This study investigated the targeted antimicrobial effects of three photosensitizers—Rose Bengal (RB), methylene blue (MB), and porphyrin derivative (PD)—in photodynamic therapy (PDT) for the selective inactivation of microbial biofilms on acrylic denture resin surfaces. The research focused on evaluating whether these agents could effectively reduce pathogenic load while preserving the physical integrity of the denture material and minimizing off-target effects. Heat-cured acrylic resin blocks (15 mm × 15 mm × 4 mm) were prepared and inoculated with standard strains of *Streptococcus mutans*, *Staphylococcus aureus*, *Escherichia coli*, and *Candida albicans* to develop mature biofilms over 48 hours. Specimens were then randomly assigned to four groups: Group 1 treated with RB at 5 µM, Group 2 with MB at 500 mg/L, Group 3 with PD at 5 mL, and Group 4 exposed to 0.12% chlorhexidine (CHX) as a control.
Each photosensitizer was applied uniformly across all surfaces prior to irradiation using a light-emitting diode (LED) with specific parameters: RB activated at 480 nm (200 mW, 526 mW/cm²), MB at 530–652 nm (150 mW), and PD at 440–460 nm (24 mW/cm²), each delivered for 180 seconds.198481-33-3 Formula CHX was applied topically for 60 seconds. After treatment, samples were cultured on brain heart infusion agar and Sabouraud dextrose agar, incubated at 37°C for 48 hours, and colony-forming units (CFU/mL) were counted and expressed in log₁₀ values.
The results demonstrated that CHX achieved the most consistent and significant reduction across all tested microorganisms: *E. coli* (2.04 ± 0.07), *C. albicans* (2.09 ± 0.85), *S. aureus* (3.04 ± 0.11), and *S. mutans* (2.54 ± 0.91) CFU/mL (log₁₀). Among PDT agents, RB showed strong activity against Gram-positive bacteria, significantly reducing *S. aureus* (3.62 ± 0.68) and *S. mutans* (3.41 ± 0.13), but had no effect on *E. coli*. MB effectively reduced *E. coli* (3.16 ± 0.34) and *C. albicans* (5.22 ± 0.77), indicating broad-spectrum potential. PD exhibited the highest selectivity for *C. albicans*, achieving a reduction of 3.67 ± 0.18 CFU/mL (log₁₀), suggesting optimal interaction with fungal cell structures.
Statistical analysis revealed that while CHX remained superior in overall efficacy, each photosensitizer displayed distinct patterns of microbial susceptibility.Integrin α5 Antibody In stock RB’s effectiveness against Gram-positive species may be due to its cationic charge and ability to bind to anionic bacterial membranes.PMID:34523106 MB’s performance likely stems from its balanced hydrophilicity and lipophilicity, enabling penetration into both Gram-negative and fungal cells. PD’s high affinity for *C. albicans* is attributed to its structural similarity to endogenous porphyrins, which are preferentially taken up by fungal cells and generate cytotoxic reactive oxygen species upon light activation.
These findings support the use of PDT as a precision-based disinfection strategy in prosthodontics. By matching the photosensitizer to the dominant microbial flora—such as RB for streptococcal infections, MB for mixed Gram-negative and fungal contamination, or PD for candidiasis—clinicians can achieve targeted biofilm control without widespread microbial suppression. However, incomplete eradication in all groups indicates limitations related to biofilm matrix protection, uneven photosensitizer distribution, and insufficient light penetration. Future research should focus on improving delivery systems, enhancing biofilm disruption, and combining PDT with mechanical cleaning methods. This study confirms that RB, MB, and PD are valuable tools for selective microbial inactivation, offering a safe, non-resistant alternative to conventional chemical disinfectants in the management of denture-related oral infections.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
