers were combined with G-quadruplex-hemin nanozyme to fabricate a label-free colorimetric aptasensor for quantitation. The prepared AAC showed good enrichment capacity. The developed colorimetric aptasensor provided high sensitivity, with limit of detection of 0.7011 nM, 14.27 nM, and 5.374 nM towards OA, DTX-1, and DTX-2, respectively, as well as high selectivity and accuracy. UPLC-MS was then only needed to analyze the suspicious positive samples, and highly efficient detection was achieved. This robust platform could be referred for preliminary screening of other group analytes.