title: Effects of photodynamic laser and violet-blue led irradiation on Staphylococcus aureus biofilm and Escherichia coli lipopolysaccharide attached to moderately rough titanium surface: in vitro study.
abstract: Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This study investigates the in vitro efficacy of photodynamic treatment (PDT) with methylene blue (MB) photoactivated with λ 635 nm diode laser and of λ 405 nm violet-blue LED phototreatment for the reduction of bacterial biofilm and lipopolysaccharide (LPS) adherent to titanium surface mimicking the bone-implant interface. Staphylococcus aureus biofilm grown on titanium discs with a moderately rough surface was subjected to either PDT (0.1% MB and λ 635 nm diode laser) or λ 405 nm LED phototreatment for 1 and 5 min. Bactericidal effect was evaluated by vital staining and residual colony-forming unit count. Biofilm and titanium surface morphology were analyzed by scanning electron microscopy (SEM). In parallel experiments, discs coated with Escherichia coli LPS were treated as above before seeding with RAW 264.7 macrophages to quantify LPS-driven inflammatory cell activation by measuring the enhanced generation of nitric oxide (NO). Both PDT and LED phototreatment induced a statistically significant (p < 0.05 or higher) reduction of viable bacteria, up to -99 and -98% (5 min), respectively. Moreover, besides bactericidal effect, PDT and LED phototreatment also inhibited LPS bioactivity, assayed as nitrite formation, up to -42%, thereby blunting host inflammatory response. Non-invasive phototherapy emerges as an attractive alternative in the treatment of peri-implantitis to reduce bacteria and LPS adherent to titanium implant surface without causing damage of surface microstructure. Its efficacy in the clinical setting remains to be investigated.
authors.affiliation: Odontostomatologic Laser Therapy Center, Via dell' Olivuzzo 162, 50143, Florence, Italy. dott.giannellimarco@gmail.com.
authors.forename: Marco
authors.initials: M
authors.lastname: Giannelli
authors.affiliation: Department of Medical Biotechnologies, Santa Maria alle Scotte University Hospital, University of Siena, Viale Bracci, Siena, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Landini
authors.affiliation: Odontostomatologic Laser Therapy Center, Via dell' Olivuzzo 162, 50143, Florence, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Materassi
authors.affiliation: Department of Experimental and Clinical Medicine-Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Flaminia
authors.initials: F
authors.lastname: Chellini
authors.affiliation: Department of Medical Biotechnologies, Santa Maria alle Scotte University Hospital, University of Siena, Viale Bracci, Siena, Italy.|Department of Experimental and Clinical Medicine, Section of Critical Care and Specialistic Medicine, University of Florence, Florence, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Antonelli
authors.affiliation: Department of Experimental and Clinical Medicine-Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Tani
authors.affiliation: Department of Experimental and Clinical Medicine-Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Nosi
authors.affiliation: Department of Experimental and Clinical Medicine-Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Zecchi-Orlandini
authors.affiliation: Department of Medical Biotechnologies, Santa Maria alle Scotte University Hospital, University of Siena, Viale Bracci, Siena, Italy.|Department of Experimental and Clinical Medicine, Section of Critical Care and Specialistic Medicine, University of Florence, Florence, Italy.|Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Via San Damiano, 50134, Florence, Italy.
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
authors.affiliation: Department of Experimental and Clinical Medicine-Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Bani
mesh_terms: D000818:Animals; D018441:Biofilms / Q000528:radiation effects*; D004926:Escherichia coli / Q000187:drug effects / Q000528:radiation effects* / Q000648:ultrastructure; D005453:Fluorescence; D054023:Lasers, Semiconductor; D008027:Light; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D050296:Microbial Viability / Q000528:radiation effects; D010778:Photochemotherapy; D000067996:RAW 264.7 Cells; D013211:Staphylococcus aureus / Q000187:drug effects / Q000528:radiation effects* / Q000648:ultrastructure; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D008070:Lipopolysaccharides; D014025:Titanium
keywords: Dental implants; Diode laser; LED; Lipopolysaccharide; Methylene blue; Staphylococcus aureus