title: Dynamics of Pseudomonas aeruginosa association with anionic hydrogel surfaces in the presence of aqueous divalent-cation salts.
abstract: Binding of bacteria to solid surfaces is complex with many aspects incompletely understood. We investigate Pseudomonas aeruginosa uptake kinetics onto hydrogel surfaces representative of soft-contact lenses made of nonionic poly(2-hydroxyethylmethacrylate) (p-HEMA), anionic poly(methacrylic acid) (p-MAA), and anionic poly(acrylic acid) (p-AA). Using a parallel-plate flow cell under phase-contrast microscopy, we document a kinetic "burst" at the anionic hydrogel surface: dilute aqueous P. aeruginosa first rapidly accumulates and then rapidly depletes. Upon continuing flow, divalent cations in the suspending solution sorb into the hydrogel network causing the previously surface-accumulated bacteria to desorb. The number of bacteria eventually bound to the surface is low compared to the nonionic p-HEMA hydrogel. We propose that the kinetic burst is due to reversible divalent-cation bridging between the anionic bacteria and the negatively charged hydrogel surface. The number of surface bridging sites diminishes as divalent cations impregnate into and collapse the gel. P. aeruginosa association with the surface then falls. Low eventual binding of P. aeruginosa to the anionic hydrogel is ascribed to increased surface hydrophilicity compared to the counterpart nonionic p-HEMA hydrogel.
authors: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
authors: Victoria B
authors: VB
authors: Tran
authors: Ye Suel
authors: YS
authors: Sung
authors: Suzanne M J
authors: SM
authors: Fleiszig
authors: David J
authors: DJ
authors: Evans
authors: C J
authors: CJ
authors: Radke
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D001665:Binding Sites; D002122:Calcium Chloride / Q000737:chemistry; D002413:Cations, Divalent / Q000737:chemistry; D003261:Contact Lenses / Q000382:microbiology*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008689:Methacrylates / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012965:Sodium Chloride / Q000737:chemistry; D017155:Wettability
chemical_list: D000180:Acrylic Resins; D002413:Cations, Divalent; D008689:Methacrylates; D011109:Polymethacrylic Acids; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D012965:Sodium Chloride; C006903:carbopol 940; C005044:hydroxyethyl methacrylate; D002122:Calcium Chloride