title: The significance of calcium ions on Pseudomonas fluorescens biofilms - a structural and mechanical study.
abstract: The purpose of this study was to investigate the effects of calcium ions on the structural and mechanical properties of Pseudomonas fluorescens biofilms grown for 48 h. Advanced investigative techniques such as confocal laser scanning microscopy and atomic force spectroscopy were employed to characterize biofilm structure as well as biofilm mechanical properties following growth at different calcium concentrations. The presence of calcium during biofilm development led to higher surface coverage with distinct structural phenotypes in the form of a granular and heterogeneous surface, compared with the smoother and homogeneous biofilm surface in the absence of calcium. The presence of calcium also increased the adhesive nature of the biofilm, while reducing its elastic properties. These results suggest that calcium ions could have a functional role in biofilm development and have practical implications, for example, in analysis of biofouling in membrane-based water-treatment processes such as nanofiltration or reverse osmosis where elevated calcium concentrations may occur at the solid-liquid interface.
authors.affiliation: a School of Chemical and Bioprocess Engineering , University College Dublin (UCD) , Belfield , Dublin , Ireland.
authors.forename: Ashkan
authors.initials: A
authors.lastname: Safari
authors.forename: Olivier
authors.initials: O
authors.lastname: Habimana
authors.forename: Ashley
authors.initials: A
authors.lastname: Allen
authors.forename: Eoin
authors.initials: E
authors.lastname: Casey
mesh_terms: D018441:Biofilms / Q000187:drug effects*; D002118:Calcium / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D007477:Ions / Q000494:pharmacology*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D011551:Pseudomonas fluorescens / Q000187:drug effects* / Q000502:physiology; D013499:Surface Properties
chemical_list: D007477:Ions; D002122:Calcium Chloride; D002118:Calcium
keywords: CaCl2; Pseudomonas fluorescens; Young’s modulus; biofilm; force spectroscopy