Photodynamic inactivation mediated by methylene blue or chlorin e6 against Streptococcus mutans biofilm

dc.contributor.authorNie, Min
dc.contributor.authorDeng, Dong Mei
dc.contributor.authorWu, Yafei
dc.contributor.authorde Oliveira, Kleber Thiago
dc.contributor.authorBagnato, Vanderlei Salvador
dc.contributor.authorCrielaard, Wim
dc.contributor.authorRastelli, Alessandra Nara de Souza [UNESP]
dc.contributor.institutionSichuan University
dc.contributor.institutionUniversity of Amsterdam and Vrije Universiteit Amsterdam
dc.contributor.institutionNorthwest Minzu University
dc.contributor.institutionUniversidade Federal de São Carlos (UFSCar)
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.description.abstractBackground: An appropriate photosensitizer (PS) for photodynamic inactivation should have a pronounced antimicrobial efficacy but low dark toxicity. The aim of this study is to investigate the concentration-dependent antimicrobial efficacies of methylene blue (MB) and chlorin e6 (Ce6), against Streptococcus mutans biofilms and to compare the efficacies of these two PSs. Methods: The 48-h S. mutans UA159 biofilms, grown on glass coverslips, were subjected to MB or Ce6 at 25, 50, 100 and 200 μM with or without irradiation by 660 nM LED light (L). Control groups (-PS-L and -PS + L) were also included. Viability of the biofilm was analyzed by CFU/biofilm and biofilm lactic acid production was quantified by an enzymatic assay. Results: With irradiation, MB under 25 μM resulted in 2-log reduction in biofilm viability and 30-fold reduction in biofilm lactic acid production. However, this biofilm killing efficacy did not change with increasing MB concentration. The biofilm killing efficacy of Ce6 increased with increasing Ce6 concentrations and resulted in 5-log reduction in biofilm viability. The lactic acid inhibitory effect of Ce6 was significantly lower than MB at 25 μM (p<0.01) but higher than MB at 200 μM (p=0.05), although the difference at 200 μM did not reach statistical significance. No dark toxicity could be observed for MB whereas low dark toxicity could be seen for Ce6 when the concentration is above 50 μM. Conclusion: Ce6 under 200 μM showed to be a more powerful PS for photodynamic inactivation than MB. Both Ce6- and MB-based photodynamic inactivation are useful methods for biofilm control in caries prevention.en
dc.description.affiliationState Key Laboratory of Oral Diseases West China Hospital of Stomatology Sichuan University
dc.description.affiliationDepartment of Preventive Dentistry Academic Centre for Dentistry Amsterdam University of Amsterdam and Vrije Universiteit Amsterdam
dc.description.affiliationKey Lab of Oral Diseases of Gansu Province Northwest Minzu University
dc.description.affiliationFederal University of São Carlos – UFSCar Department of Chemistry
dc.description.affiliationUniversity of São Paulo - USP Physics Institute of São Carlos - IFSC Optical Group Campus São Carlos
dc.description.affiliationUniversity of São Paulo State – UNESP Araraquara School of Dentistry Department of Restorative Dentistry, Campus Araraquara
dc.description.affiliationUnespUniversity of São Paulo State – UNESP Araraquara School of Dentistry Department of Restorative Dentistry, Campus Araraquara
dc.identifier.citationPhotodiagnosis and Photodynamic Therapy, v. 31.
dc.relation.ispartofPhotodiagnosis and Photodynamic Therapy
dc.subjectChlorin e6
dc.subjectLactic acid production
dc.subjectMethylene blue
dc.subjectPhotodynamic inactivation
dc.subjectStreptococcus mutans
dc.titlePhotodynamic inactivation mediated by methylene blue or chlorin e6 against Streptococcus mutans biofilmen