3.6. In vitro dispersion of established K.pneumoniaebiofilms
Over 60% of all patients’ infections treated by physicians are caused
by biofilms which are of great significance for bacterial attachment and
proliferation, and extremely recalcitrant to antimicrobials44-45. Thus, we further studied the potential
influence for formed K.pneumoniae biofilms mediated by OHH NPs
+NIR. As seen in Fig. 6A, comparing with the control group, separate
HMPB NPs treatment hardly showed dispersion effect on the biofilms. In
comparison, ofloxacin and OHH NPs were able to only remove about 35%
and 26% of the biofilm, respectively, indicating that ofloxacin showed
certain effectiveness in anti-biofilm (Fig. 6B). However, OHH NPs with
laser assistance effectively eliminated the biofilm quantity of ∼90%,
which was likely due to the excellent synergistic effect of ofloxacin
and photothermal ablation. We next performed a fluorescence staining
assay using PI to obtain 3D CLSM images of K.pneumoniae biofilms.
It could be concluded that OHH NPs with NIR irradiation exhibited most
powerful anti-biofilms activity from the strongest red fluorescence in
Fig. 6C and Fig. 6D, which was well consistent with the crystal violet
staining assay.