2D Carbon Nitride-Based Electrochemical Aptasensor for Label-Free and Highly-Sensitive Detection of Okadaic Acid in Shellfish

Abstract

Okadaic acid (OA) is a marine toxin accumulated in bivalves causing severe diarrhetic shellfish poisoning, which has become a threat to human health, food safety, and environmental protection. Therefore, it is essential to develop cost-effective and convenient approaches for OA detection. Recent advances in the electrochemical and nanotechniques may provide novel approaches to address this issue. Herein, we developed a label-free electrochemical impedance aptasensor for sensitive detection of OA in shellfish. Two-dimensional carbon nitride conjugated aptamers were employed as the sensitive element for OA detection, which was prepared and characterized by scanning electron microscope and transmission electron microscope. The obtained results indicate this aptasensor exhibited a good performance for the OA detection with a wide linearity ranging from 1×10-14 mol L-1 to 1×10-7 mol L-1. The limit of detection was 1×10-14 mol L-1. In addition, this aptasensor had a good selectivity toward dinophysistoxins, pectenotoxins, and yessotoxin. This aptasensor also showed good reproducibility and stability. Most importantly, the detection with real mussel samples showed good recovery rate. The simple and cost-effective sensing strategy to marine toxins could be applied in the fields of seafood safety and water quality control.

A 2D carbon nitride-based electrochemical aptasensor with reverse amplification for highly sensitive detection of okadaic acid in shellfish

“…The structural and functional properties of these nanosheets have already been previously analysed using XRD pattern analysis and FTIR spectra technology. 24 In this work, the morphology of these prepared nanosheets and functional nanosheets was further explored using SEM where a dispersion of nanosheets was briefly ultrasound-treated in alcohol and dried naturally on silicon chips at room temperature, respectively (Fig. 1(a)).…”

“…23 As a result, it has been widely used as a carrier of sensitive materials in biosensor construction, which greatly eliminates the limitations of a narrow working area on the transducer surface to effectively broaden the quantication range, and simultaneously improve the detection performance of electrochemical biosensors. [24][25][26] Currently, based on nanomaterials, aptamers, single-stranded DNA and even antibodies, a novel three-layer structure detection mode has attracted more attention due to its high sensitivity, good selectivity and wider quantication range, offering an effective detection direction for small molecule detection. [27][28][29] Furthermore, the electrochemical analysis method has great preponderance in inexpensive and highly sensitive detection of small molecules.…”

DNA walker coupled with nicking endonuclease for sensitive electrochemical detection of saxitoxin

“…Fresh mussels were bought from the local market and treated following the previous method. 26 Briefly, the tissues were extruded and broken using a home grinder. Then, 250 mg tissues were mixed with 1 ml of 50% methanol for 5 min.…”