Evaluation of adding nanosized natural zeolite to photodynamic therapy against P. gingivalis biofilm on titanium disks.

BACKGROUND: Antibacterial photodynamic therapy (aPDT) can be used as an adjunctive therapy for eliminating bacterial biofilm. The application of nanotechnology in aPDT, which is a growing trend, has improved the delivery of photosensitizers (PSs) into microorganisms. Encapsulation of molecules and ions is considered an outstanding potential feature of zeolites. This study sought to enhance the effect of aPDT using a diode laser (810 nm) with a potential PS, indocyanine green (ICG), combined with nanosized natural zeolite (NZ), against biofilm of P. gingivalis on sandblasted, large-grit, and acid-etched (SLA) implant titanium disks surface. METHODS: A bacterial suspension of standard P. gingivalis (™ATCC® 33277) strains was prepared. To prepare bacterial biofilm, the titanium disks were added to 48 microtubes containing bacterial suspension, and divided into eight groups, i.e., the control groups (positive and negative), and 6 test groups (ICG; NZ; Diod laser; NZ+ICG; aPDT; NZ+aPDT). After the treatments, the total number of colony-forming units per disk was calculated. Finally, the data was analyzed, and the eight groups were compared together. RESULTS: The highest reduction in the number of P. gingivalis was seen in group 8 (NZ+aPDT) with 3.55 log10 CFU/ml and the antibacterial effect of 45.7% compared with the negative control group. Conversley, group 5 (Diode Laser solely) represented the highest mean of colony count with the lowest antibacterial effects per disk (6.42 log10 CFU/ml, 1.8%). CONCLUSIONS: The antibacterial effect of NZ+aPDT against P. gingivalis biofilm was noticeable. Thus, adding NZ to ICG improved the result of aPDT in this study.

Designing and in Silico Analysis of PorB Protein from Chlamydia Trachomatis for Developing a Vaccine Candidate.

Bakground: Chlamydia trachomatis is an obligate, intracellular, gram-negative bacterium that causes sexually transmitted infections. The outer membrane protein PorB is a conserved chlamydial protein that functions as a porin and is a target for neutralizing antibodies (Abs); thus, making it important for vaccine development. Methods: We used an in silico strategy and homology modeling algorithms and focused on PorB of C. trachomatis and explained its characterization with the help of bioinformatic tools to introduce it as a candidate for novel drug and vaccine design. In this study, physicochemical characterization, secondary and 3D structure, and functional site prediction were investigated. Then, a B cell epitope was analyzed using Immune Epitope Database, which predicts the target region and helps in vaccine development. Results: PorB is a surface-exposed protein comprising 340 amino acids and frequently appears (61.76%) as a random coiled structure. PorB was present outside the cell and the maximum length of the predicted epitope was from amino acids 91-108, i. e., 18 amino acids long. This epitope can be considered for designing Abs and vaccines against C. trachomatis. Conclusion: Although many attempts have been made to develop a vaccine against C. trachomatis, no protective vaccines are available to date. More detailed studies focusing on PorB should be performed to design vaccines against C. trachomatis because of the presence of different immunization protocols and requirement of different protective mechanisms.

Sub-lethal doses of photodynamic therapy affect biofilm formation ability and metabolic activity of Enterococcus faecalis.

BACKGROUND: During photodynamic therapy (PDT) in the treatment of a primary endodontic infection, it is extremely likely that microorganisms would be exposed to sub-lethal doses of PDT (sPDT). Although sPDT cannot kill microorganisms, it can considerably influence microbial virulence. This study was conducted to characterize the effect of sPDT using toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) on biofilm formation ability and metabolic activity of Enterococcus faecalis. METHODS: The antimetabolic and antibiofilm potential of ICG-, TBO-, and MB-sPDT against E. faecalis was analyzed at sub-lethal doses (1/2-1/64 minimum inhibitory concentration) using the XTT reduction assay, crystal violet assay, and scanning electron microscopy. RESULTS: Higher doses of sPDT adversely affected biofilm formation ability and metabolic activity. ICG-, TBO-, and MB-PDT at a maximum sub-lethal dose markedly reduced the formation of biofilm up to 42.8%, 22.6%, and 19.5%, respectively. ICG-, TBO-, and MB-sPDT showed a marked reduction in bacterial metabolic activity by 98%, 94%, and 82%, respectively. ICG-PDT showed a stronger inhibitory effect on biofilm formation in E. faecalis than MB- and TBO-PDT at sub-lethal levels. Interestingly, a gradual increase in metabolic activity and biofilm formation upon exposure to a lower dose of test sPDT were observed. CONCLUSION: sPDT showed dual effect on biofilm formation ability and metabolic activity of E. faecalis. High doses revealed antimetabolic and antibiofilm potential activity, whereas lower doses had conflicting results. Hence, when PDT is prescribed in clinical settings, the dose of PDT used in vivo should be taken into consideration.

Evaluation of antimicrobial photodynamic therapy with indocyanine green and curcumin on human gingival fibroblast cells: An in vitro photocytotoxicity investigation.

UNLABELLED: Recent investigations have suggested that antimicrobial photodynamic therapy (aPDT) can be an alternative treatment for the management of periodontal infections. However, currently there is very limited data regarding the photocytotoxicity of this method on human gingival fibroblast (HuGu) cells. AIM: The in vitro optimal concentrations of indocyanine green (ICG) and curcumin as photosensitizers (PSs) and the irradiation time of diode laser emission were evaluated by assessing the photocytotoxicity of the treatment on HuGu cells. MATERIALS AND METHOD: Monolayers of HuGu cells were incubated with various final concentrations of ICG (500, 750, 1000, 1250, 1500, 1750, and 2000µg/ml) and curcumin (3, 4, 5, 10, and 20mM). Three exposure times of the diode laser (30s, 60s, and 2×30s irradiation with an interval of 1min between each) and one of exposure time of 5min for LED were tested; cell viability was determined using neutral red assay. Chlorhexidine (CHX) as a gold standard antimicrobial agent for periodontal disease was considered as a control group. RESULTS: ICG and curcumin significantly reduced HuGu cell viability at concentrations below 1000µg/ml and 10mM, respectively (P<0.01). Cytotoxicity was higher when the cells were treated for 2×30s irradiation with an interval of 1min and then again exposed to the laser for 30s (2% and 0.1%). CHX demonstrated no significant reduction in HuGu cell survival. CONCLUSION: Photocytotoxicity is influenced by PS concentration, exposure time of PS, and time of irradiation. High doses of ICG and curcumin with lowest exposure time of light source and without cytotoxic effects may be an effective strategy for aPDT as an alternative treatment for periodontal disease.

In vitro effect of Sambucus ebulus on scolices of Hydatid cysts.

OBJECTIVES: Echinococcosis infection is caused in humans by the larval stage of cestodes belonging to the genus Echinococcus. Hydatid cyst cured by percutaneous aspiration, infusion of scolicidal agents with reaspiration or surgery. Many scolicidal agents have been used for inactivation of the cyst's content, but most of them are not safe due to their unanticipated side effects. In the present study, the scolicidal effect of methanolic extract of Sambucus (S.) ebulus fruit is investigated. MATERIALS AND METHODS: Protoscolices were aseptically aspirated from sheep livers having hydatid cysts. Four concentrations (1, 10, 50 and 100 mg ml-1) of S. ebulus extract were used for 5, 10, 30 and 60 min. Viability of protoscolices was confirmed by 0.1% Eosin staining. RESULTS: The results of our study indicated that methanolic extract of S. ebulus fruit showed a high scolicidal activity in vitro (p < 0.0001). CONCLUSIONS: Methanolic extract of S. ebulus showed high scolicidal activity in vitro. It might be used as a scolicidal cause in the surgical treatment of the hydatid cyst. However, further research on the in vivo efficacy of S. ebulus extract and its potential side effects is recommended.