Figure 5.

MNPs with click-immobilized NRGp17 are a specific, sensitive detection tool. (a) Small-scale E. coli (ECOR#13) detection with no preenrichment. 100 μL samples were treated with 5 log mL⁻¹ unconjugated azide-coated MNPs, 5 log pfu/mL free NRGp17, NRGp17 conjugated to MNPs via WT SOC, or click NRGp17 conjugated to MNPs. Only the latter gives a signal significantly higher than the baseline luminescence. (b) Small-scale detection of 4.01 ± 0.15 log cfu/mL E. coli with no pre-enrichment in pure and mixed culture. Non-coliform bacteria included 3.27 ± 0.33 log cfu/mL P. aeruginosa, 3.82 ± 0.22 log cfu/mL L. monocytogenes, and 3.23 ± 0.07 log cfu/mL S. alaskensis. Error bars indicate the standard deviation of four technical replicates. Bacterial concentration reported as mean ± standard deviation of 12 plate counts. Letters and stars indicate significance (p < 0.05; n.s. = p > 0.05; *** = p < 0.001) by one-way ANOVA and Tukey’s multiple comparison test. Raw data used to construct this figure are reported in Tables S5 and S6.