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. 2022 Jun 14;13:3432. doi: 10.1038/s41467-022-31171-0

Fig. 2. Characterization of ECN-pE(C/A)2.

Fig. 2

a Zeta potential of ECN-pE with different chitosan/sodium alginate layer coatings during the preparation of ECN-pE(C/A)2. b Fluorescence intensity of ECN-pE with different fluorescence-labeled chitosan or sodium alginate layers. Chitosan was labeled with Cy5.5, and sodium alginate was labeled with FITC. a.u. arbitrary unit. c The relative viabilities of ECN-pE before and after different coatings as indicated. d Western blot analysis of the expression of CAT and SOD. CAT catalase, SOD superoxide dismutase. A representative western blot image from two independent experiments. e The ·O2− inhibition rate of ECN(C/A)2(−), ECN(C/A)2(+), ECN-pE(C/A)2(-) and ECN-pE(C/A)2(+) at the same concentration of 107 CFU/mL. ECN(C/A)2(−): ECN(C/A)2 without 1 mM IPTG induction, ECN(C/A)2(+): ECN(C/A)2 with 1 mM IPTG induction, ECN-pE(C/A)2(−): ECN-pE(C/A)2 without 1 mM IPTG induction, ECN-pE(C/A)2(+): ECN-pE(C/A)2 with 1 mM IPTG induction. f The ·O2− inhibition rate of ECN-pE(C/A)2(+) at different concentrations (105–107 CFU/mL). g The oxygen generation capacity of ECN(C/A)2(−), ECN(C/A)2(+), ECN-pE(C/A)2(−), and ECN-pE(C/A)2(+) in H2O2 solutions with the same concentration of 5 × 108 CFU/mL. h The oxygen generation capacity of ECN-pE(C/A)2(+) with different concentrations of ECN-pE(C/A)2 (107–5 × 108 CFU/mL). i, j Representative TEM images of ECN-pE and ECN-pE(C/A)2 after exposure to SGF or 4% bile salt at 37 °C for 2 h from two independent samples. Scale bar: 1 μm. k Survival quantification of ECN-pE and ECN-pE(C/A)2 exposed to 4% bile salt solution or simulated gastric fluid (SGF) for different times. l, m IVIS bioluminescence images of mice and their GI tract 3 h post-oral gavage by ECN-lux or ECN-lux(C/A)2. ECN-lux ECN(pET28a-T5-luxCDABE). n Quantification evaluation of bioluminescence signals of ECN-lux and ECN-lux(C/A)2 in mice. o–r Quantification analysis of living ECN-pE in the stomach, intestine, colon, and cecum 1, 3, 48, and 72 h post-oral gavage by ECN and ECN(C/A)2. Data are presented as mean values ± SEM (n = 3 biologically independent samples for (a, b, e, f, k, and n), n = 6 biologically independent samples for (c and o–r)). Statistical analysis was evaluated with two-tailed Student’s t tests (*P  < 0.05, **P  < 0.01, ***P  <  0.001, ****P  < 0.0001). CFU colony-forming units, SGF simulated gastric fluid. Source data are provided as a Source Data file.