title: Streptococcus mutans biofilm transient viscoelastic fluid behaviour during high-velocity microsprays.
abstract: Using high-speed imaging we assessed Streptococcus mutans biofilm-fluid interactions during exposure to a 60-ms microspray burst with a maximum exit velocity of 51m/s. S. mutans UA159 biofilms were grown for 72h on 10mm-length glass slides pre-conditioned with porcine gastric mucin. Biofilm stiffness was measured by performing uniaxial-compression tests. We developed an in-vitro interproximal model which allowed the parallel insertion of two biofilm-colonized slides separated by a distance of 1mm and enabled high-speed imaging of the removal process at the surface. S. mutans biofilms were exposed to either a water microspray or an air-only microburst. High-speed videos provided further insight into the mechanical behaviour of biofilms as complex liquids and into high-shear fluid-biofilm interaction. We documented biofilms extremely transient fluid behaviour when exposed to the high-velocity microsprays. The presence of time-dependent recoil and residual deformation confirmed the pivotal role of viscoelasticity in biofilm removal. The air-only microburst was effective enough to remove some of the biofilm but created a smaller clearance zone underlying the importance of water and the air-water interface of drops moving over the solid surface in the removal process. Confocal and COMSTAT analysis showed the high-velocity water microspray caused up to a 99.9% reduction in biofilm thickness, biomass and area coverage, within the impact area.
authors.affiliation: National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, Southampton SO17 1BJ, UK. Electronic address: stefaniafabbri1987@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Fabbri
authors.affiliation: Biomedical Imaging Unit, School of Medicine, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: D A
authors.initials: DA
authors.lastname: Johnston
authors.affiliation: Philips Research, High Tech Campus, Eindhoven 5656 AE, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Rmaile
authors.affiliation: Philips Research, High Tech Campus, Eindhoven 5656 AE, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Gottenbos
authors.affiliation: Philips Research, High Tech Campus, Eindhoven 5656 AE, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: De Jager
authors.affiliation: Wrigley, Chicago, IL 60613, USA.
authors.forename: M
authors.initials: M
authors.lastname: Aspiras
authors.affiliation: Philips Oral Healthcare, Bothell, WA 98021, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Starke
authors.affiliation: Philips Oral Healthcare, Bothell, WA 98021, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Ward
authors.affiliation: National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, Southampton SO17 1BJ, UK; Department of Microbial Infection and Immunity and the Department of Orthopaedics, Centre for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: P
authors.initials: P
authors.lastname: Stoodley
mesh_terms: D000818:Animals; D018441:Biofilms; D013295:Streptococcus mutans / Q000502:physiology*; D013552:Swine; D014783:Viscosity; D014867:Water
chemical_list: D014867:Water
keywords: Biofilm; Fluid dynamics; High-speed camera; Mechanical properties; Oral hygiene; Viscoelasticity