Chlorin-e6 conjugated to the antimicrobial peptide LL-37 loaded nanoemulsion enhances photodynamic therapy against multi-species biofilms related to periodontitis.

In our previous studies, Chlorin-e6 (Ce6) demonstrated a significant reduction of microorganisms' viability against multi-species biofilm related to periodontitis while irradiated with blue light. However, the conjugation of Ce6 and antimicrobial peptides, and the incorporation of this photosensitizer in a nanocarrier, is still poorly explored. We hypothesized that chlorin-e6 conjugated to the antimicrobial peptide LL-37 loaded nanoemulsion could inhibit a multi-species biofilm related to periodontitis during photodynamic therapy (PDT), the pre-treatment with hydrogen peroxide was also tested. The nanoemulsion (NE) incorporated with Ce6 was characterized regarding the physiochemical parameters. Images were obtained by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Later, the Ce6 and LL-37 incorporated in NE was submitted to UV-Vis analysis and Reactive Oxygen Species (ROS) assay. Finally, the combined formulation (Ce6+LL-37 in nanoemulsion) was tested against multi-species biofilm related to periodontitis. The formed nanoformulation was kinetically stable, optically transparent with a relatively small droplet diameter (134.2 unloaded and 146.9 loaded), and weak light scattering. The NE system did not impact the standard UV-VIS spectra of Ce6, and the ROS production was improved while Ce6 was incorporated in the NE. The combination of Ce6 and LL-37 in NE was effective to reduce the viability of all bacteria tested. The treatment with hydrogen peroxide previous to PDT significantly impacted bacterial viability. The current aPDT regimen was the best already tested against periodontal biofilm by our research team. Our results suggest that this combined protocol must be exploited for clinical applications in localized infections such as periodontal disease. - Nanoemulsion demonstrated to be an excellent nanocarrier for photodynamic application. - Chlorin-e6 incorporated in nanoemulsion showed great physicochemical and biophotonic parameters. - The combination of chlorin-e6 and LL-37 peptide in nanoemulsion is effective to eliminate periodontal pathogenic bacteria. - The treatment with hydrogen peroxide previous to PDT significantly impacted bacterial viability.

Photodynamic inactivation using a chlorin-based photosensitizer with blue or red-light irradiation against single-species biofilms related to periodontitis.

Chlorin-e6 (Ce6), as a photosensitizer (PS), has demonstrated significant reduction of microorganisms' viability when irradiated by red light. However, the main absorption peak of this PS is located at blue light spectrum, which is less investigated. This study aimed to evaluate the effect of pure-chlorin-e6-mediated photodynamic inactivation (PDI) using different light sources (450 or 660 nm) against biofilms related to periodontitis. Streptococcus oralis, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans single-species biofilms were developed under proper conditions for five days. PDI was performed using different concentrations of Ce6 (100 and 200 mM), wavelengths (450 and 660 nm) and comparisons were made after colony forming unit and confocal laser scanning microscopy (CLSM) analysis. The use of light and PS were also individually tested. The greatest bacterial elimination was observed in the group where PDI was employed with blue light and concentration of 200 mM for all bacterial strains tested (4.01 log10 for A. actinomycetemcomitans, and total elimination for P. gingivalis and S. oralis), except for F. nucleatum, where 3.46 log10 reduction was observed when red light and 200 mM Ce6 were applied (p < 0.05). The antimicrobial effects of PDI mediated by Ce6 for all single pathogenic biofilms were confirmed by live/dead staining under CLSM analysis. For all single-species biofilms, the use of PDI mediated by chlorin-e6 photosensitizer under blue or red-light irradiation (450 and 660 nm) demonstrated a significant reduction in bacterial viability, but blue light showed a promising higher photobiological effect, encouraging its adjuvant use to basic periodontitis treatment.

Antimicrobial photodynamic therapy associated with bone regeneration for peri-implantitis treatment: A case report.

Antimicrobial photodynamic therapy (aPDT) has emerged as a promising alternative to promote bacterial elimination and crestal bone remodeling in patients affected by peri-implantitis, once it is able to access the implant microstructure at the most restricted sites with no damage to implant surface. This paper reports a 6-month follow-up of a patient with peri-implantitis treated by surgical approach with adjunct photodynamic therapy associated to guided bone regeneration. A full thickness open-flap was performed to allow directly mechanical debridement, followed by aPDT using methylene blue 200 µg/mL under red laser irradiation (660 nm, 100 mW, 9 J), providing decontamination of implant surface and surrounding tissue. Photosensitizer was washed twice with saline solution previously to guided bone regeneration, which was carried out using xenogeneic bone and resorbable collagen membrane. After 6-month follow-up, the use of aPDT as an adjunct therapy to the surgical treatment of peri-implantitis promoted sufficient decontamination, clear evidence of bone regeneration, and peri-implant health restoration.

Surgical Treatment of Implants Affected by Periimplantitis After 15 Years of Loading: A Case Report.

PURPOSE: The aim of this case report is to describe the surgical treatment of 2 implants affected by periimplantitis after 15 years of loading. MATERIALS AND METHODS: The treatment included mechanical and chemical decontamination with topical application of tetracycline associated with a regenerative approach. Both defects were filled with particulate autogenous bone from tuber and covered with resorbable collagen membrane. RESULTS: The follow-up of 30 and 13 months of the implants 24 and 14, respectively, showed an absence of clinical signs of periimplant inflammation and near-complete bone regeneration. CONCLUSIONS: The therapy approach was effective in eliminating periimplant inflammation and promoting bone gain around the implants.