Fig. 8: Colonization of pro- (697) and anti- (881) attachment PU TopoUnits compared with flat PU implanted subcutaneously in mice.

After implantation, mice were allowed to recover for 4 days prior to infection with P. aeruginosa for a further 4 days. The implants were recovered and imaged via confocal fluorescence microscopy. a Representative images of P. aeruginosa PAO1 pcE2C (red) constitutively expressing the fluorescent protein E2Crimson. Upper panels, scale bar 50 µm; Lower panels, fluorescent images overlaid on brightfield images; scale bar, 20 µm. b Quantification of P. aeruginosa pcE2C surface coverage from individual explants (one per mouse) using constitutive E2C fluorescence. TopoUnits 881 (n = 8 mice) and 697 (n = 7 mice; one implant was unrecoverable) were compared with Flat PU (n = 8 mice). Statistical analysis was done using one way ANOVA with Tukey’s multiple comparison test. 697 vs 881, p = <0.0001 ****; flat vs 881, p = <0.0001 ****; flat vs 697 p = 0.9328, NS, not significant. The source data are provided as a Source Data file. c Representative images of explanted TopoUnits 881 and 697 stained for bacteria and host cells. Lefthand panels: orange, PAO1 bacteria detected using IHC antibody PA1-73116 and secondary anti-rabbit Alexa 555. Righthand panels: brightfield images of the lefthand panels stained in addition with DAPI (for DNA nuclei, blue) and FM1-43 (for cell membranes, green). Scale bars, 10 μm. d Sterile explant recovered after 4 days showing increased host cell migration on the upper side of TopoUnit 881 compared with the flat side indicative of an asymmetrical host response. Blue, DAPI, DNA stained nuclei (blue), FM1-43 stained membranes, green. Scale bar, 100 μm.