Ratiometric Detection of Ochratoxin A Using a Regenerable COF-Au-MB-Apt Signal Probe on a Thermal-Regulated Sensor Module

Abstract

Ochratoxin A (OTA) frequently contaminates grains and consequently threatens human health. Herein, we develop a regenerable signal probe and apply it to a Au-based screen-printed electrode module (SPE) for OTA determination. The signal probe, containing a structural covalent organic framework, gold nanoparticles (AuNPs), indicative methylene blue (MB), and a highly selective aptamer, is synthesized with hydrothermal and self-assembly methods. The SPE is permanently functionalized with Prussian blue (PB), AuNPs, and semicomplementary ssDNA. The signal probe, absorbed onto this SPE via hybridization, is competitively expelled by OTA, providing a ratiometric readout of ΔI MB/I PB. Probe regeneration, to erase expired COF-Au-MB-Apt after each analysis, is established with the synergy of OTA-conducted Apt-ssDNA dissociation and on-chip thermal regulation. This advantage powerfully guarantees reduplicative analyses by avoiding irreversible Apt-OTA combination and accumulation on the sensing interface. Regenerations are performed in repetitive cycles (N = 7) with 98.5% reproduction efficiency, and I MB and I PB fluctuations are calculated as 1.45 and 1.12%. This method shows log-linear OTA response in a wide range from 0.2 pg/mL to 0.6 μg/mL, and the limit of detection is 0.12 pg/mL. During natural OTA determinations, recommended readouts match well with HPLC with less than 4.82% relative error.

Host–Guest Interaction Mediated Perovskite@Metal–Organic Framework Z-Scheme Heterojunction Enabled Paper-Based Photoelectrochemical Sensing

“…Therefore, a much enhanced photocurrent was obtained. Due to the high affinity between aptamer DNA and OTA, 37 the aptamer-assistant DNA duplex was disassembled to export assistant DNA, transmitting the OTA into assistant DNA-Ag NPs (Figure 4f). Under irradiation, the Ag NP-mediated EPI effect deeply quenched the photocurrent by promoting the rD rate, achieving the ultrasensitive detection of OTA.…”

Poly-adenine-based DNA Probes and Their Applications in Biosensors★

“…多枝状金纳米颗粒(AuNSs) 拥有尖端和多枝状结构, 比表面积大, 其表面附近可以 产生增强的 SERS 效应 [62] . Guo 等 [63] [64][65][66] . 基于 polyA 与金之间的 相互作用, Koo 等 [67] [67] 相比, 该传感器具有更好的特异性、重复性和稳定性, 对于广 泛用于现场分析具有重要意义.…”

Ratiometric fluorescent aptasensor for convenient detection of ochratoxin A in beer and orange juice

“…To improve detection stability, accuracy and sensitivity of these fluorescent aptasensors, ratiometric fluorescent aptasensors that concurrently have two different signal probes are prepared. [35][36][37] The final signals of ratiometric fluorescent aptasensors are determined by the fluorescence signal ratio of two fluorescent probes.…”