Fig. 4
Sensitivity analysis of E.coli at different dilution concentrations and count of two real samples by our MNP-based strategy. a 103 dilution of E. coli stock solution (equal to 102 CFU/μL) captured by MNP probe; b 104 dilution of E. coli stock solution (equal to 10 CFU/μL) captured by MNP probe; c 105 dilution of E. coli stock solution (equal to 1 CFU/μL) captured by MNP probe. d PCR analysis of E.coli at different dilution concentrations. M: DNA Marker; Line 1: E. coli stock solution; Line 2–6: 101, 102, 103, 104 and 105 dilution of E. coli stock solution, respectively; Red box in the upper right corner of a, b and c is the enlargement of the selected area, respectively. e A representative dark-field image of E. coli in ten-fold concentration dilute soup sample captured by MNP probes; f A representative dark-field image of E. coli in ten-fold concentration rice sample captured by MNP probes