Antimicrobial photodynamic therapy mediated by methylene blue coupled to β-cyclodextrin reduces early colonizing microorganisms from the oral biofilm

Postbiotic mediators derived from Lactobacillus species enhance riboflavin-mediated antimicrobial photodynamic therapy for eradication of Streptococcus mutans planktonic and biofilm growth

BACKGROUND

Streptococcus mutans has been implicated as a primary causative agent of dental caries and one of its important virulence properties is an ability to form biofilm on tooth surfaces. Thus, strategies to prevent and control S. mutans biofilms are requested. The present study aimed to examine the eradication of S. mutans planktonic and biofilm cells using riboflavin (Rib)-mediated antimicrobial photodynamic therapy (aPDT) enhanced by postbiotic mediators derived from Lactobacillus species.

MATERIALS AND METHODS

Minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of Rib and postbiotic mediators were determined. The antimicrobial and anti-biofilm effects of Rib-mediated aPDT (Rib plus blue light), Rib-mediated aPDT in combination with postbiotic mediators derived from Lactobacillus casei (LC) (aPDT+ LC), and Rib-mediated aPDT in combination with postbiotic mediators derived from Lactobacillus plantarum (LP) (aPDT+ LP) were evaluated. The anti-virulence potential of Rib-mediated aPDT, aPDT+ LC, and aPDT+ LP were assessed by measuring the expression of the gtfB gene using quantitative real-time polymerase chain reaction (qRT-PCR) at the highest concentrations of Rib, LC, and LP, at which the S. mutans had proliferation as the same as in the control (non-treated) group.

RESULTS

According to the results, the MIC doses of LC, LP, and Rib were 64 µg/mL, 128 µg/mL, and 128 µg/mL, respectively, while the MBC values of LC, LP, and Rib were 128 µg/mL, 256 µg/mL, and 256 µg/mL, respectively. Rib-mediated aPDT, aPDT+ LP, and aPDT+ LC showed a significant reduction in Log10 CFU/mL of S. mutans compared to the control group (4.2, 4.9, and 5.2 Log10 CFU/mL, respectively; all P < 0.05). The most destruction of S. mutans biofilms was observed after treatment with aPDT+ LC followed by aPDT+ LP and Rib-mediated aPDT (77.5%, 73.3%, and 67.6%, respectively; all P < 0.05). The concentrations of 31.2 µg/mL, 62.5 µg/mL, and 62.5 µg/mL were considered as the highest concentrations of LC, LP, and Rib, respectively, at which S. mutans replicates as same as the control group and were used for gtfB gene expression assay using qRT-PCR during Rib-mediated aPDT, aPDT+ LP, and aPDT+ LC treatments. Gene expression results revealed that aPDT+ LP and aPDT+ LC could decrease the gene expression level of gtfB by 6.3- and 5.7-fold, respectively (P < 0.05), while only 5.1-fold reduction was observed after Rib-mediated aPDT (P < 0.05).

CONCLUSION

Our findings indicate that aPDT+ LP and aPDT+ LC hold promise for use as a treatment to combat S. mutans planktonic and biofilms growth as well as anti-virulence as a preventive strategy to inhibit biofilms development via reduction of gtfB gene expression.

Recent updates and feasibility of nanodrugs in the prevention and eradication of dental biofilm and its associated pathogens-A review

OBJECTIVES

Dental biofilm is one of the most prevalent diseases in humans, which is mediated by multiple microorganisms. Globally, half of the human population suffers from dental biofilm and its associated diseases. In recent trends, nano-formulated drugs are highly attractive in the treatment of dental biofilms. However, the impact of different types of nanodrugs on the dental biofilm and its associated pathogens have not been published till date. Thus, this review focuses on the recent updates, feasibility, mechanisms, limitations, and regulations of nanodrugs applications in the prevention and eradication of dental biofilm.

STUDY SELECTION, DATA AND SOURCES

A systematic search was conducted in PubMed/Google Scholar/Scopus over the past five years covering the major keywords "nanodrugs, metallic nanoparticles, metal oxide nanoparticles, natural polymers, synthetic polymers, biomaterials, dental biofilm, antibiofilm mechanism, dental pathogens", are reviewed in this study. Nearly, 100 scientific articles are selected in this relevant topic published between 2019 and 2023. Data from the selected studies dealing with nanodrugs used for biofilm treatment was qualitatively analyzed.

CONCLUSIONS

The nanodrugs such as silver nanoparticles, gold nanoparticles, selenium nanoparticles, zinc oxide nanoparticles, copper oxide nanoparticles, titanium oxide nanoparticles, hydroxyapatite nanoparticles and these inorganic nanoparticles incorporated polymer-based nanocomposites, organic/inorganic nanoparticles mediated antimicrobial photodynamic therapy exhibits an excellent antibacterial and antibiofilm activity towards dental pathogens. Finally, this review highlights that bioinspired nanodrugs will be very useful to control the dental biofilm and its associated diseases.

CLINICAL SIGNIFICANCE

Microbial influence on the oral environment is unavoidable; therefore, curing such dental biofilms and pathogens is essential for the impactful reflection of applying biocompatible treatments. In this direction, the current review explains the demand for the nanodrug in inhibiting biofilms for the effective exploration of employing treatments.

Antimicrobial photodynamic therapy for the treatment of oral infections: A systematic review

Oral infection is a common clinical symptom. While antibiotics are widely employed as the primary treatment for oral diseases, the emergence of drug-resistant bacteria has necessitated the exploration of alternative therapeutic approaches. One such modality is antimicrobial photodynamic therapy (aPDT), which utilizes light and photosensitizers. Indeed, aPDT has been used alone or in combination with other treatment options dealing with periodontal disease for the elimination of biofilms from bacterial community to achieve bone formation and/or tissue regeneration. In this review article, in addition to factors affecting the efficacy of aPDT, various photosensitizers, the latest technology and perspectives on aPDT are discussed in detail. More importantly, the article emphasizes the novel design and clinical applications of photosensitizers, as well as the synergistic effects of chemical and biomolecules with aPDT to achieve the complete eradication of biofilms and even enhance the biological performance of tissues surrounding the treated oral area.

Investigation on the effect of antimicrobial photodynamic therapy as an adjunct for management of deep caries lesions-study protocol for a randomized, parallel groups, controlled clinical trial

BACKGROUND

Alternatively to conventional treatments, chemo-mechanical caries removal agents can be used. A modality of treatment that has been increasing in dentistry is antimicrobial photodynamic therapy (aPDT). Bixa orellana is being researched for application in aPDT. This protocol aims to determine the effectiveness of aPDT with Bixa orellana extract in deep caries lesions.

METHODS

A total of 160 teeth with deep occlusal dental caries will be selected and divided into 4 groups: G1 - control group (Caries removal with a low-speed drill); G2 - Partial Caries Removal with Papacarie™ (Fórmula e Ação, São Paulo, SP, Brazil); G3 - Partial Caries Removal with Papacarie™ and application Bixa orellana extract (20%) (Fórmula e Ação, São Paulo, SP, Brazil); G4 - Partial Caries Removal with Papacarie™ and application Bixa orellana extract (20%) with LED (Valo Cordless Ultradent®, South Jordan, UT, USA) (aPDT). After treatment, all the teeth will be restored with glass ionomer cement and followed up clinically and radiographically, with evaluations at immediately, 1 week, and 1, 3, 6, and 12 months. Dentin samples before and after treatment will be analyzed microbiologically. The efficacy of treatments will be assessed with microbiological (colony-forming units, before and after carious tissue removal), radiographic (integrity of the periapical area and eventual changes in the radiolucent zones), and clinical examinations (retention of the restorative material in the cavity and occurrence of secondary caries), as well as with the time required for the procedures and the need for anesthesia during the procedures. In case data distribution is normal, analysis of variance (ANOVA) will be used for both the dependent and independent variables. In case the data distribution is not normal, the Friedman test will be used for the dependent variables. For independent variables, the Kruskal-Wallis test will be used.

DISCUSSION

Procedures using aPDT have been developed for the treatment of dental caries, but there are few controlled clinical trials in the literature confirming its efficacy.

TRIAL REGISTRATION

This protocol is registered at ClinicalTrials.gov under the number NCT05236205 and it was first posted on 01/21/2022 and last updated on 05/10/2022.

Application of Nano-Inspired Scaffolds-Based Biopolymer Hydrogel for Bone and Periodontal Tissue Regeneration

This review's objectives are to provide an overview of the various kinds of biopolymer hydrogels that are currently used for bone tissue and periodontal tissue regeneration, to list the advantages and disadvantages of using them, to assess how well they might be used for nanoscale fabrication and biofunctionalization, and to describe their production processes and processes for functionalization with active biomolecules. They are applied in conjunction with other materials (such as microparticles (MPs) and nanoparticles (NPs)) and other novel techniques to replicate physiological bone generation more faithfully. Enhancing the biocompatibility of hydrogels created from blends of natural and synthetic biopolymers can result in the creation of the best scaffold match to the extracellular matrix (ECM) for bone and periodontal tissue regeneration. Additionally, adding various nanoparticles can increase the scaffold hydrogel stability and provide a number of biological effects. In this review, the research study of polysaccharide hydrogel as a scaffold will be critical in creating valuable materials for effective bone tissue regeneration, with a future impact predicted in repairing bone defects.

Application of sonodynamic technology and sonosensitizers in food sterilization: a review of developments, trends and challenges

Food safety and food waste have always been hot topics of discussion in recent years. However, the infection of human pathogenic bacteria and the waste of food resources caused by microbial-contaminated food remains common. Although traditional sterilization technology has been very mature, it causes changes in food flavor and excessive energy consumption to a certain extent. Moreover, the widespread bacterial resistance has also sounded a warning for researchers and finding a new alternative to antibiotics is urgently needed. The application of sonodynamic sterilization technology in medical treatment has aroused the interest of researchers. It provides ideas for new food sterilization technology. As a new non-thermal sterilization technology, sonodynamic sterilization technology has strong penetration, safety, less residue and by-products, and will less change the quality of the food itself. Therefore, sonodynamic sterilization technology has great potential applied in food sterilization technology. This review describes the concept of sonodynamic sterilization technology, the sterilization mechanism of sonodynamic sterilization and the inactivation mechanism of various pathogens, the classification and application of sonosensitizers, and the ultrasonic technology in sonodynamic sterilization in the application over the recent years. It provides a scientific reference for the application of sonodynamic sterilization technology in the field of food sterilization.

Potassium iodide enhances inactivation of Streptococcus mutans biofilm in antimicrobial photodynamic therapy with red laser

OBJECTIVE

To evaluate the effect of potassium iodide (KI) addition on antimicrobial photodynamic therapy (aPDT) mediated by red laser (λ = 660 nm) and methylene blue in Streptococcus mutans biofilm model.

METHODS

S. mutans biofilms were cultured in 96-well plates containing BHI broth with 1% sucrose for 18 h, 10% CO₂ and 37°C and divided in groups (n = 3, in triplicate): C (NaCl 0.9%); CX (0.2% chlorhexidine); P (photosensitizer); KI (10, 25 and 50 mM); PKI (10, 25 and 50 mM); L (L 1: : 100 J/cm², 9 J; L2: 200 J/cm², 18 J); PL (photosensitizer + L1 or L2); KIL (KI at 10, 25 and 50 mM + L1 or L2); and PKIL (photosensitizer + 10, 25 and 50 mM KI + L1 or L2). Biofilms were submitted to three pre-irradiation (PI) times (5, 10, and 15 min). After the treatments, microbial counting's reduction was analyzed by Kruskal-Wallis and post-hoc Dunn's tests, respectively, and the interaction between light parameters and the PI times by two-way ANOVA (p < 0.05).

RESULTS

The S. mutans viability significantly reduced in all aPDT groups, in the presence or absence of KI (p < 0.05). For all PI times, PKIL groups (10, 25, and 50 mM) significantly differed from PL groups (p < 0.05) with a reduction of 9.0 logs reached at 50 mM of KI with 15 min of PI, irradiated at 18 J. We found no significant interaction between PI time and irradiation (p > 0.05).

CONCLUSION

Addition KI to TFDA mediated by methylene blue and red laser promoted an additional effect in reducing the microbial viability of S. mutans biofilm.

Exploration on the Enhancement of Detoxification Ability of Zearalenone and Its Degradation Products of Aspergillus niger FS10 under Directional Stress of Zearalenone

Zearalenone (ZEN) is one of the most common mycotoxin contaminants in food. For food safety, an efficient and environmental-friendly approach to ZEN degradation is significant. In this study, an Aspergillus niger strain, FS10, was stimulated with 1.0 μg/mL ZEN for 24 h, repeating 5 times to obtain a stressed strain, Zearalenone-Stressed-FS10 (ZEN-S-FS10), with high degradation efficiency. The results show that the degradation rate of ZEN-S-FS10 to ZEN can be stabilized above 95%. Through metabolomics analysis of the metabolome difference of FS10 before and after ZEN stimulation, it was found that the change of metabolic profile may be the main reason for the increase in the degradation rate of ZEN. The optimization results of degradation conditions of ZEN-S-FS10 show that the degradation efficiency is the highest with a concentration of 10⁴ CFU/mL and a period of 28 h. Finally, we analyzed the degradation products by UPLC-q-TOF, which shows that ZEN was degraded into two low-toxicity products: C₁₈H₂₂O₈S (Zearalenone 4-sulfate) and C₁₈H₂₂O₅ ((E)-Zearalenone). This provides a wide range of possibilities for the industrial application of this strain.