Aflatoxin B1 (AFB1) is a mycotoxin and is the most carcinogenic of all known chemicals. In view of the AFB1 characteristics of widespread distribution, serious pollution, great harm to humans, and animals and difficult to remove, it is urgent to develop a convenient and sensitive detection method. Moreover, chromatographic test strips (CTSs) are a rapid detection technology that combines labeling technology with chromatography technology. CTSs have been widely used in the fields of environmental monitoring, medical diagnosis, and food safety analysis in recent years. Different from other immune assays, they have the advantages of short measuring time, low cost, high efficiency and no need for professionals to operate. In addition, the introduction of nanomaterials has laid a good foundation for the detection of high sensitivity, high specificity and high efficiency via CTSs. Herein, we tend to comprehensively introduce the applications of chromatographic methods in AFB1 detection and pay attention to the signal detection modes based on nanomaterials in antibody-based immunochromatographic strips (ICSs), such as colorimetric, fluorescent, chemiluminescent, and Raman scattering sensing. Some typical examples are also listed in this review. In the end, we make a summary and put forward prospects for the development of CTSs. Graphical Abtsract

A signal-enhanced lateral flow strip biosensor has been constructed for ultrasensitive and on-site visual detection of bisphenol A (BPA). The signal amplification principle is based on the capacity of binding a large number of antibody-assembled gold nanoparticle (AuNP–antibody) conjugates of the poly amidoamine (PAMAM), which bears a multitude of amino groups. This signal-enhanced method could achieve BPA detection at 10 ppb based on naked eye visual observation, which represents an at least 50-fold improvement of the sensitivity of a traditional method without PAMAM. Moreover, good linearity was observed in the range from 2 to 100 ppb after quantitative analysis using the ImageJ software. This signal amplification method could be adopted as a potential generous technique in different fields.

It is still challenging to achieve simultaneous and sensitive detection of multiple organophosphorus pesticides (OPs). Herein, we optimized the ssDNA templates for the synthesis of silver nanoclusters (Ag NCs). For the first time, we found that the fluorescence intensity of T base-extended DNA-templated Ag NCs was over three times higher than the original C-riched DNA-templated Ag NCs. Moreover, a “turn-off” fluorescence sensor based on the brightest DNA-Ag NCs was constructed for the sensitive detection of dimethoate, ethion and phorate. Under strong alkaline conditions, the P-S bonds in three pesticides were broken, and the corresponding hydrolysates were obtained. The sulfhydryl groups in the hydrolyzed products formed Ag-S bonds with the silver atoms on the surface of Ag NCs, which resulted in the aggregation of Ag NCs, following the fluorescence quenching. The fluorescence sensor showed that the linear ranges were 0.1–4 ng/mL for dimethoate with a limit of detection (LOD) of 0.05 ng/mL, 0.3–2 µg/mL for ethion with a LOD of 30 ng/mL, and 0.03–0.25 µg/mL for phorate with a LOD of 3 ng/mL. Moreover, the developed method was successfully applied to the detection of dimethoate, ethion and phorate in lake water samples, indicating a potential application in OP detection.