Fig. 4.

Specificity analysis of BACA method for bacteria detection. Bacteria species-specific target detection by fluorometric (a) and colorimetric (b) biosensor respectively. The BoNT/A substrate SNAPtide (FITC/DABCYL) was then added to the assay with a final concentration of 5 μM. Reactions were incubated in a fluorescence plate reader (BioTek H1 microplate reader) with fluorescence read every 5 min as a fluorometric biosensor. The color changes of supernatant could be observed to the naked eyes or measured by UV–vis spectrophotometer at 520 nm (n = 3 technical replicates, bars represent mean ± s.d.). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)