Electrochemical Biosensor Based on Well-Dispersed Boron Nitride Colloidal Nanoparticles and DNA Aptamers for Ultrasensitive Detection of Carbendazim.

A selective electrochemical biosensor was developed for detecting carbendazim (CBZ) based on well-dispersed colloidal boron nitride (BN) nanocrystals and gold nanoparticles (Au NPs). BN was synthesized by "solvent cutting" to modify a glassy carbon electrode (GCE), and Au NPs were then electrodeposited. A single-stranded oligonucleotide with methylene blue (MB) was modified to the electrode surface through gold-sulfur bonds. A double-stranded DNA was formed in the presence of an aptamer. The aptamer chain can specifically bind to the target CBZ. When the aptamer binds to CBZ, the electroactive substance MB labeled at one end of the complementary chain can effectively contact the electrode surface. Detection of CBZ is realized by simultaneously monitoring the MB signal enhancement. The CBZ concentration was determined in a wide linearity range from 0.1 ng mL to 100 μg mL, with a low detection limit of 0.019 ng mL. This biosensor exhibited excellent selectivity and acceptable repeatability and was applied in cucumber, kiwifruit, and water samples with good recoveries, demonstrating that the strategy has remarkable potential and offers a good platform for CBZ detection.