Abstract: Quorum sensing (QS) is the unique, diverse group behavior phenomenon occurred when the bacterium grows to a certain density and responses mutually, and it is responsible for the gene expression and the regulation．There are three kinds of QS singanls, including AI-1, AI-2 and AI-3. Among them, AI-1, i.e. N-Acyl-homoserine lactones (AHL), is the most well-known QS signals and regulates the expression of many physiological characteristic in Gram negative bacteria．The traditional dection method main depends on thin-layer chromatography (TCL). However, some shortcomings still exist in this classical methods, including uneven pigment, color-spot disperse, and low resolution. So, it is important to set up an optimizatd method for rapid, simple and effective detection of AHLs. In this study, a modified protocol was developed based on the traditional TLC method, including design a preparating-agar plate, modified the operating procedure to combine the TLC with biosensor, and save the X-gal′ usage. The results showed that the new protocal have higher resolution, stronger pigmentation, and better surface mobility. More interestingly, the modified method can bring convenient for the natural samples or mixed samples．This new method is efficient, sensitive, inexpensive and easy to apply for the detection of AHLs and analogue．

Key words: quorum sensing, N-Acyl-homoserine lactones, thin-layer chromatography, optimized preparing-gel plate, high resolution