A turn-on-type fluorescence resonance energy transfer aptasensor for vibrio detection using aptamer-modified polyhedral oligomeric silsesquioxane-perovskite quantum dots/Ti3C2 MXenes composite probes.

Abstract

A pair of composite probes based on aptamer modified polyhedral oligomeric silsesquioxane-perovskite quantum dots (POSS-PQDs-Apt) as signal probe and titanium carbide (Ti3C2) MXenes as quencher were prepared for the first time. They were employed to fabricate one turn-on-type aptasensor relying on fluorescence resonance energy transfer (FRET) for Vibrio parahaemolyticus (VP) determination. The POSS-PQDs-Apt can be adsorbed on the MXenes nanosheets, and its fluorescence was quenched due to the FRET. After the composite probes were incubated with VP for 50min, the POSS-PQDs-Apt binding with VP can be released from the surface of MXenes, and the signal recovered due to its higher affinity to the VP than MXenes. The fluorescence intensity from 519nm emission of the system was measured at 480nm excitation. UnderIn optimized conditions, the assay can determine VP inthe concentration range102 - 106cfu/mL, and the detection limit (LOD) was 30cfu/mL using fluorescence detection. TheLOD is still100cfu/mL by naked eye detection which is proper for on-line monitoring VP in aquaculture water. This method was also used to detect VP in actual samples of seawater, the recovery of spiked samples was between 93% and 106%, and relative standard deviation (RSD) was between 2.7% and 6.7%. The result is consistent with the plate count. Therefore, this assay could provide a candidate platform for screening VP in aquaculture industry.