Song Wang,Lantian Su,Lumei Wang,Dongwei Zhang,Guoqing Shen,Yun Ma
This paper proposes the idea of establishing carbendazim (CBZ) colorimetric determination in spiked water samples by specific aptamers of unlabeled carbendazim (CBZ), gold nanoparticles (AuNPs) and cationic polymer poly-diallyldimethylammonium chloride (PDDA). In the absence of CBZ, the CBZ aptamer will react with the cationic polymer PDDA by electrostatic interaction to form a complex structure. Therefore, the gold nanoparticles will remain dispersed due to the lack of PDDA. However, when CBZ is added into the sensory system, the CBZ-specific aptamer can selectively capture CBZ to form a stable complex structure. Due to the consumption of the aptamer, PDDA is unable to interact with the aptamer and begins to induce aggregation of AuNPs, thereby causing the color of the solution to change from red to blue. Colorimetric determination of CBZ based on the specific recognition of aptamer and the PDDA-induced aggregation of AuNPs has a detection limit of 2.2 nM, a linear range (R = 0.9960) from 2.2 to 500 nM. The method has good sensitivity and specificity, and the average recovery of CBZ is 94.9–104.8% in the application of actual water samples. This colorimetric method is simple, time-saving and low requirements for equipment, therefore, it holds great potential for CBZ detection in the environmental water samples.
A novel electrochemical sensor for highly sensitive and selective detection of carbendazim (CBD) in food was proposed in this study. Initially, a three-dimensional carbon composite material (CCM) was formed by simultaneously modifying reduced graphene oxide and reduced graphene nanoribbons on the glassy carbon electrode (GCE) to enhance sensitivity and serve as a stable sensing platform. Then copper nanoparticles were electrodeposited on CCM/GCE, and cyclic voltammetry scanning was performed in potassium ferrocyanide solution to deposit copper-based Prussian blue analogue on CCM/GCE, further improving the sensitivity of the sensor while giving the ability to self-report. Magnetic molecularly imprinted metal-organic framework materials were then dropped onto the electrode to enhance its detection specificity and adsorption capacity for CBD. The sensor has a wide linear range (0.25 nmol/L ∼ 1000 nmol/L) and a low detection limit (0.08 nmol/L), and the recovery rate of CBD in actual corn flour samples is 99.74 % ∼ 102.58 %.
Zongyou Chen,Yanyan Tang,Ping Guo,Wei Zhang,Juan Peng,Yonghua Xiong,Bingfeng Ma,Weihua Lai
High fluorescence intensity microspheres such as aggregation-induced emission fluorescence microspheres (AIEFM) have improved the sensitivity of lateral flow immunoassay (LFIA). The preparation of immune probes in LFIA usually adopts the chemical coupling strategy with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide for antibody coupling, which has the problems of low coupling efficiency, tedious coupling process, and poor repeatability. A biocompatible metal-phenolic network (MPN), which contains large amounts of phenols and galloyl groups, could easily, quickly, and stably couple with antibodies. Herein, we proposed a strategy based on MPN modification on ultrabright AIEFM surface as a novel label for the rapid detection of carbendazim. The limit of detection of AIEFM@MPN-LFIA was 0.019 ng/mL, which was 4.9 times lower than that of AIEFM-LFIA. In spiked samples, the average recoveries of AIEFM@MPN-LFIA ranged from 80% to 118% (coefficient of variation <13.45%). Therefore, AIEFM@MPN was a promising signal label that could improve the detection performance of LFIA.