Photoinactivation of multispecies cariogenic biofilm mediated by aluminum phthalocyanine chloride encapsulated in chitosan nanoparticles.

This study aimed to characterize the aluminum phthalocyanine chloride (AlClPc) encapsulated in chitosan nanoparticles (CN) and apply it in antimicrobial photodynamic therapy (aPDT) on multispecies biofilm composed of Streptococcus mutans, Lactobacillus casei, and Candida albicans to analyze the antimicrobial activity and lactate production after treatment. Biofilms were formed in 24-well polystyrene plates at 37 °C for 48 h under microaerophilia. The following groups were evaluated (n = 9): as a positive control, 0.12% chlorhexidine gluconate (CHX); phosphate-buffered saline (PBS) as a negative control; 2.5% CN as release vehicle control; the dark toxicity control of the formulations used (AlClPc and AlClPc + CN) was verified in the absence of light; for aPDT, after 30 min incubation time, the photosensitizers at a final concentration of 5.8 × 10-3 mg/mL were photoirradiated for 1 min by visible light using a LED device (AlClPc + L and AlClPc + CN + L) with 660 nm at the energy density of 100 J/cm2. An in vitro kit was used to measure lactate. The biofilm composition and morphology were observed by scanning electron microscopy (SEM). The antimicrobial activity was analyzed by quantifying colony forming units per mL (CFU/mL) of each microorganism. Bacterial load between groups was analyzed by ANOVA and Tukey HSD tests (α = 0.05). A lower lactate dosage was observed in the aPDT AlClPc + CN + L and CHX groups compared to the CN and AlClPc groups. The aPDT mediated by the nanoconjugate AlClPc + CN + L showed a significant reduction in the viability of S. mutans (3.18 log10 CFU/mL), L. casei (4.91 log10 CFU/mL), and C. albicans (2.09 log10 CFU/mL) compared to the negative control PBS (p < 0.05). aPDT using isolated AlClPc was similar to PBS to the three microorganisms (p > 0.05). The aPDT mediated by the nanoconjugate AlClPc + CN + L was efficient against the biofilm of S. mutans, L. casei, and C. albicans.

Conjugate of chitosan nanoparticles with chloroaluminium phthalocyanine: Synthesis, characterization and photoinactivation of Streptococcus mutans biofilm.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) using chloroaluminium phthalocyanine (ClAlPc) has high oxidative power allowing for the control of biofilms, especially when the photosensitizer is administered in an appropriate release vehicle. This study aimed to develop/characterize the ClAlPc encapsulated in chitosan nanoparticles (CSNPs), and evaluate its antimicrobial properties against S. mutans biofilms. METHODS: CSNPs were prepared by ion gelation, and characterization studies included particle size, polydispersion index (IPd), zeta potential, accelerated stability, absorption spectrum and ClAlPc quantification. The S. mutans biofilms were formed in bovine dentin blocks at 37 °C for 48 h under microaerophilic conditions. 8 µM ClAlPc was combined with a diode laser (InGaAlP) at 660 nm and 100 J/cm2. The aPDT toxicity was verified by dark phototoxicity. The antimicrobial activity was verified by CFU/mL and biofilm was analyzed by scanning electron microscopy (SEM). The number of viable bacteria was analyzed by ANOVA and Tukey HSD tests (α = 0.05). RESULTS: The characterization revealed that the ClAlPc nanoparticles were found in nanometer-scale with adequate photophysical and photochemical properties. The aPDT mediated by ClAlPc + CSNPs nanoconjugate showed a significant reduction in the viability of S. mutans (1log10 CFU/mL) compared to the negative control (PBS, p < 0.05). The aPDT mediated by ClAlPc was similar to PBS (p > 0.05). SEM revealed change in biofilm morphology following the treatment of bacteria with aPDT ClAlPc + CSNPs. Cells were arranged as single or in shorted chains. Irregular shapes of S. mutans were found. CONCLUSION: ClAlPc nanoparticles are considered stable and aPDT mediated by ClAlPc + CSNPs nanoconjugate was effective against S. mutans biofilm.

Effect of curcumin-mediated photodynamic therapy on Streptococcus mutans and Candida albicans: A systematic review of in vitro studies.

BACKGROUND: There is still no systematized evidence in the literature regarding the combination of curcumin to improve the effects of antimicrobial photodynamic therapy (aPDT) on complex oral biofilms. Therefore, the objective of this review was to systematically assess the antimicrobial effect of curcumin-mediated aPDT on the vitality of biofilms of microorganisms Streptococcus mutans and Candida albicans. METHODS: The addressed focused question was: "What are the effects of curcumin-mediated antimicrobial therapy on the biofilm viability of Streptococcus mutans and Candida albicans in vitro models?" A literature search was conducted in the electronic databases Pubmed, Web of Science, Scopus, Cochrane Library and Bireme up to April 2019. In vitro studies evaluating the effect of curcumin-mediated antimicrobial photodynamic therapy on S. mutans and C. albicans biofilms were included. RESULTS: From 95 citations, 11 full-text articles were screened and 6 studies were included in this review. Because of the heterogeneity observed in the studies selected, meta-analysis was not possible. CONCLUSIONS: The in vitro studies indicate the potential use of curcumin-mediated aPDT to inactivate microorganisms; Streptococcus mutans and Candida albicans. This survey should be viewed as a starting point for further examinations using standardized parameters to enhance outcomes.