Extended Data Fig. 3: Surface cell concentration limit-of-detection of HSRs.
Note that the limit-of-detection will be dependent on the specific camera and distance from the bacteria. Known concentrations of bacteria added to filter surfaces and imaged by a VNIR hyperspectral camera (Headwall E-Series) from 0.5 m (Methods). a. RGB and classified images extracted from the HSI data for constitutively-produced SmURFP(biliverdin IXα) (E. coli pYC301). b. Dependence of signal on the cell density. The limit-of-detection is marked with the vertical dashed line. The data points represent three replicates. The mean classification score indicates that it was averaged over the area of each well. c. Statistical significance of the signal in the presence compared to the absence of cells. p-values were calculated for the mean classification scores of 0.0 CFU/mm2 and each cell density, using one-sided Student t-test with equal variance. The horizontal line is the threshold used to define significant (p-value = 0.05). d. Mean reflectance spectra as a function of cell density. The absorption peak at 925 nm is due to the filter material. e. RGB and classified images extracted from the HSI data for cells constitutively producing bacteriochlorophyll a (R. gelatinosus YF6). f. Dependence of signal on the cell density. The limit-of-detection is marked with the vertical dashed line. The data points represent three replicates. g. Statistical significance of the signal in the presence compared to the absence of cells. p-values were calculated for the mean classification scores of 0.0 CFU/mm2 and each cell density, using one-sided Student t-test with equal variance. h. Reflectance spectra as a function of cell density. The data points are three replicates.
