The anti-biofilm activity of Ca2+- or Mg2+-based complexes. (A) Fluorescent images of E. coli, S. aureus, and A. baumannii without any treatment, treated with fresh MH, or MH released from the complexes. The cells were stained with “ live” SYTO 9 stain (green fluorescence). Scale bar = 20 µm. (B) XTT assay for quantification of surviving bacteria demonstrates significant anti-biofilm activity of fresh MH as well as MH released from the complexes. *, P < 0.05 compared with untreated control. Data shown are average ± STD (n=4).