Assessment of Photodynamic Inactivation against Periodontal Bacteria Mediated by a Chitosan Hydrogel in a 3D Gingival Model.

Po-Chun Peng,Tsuimin Tsai,Chien-Ming Hsieh,Chueh-Pin Chen,Chin-Tin Chen

doi:10.3390/ijms17111821

Po-Chun Peng, Tsuimin Tsai + Show 3 more

Open Access

https://doi.org/10.3390/ijms17111821

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Abstract

Chitosan hydrogels containing hydroxypropyl methylcellulose (HPMC) and toluidine blue O were prepared and assessed for their mucoadhesive property and antimicrobial efficacy of photodynamic inactivation (PDI). Increased HPMC content in the hydrogels resulted in increased mucoadhesiveness. Furthermore, we developed a simple In Vitro 3D gingival model resembling the oral periodontal pocket to culture the biofilms of Staphylococcus aureus (S. aureus), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), and Porphyromonas gingivalis (P. gingivalis). The PDI efficacy of chitosan hydrogel was examined against periodontal biofilms cultured in this 3D gingival model. We found that the PDI effectiveness was limited due to leaving some of the innermost bacteria alive at the non-illuminated site. Using this 3D gingival model, we further optimized PDI procedures with various adjustments of light energy and irradiation sites. The PDI efficacy of the chitosan hydrogel against periodontal biofilms can significantly improve via four sides of irradiation. In conclusion, this study not only showed the clinical applicability of this chitosan hydrogel but also the importance of the light irradiation pattern in performing PDI for periodontal disease.

Highlights

Periodontal disease or periodontitis (PD) is an inflammatory disease of the gingival tissue induced by bacteria residing in the plaque biofilm on the subgingival tooth surface
We have shown that a chitosan-based hydrogel containing toluidine blue O (TBO) could exert synergetic photodynamic inactivation (PDI) efficacy [29]
We adjusted the hydroxypropyl methylcellulose (HPMC) concentration to increase the mucoadhesive property of this chitosan hydrogel

Summary

Introduction

Periodontal disease or periodontitis (PD) is an inflammatory disease of the gingival tissue induced by bacteria residing in the plaque biofilm on the subgingival tooth surface. Antimicrobial photodynamic inactivation (PDI) as a bactericide employs the nontoxic PS and light irradiation to generate cytotoxic species, which have toxic effects that cause microbial cell death [10] Many organisms, both bacterial and fungal, found within the flora of the oral cavity have demonstrated susceptibility to various photodynamic treatment regimens In Vitro and In Vivo [11,12,13,14]. Most PDI studies against periodontal bacteria have only employed planktonic cells or biofilms grown in acrylic disks immersed in broth [19] These PDI studies cannot adequately reflect the situations in the oral cavity, the gingival tissue [20]. Our studies showed that microbial biofilm grown on this 3D gingival model provides a more accurate experimental platform for examining the efficacy of photosensitizer formulation as well as modulating light delivery in performing PDI against periodontal infections

Mucoadhesion Studies of Chitosan Hydrogel

Chitosan Hydrogel-Mediated PDI in Biofilm Cells

Statistics Analysis

Conclusions