title: Salivary pellicles equalise surfaces' charges and modulate the virulence of Candida albicans biofilm.
abstract: BACKGROUND
  Numerous environmental factors influence the pathogenesis of Candida biofilms and an understanding of these is necessary for appropriate clinical management.
  
  
  OBJECTIVE
  To investigate the role of material type, pellicle and stage of biofilm development on the viability, bioactivity, virulence and structure of C. albicans biofilms.
  
  
  METHODS
  The surface roughness (SR) and surface free energy (SFE) of acrylic and titanium discs was measured. Pellicles of saliva, or saliva supplemented with plasma, were formed on acrylic and titanium discs. Candida albicans biofilms were then generated for 1.5 h, 24h, 48 h and 72 h. The cell viability in biofilms was analysed by culture, whilst DNA concentration and the expression of Candida virulence genes (ALS1, ALS3 and HWP1) were evaluated using qPCR. Biofilm metabolic activity was determined using XTT reduction assay, and biofilm structure analysed by Scanning Electron Microscopy (SEM).
  
  
  RESULTS
  Whilst the SR of acrylic and titanium did not significantly differ, the saliva with plasma pellicle increased significantly the total SFE of both surface. The number of viable microorganisms and DNA concentration increased with biofilm development, not differing within materials and pellicles. Biofilms developed on saliva with plasma pellicle surfaces had significantly higher activity after 24h and this was accompanied with higher expression of virulence genes at all periods.
  
  
  CONCLUSIONS
  Induction of C. albicans virulence occurs with the presence of plasma proteins in pellicles, throughout biofilm growth. To mitigate such effects, reduction of increased plasmatic exudate, related to chronic inflammatory response, could aid the management of candidal biofilm-related infections.
authors.affiliation: Periodontology and Prosthodontics Department, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil; Department of Dentistry, School of Dentistry, State University of Paraíba (UEPB), Campina Grande, PB, Brazil. Electronic address: yuri.wanderley@yahoo.com.br.
authors.forename: Yuri Wanderley
authors.initials: YW
authors.lastname: Cavalcanti
authors.affiliation: Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff, Wales, UK.
authors.forename: Melanie
authors.initials: M
authors.lastname: Wilson
authors.affiliation: Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff, Wales, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Lewis
authors.affiliation: Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff, Wales, UK.
authors.forename: David
authors.initials: D
authors.lastname: Williams
authors.affiliation: Periodontology and Prosthodontics Department, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Plínio Mendes
authors.initials: PM
authors.lastname: Senna
authors.affiliation: Periodontology and Prosthodontics Department, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Altair Antoninha
authors.initials: AA
authors.lastname: Del-Bel-Cury
authors.affiliation: Periodontology and Prosthodontics Department, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil. Electronic address: wanderjose@fop.unicamp.br.
authors.forename: Wander José
authors.initials: WJ
authors.lastname: da Silva
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002176:Candida albicans / Q000166:cytology / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D044622:Dental Pellicle / Q000382:microbiology* / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics; D006801:Humans; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D050296:Microbial Viability; D008855:Microscopy, Electron, Scanning; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011897:Random Allocation; D012471:Salivary Proteins and Peptides / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014774:Virulence
chemical_list: C093538:ALS1 protein, Candida albicans; C113620:ALS3 protein, Candida albicans; D000180:Acrylic Resins; D005656:Fungal Proteins; D012471:Salivary Proteins and Peptides; D019904:Polymethyl Methacrylate; D014025:Titanium
keywords: Biofilms; Candida; Gene expression; Salivary pellicle; Virulence