A historical overview of analysis systems for Bacillus thuringiensis (Bt) Cry proteins

[Display omitted] •Qualitative/semi-quantitative and quantitative detection systems for Bt Cry proteins are summarized.•The mechanisms, advantages, limitations and applications of different methods are discussed.•The current challenges and future prospects for determination of Bt proteins are highlighted. Bacillus thuringiensis (Bt) proteins are a series of crystal biotoxins against crop pests and can be directly expressed by transgenic plants with implanted Bt genes. Although genetically modified organisms gain growing acceptance, their biological safety and environmental fate have been a concomitantly controversial issue of public concern. In general, the determination of Bt protein level in plants, water, soil and agricultural commodities is considered as the first step to evaluate the impact of these toxicant proteins on the ecological environment. To date, various platforms have been developed to monitor the content of Bt proteins that are mainly belong to Cry type, yet there still lacks a specific overview to summarize these developments, especially in the case of emerging strategies in the last few years. This paper outlines the progress of detection methods for Bt Cry proteins from the past to recent advances, including not only relatively mature sensing systems such as enzyme-linked immunoabsorbent assay (ELISA) and immunochromatographic strip, but also some novel analysis approaches, for example, electrochemistry and fluorescence. Their mechanisms, advantages, limitations and applications are also presented and discussed in this review. Then, the current challenges and future prospects of this field are also highlighted in the final part.