Simple Design Concept for Dual-Channel Detection of Ochratoxin A Based on Bifunctional Metal–Organic Framework

Abstract

A simple fluorescence and electrochemical dualchannel biosensor based on bifunctional Zr(IV)-based metal− organic framework (Zr-MOF) was proposed to detect Ochratoxin A (OTA). The bifunctional Zr-MOF, with photoluminescence properties and enormous electroactive ligands, was exploited to load OTA-specific aptamers for designing signal probes, greatly simplifying the probe-fabrication process and improving sensing reliability. Upon specific recognition of aptamer toward OTA, the anchored probe was released from the sensing interface into the reaction solution. In this circumstance, the increased amount of the signal probe in reaction solution led to an enhanced fluorescence response, while the decreased amount of the signal probe on the sensing interface resulted in a diminished electrochemical response. According to the dual-channel signal change with increasing OTA concentration, the visual fluorescence strategy was established for intuitive OTA detection, and meanwhile, sensitive electrochemical assay with a detection limit of 0.024 pg/mL was also achieved with the help of one-step electrodeposition as a sensing platform. Moreover, the proposed dual-channel assay has been successfully applied to determine OTA levels in corn samples with rapid response, superior accuracy, and high antiinterference capability, providing a promising method for food safety monitoring.

An Overview of the Design of Metal-Organic Frameworks-Based Fluorescent Chemosensors and Biosensors

“…Ochratoxin A (OTA) is primarily generated through the consumption of improperly stored food products and uptake of OTA may cause organ damage. Recently, Li et al developed a Zr-MOFs-based fluorescent and electrochemical dual-channel biosensor for OTA detection [ 169 ]. As displayed in Figure 11 B, in the presence of OTA, its aptamer was released from the surface of Zr-MOFs due to the specific interaction between them.…”

“…( B ) Schematic illustration of the dual-channel Zr-MOFs-based detection strategy of OTA. Reproduced with permission [ 169 ]. Copyright 2022, American Chemical Society.…”

MOF-Based Mycotoxin Nanosensors for Food Quality and Safety Assessment through Electrochemical and Optical Methods

“…Additionally, Lin et al (2022) [ 67 ] demonstrated a Zr-MOF highly porous gold electrochemical and fluorescence dual-channel biosensor with a 1.0 × 10 −7 –0.14 × 10 −3 mg/L linear range and 2.4 × 10 −8 mg/L detection limit sensing ochratoxin A (OTA) in corn samples. Additionally, this sensor showed fluorescence intensity positively connected with that of OTA throughout a concentration range of 1.0 × 10 −7 to 0.16 × 10 −3 mg/L, with a detection limit of 5.1 × 10 −8 mg/L.…”

“… Graphical description of the dual-channel detecting of ochratoxin A (OTA). Adapted with permission from the article [ 67 ]. 2022, American Chemical Society.…”

A portable test strip fabricated of luminescent lanthanide-functionalized metal–organic frameworks for rapid and visual detection of tetracycline antibiotics

“…5–7 For instance, continuous intake of animal-derived food products contaminated by TC residues can lead to decreased immunity, liver toxicity, allergic reactions, gastrointestinal disorders, genetic disorders and different types of cancer. 8–11 Many countries have developed relevant regulations on the maximum residue limit (MRL) of TC in foodstuffs, for example, the US Food and Drug Administration and the European Union stipulated that the MRL of TC in milk is 676 nmol L −1 and 225 nmol L −1 , 12 respectively, while China's relevant regulation is 100 g kg −1 (corresponding to 225 nmol L −1 ). Therefore, it is of utmost significance to develop a rapid and low-cost method for on-site monitoring of TCs for the well-being of human and environmental safety.…”