Antimicrobial Photoinactivation of In Situ Oral Biofilms by Visible Light Plus Water-Filtered Infrared A and Tetrahydroporphyrin-tetratosylate (THPTS)

Abstract

The aim of this study was to examine the effect of aPDT with visual light (VIS) + water-filtered infrared A (wIRA) as a light source, and tetrahydroporphyrin-tetratosylate (THPTS) as a photosensitizer on in situ initial and mature oral biofilms. The samples were incubated, ex situ, with THPTS for two minutes, followed by irradiation with 200 mW cm − 2 VIS + wIRA for five minutes at 37 °C. The adherent microorganisms were quantified, and the biofilm samples were visualized using live/dead staining and confocal laser scanning microscopy (CLSM). The THPTS-mediated aPDT resulted in significant decreases in both the initially adherent microorganisms and the microorganisms in the mature oral biofilms, in comparison to the untreated control samples (>99.99% each; p = 0.018 and p = 0.0066, respectively). The remaining vital bacteria significantly decreased in the aPDT-treated biofilms during initial adhesion (vitality rate 9.4% vs. 71.2% untreated control, 17.28% CHX). Of the mature biofilms, 25.67% remained vital after aPDT treatment (81.97% untreated control, 16.44% CHX). High permeability of THPTS into deep layers could be shown. The present results indicate that the microbial reduction in oral initial and mature oral biofilms resulting from aPDT with VIS + wIRA in combination with THPTS has significant potential for the treatment of oral biofilm-associated diseases.

The antimicrobial effect of Rosmarinus officinalis extracts on oral initial adhesion ex vivo

“…A dilution series with 0.9% NaCl was then prepared for each sample up to a dilution of 1:10 3 and 1:10 4 . The bacterial species were subsequently cultured and identified as previously described [37]. A 100-µl aliquot of each sample and dilution was plated onto one HCB plate and one CBA plate using a sterile glass spatula.…”

Biodentine Inhibits the Initial Microbial Adhesion of Oral Microbiota In Vivo

“…The CFUs were quantified as described in detail earlier [53]. In brief, after exposure in the oral cavity, the specimens were rinsed for 10 sec each with 1 mL sterile 0.9% NaCl to remove non-adherent microorganisms.…”

“…Fluorescent propidium iodide (PI) stain was used with the SYTO ® 9 (Live/Dead ® Bac-Light™ Bacterial Viability Kit, Life Technologies GmbH, Darmstadt, Germany) to determine the number of viable and dead bacterial cells [53]. Intact cells and those with disrupted membranes can be penetrated by the green fluorescence stain SYTO ® 9, whereas the red-fluorescent PI can only penetrate disrupted cell membranes.…”

“…All samples were analyzed using FM with a 63 × oil immersion objective (Apo-Tome.2, Zeiss, Oberkochen, Germany). The active and dead cells on the images obtained were quantified using the image analysis program ZEN 2 pro (Zeiss, Oberkochen, Germany), and the coverage rates of the live and dead bacteria were subsequently calculated from the data obtained [53]. The results were also visualized by representative microscopic images that were acquired using a 3-Megapixel Microscope camera (Axiocam 503 mono, ZEISS, Oberkochen, Germany).…”

Antimicrobial Photodynamic Inactivation Using Topical and Superhydrophobic Sensitizer Techniques: A Perspective from Diffusion in Biofilms†

“…Positively charged photosensitizers are attracted to negatively charged microbe and biofilm surfaces, accelerating their diffusion (30,(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43). Other factors that affect Sens diffusion into the biofilm include net charge, charge density, molecular weight, hydrophobicity, hydrogen bonding capability, pH and solubility (44,45). For example, photosensitizers with cationic substituents, when applied to single-species and multispecies biofilms, resulted in up to ~7 log killing, with light doses typically in tens or hundreds of J cm À2 (46-49).…”