Visible Light Activation for Fungal Biofilm Inhibition: Combining Antimicrobial Photodynamic Therapy with Singlet Oxygen and Iodine Generation against Candida albicans and Pichia kudriavzevii Gabriela de Souza Calvi, Marilia Toledo Braga, Giulia Nicolle Jácome Cartaxo, Pavel Kubát, Vojtěch Liška, Jiří Mosinger, Maricilia Silva Costa ACS Omega, 2026 Biofilms formed by Candida albicans and the highly resistant Pichia kudriavzevii are critical virulence factors because of their resistance to conventional antifungals. This study explored antimicrobial photodynamic therapy (aPDT) using sulfonated polystyrene nanoparticles with an encapsulated tetraphenylporphyrin photosensitizer (TPP-NPs), synergistically enhanced by potassium iodide (KI), to combat biofilms of these yeasts. TPP-NPs irradiated by visible light generate antimicrobial singlet oxygen (O2(1Δg)), which oxidizes KI to form another reactive species (I2/I3–), augmenting total antimicrobial effects. The usage of TPP-NPs led to reduced cell proliferation and biofilm viability in both species, with KI significantly enhancing efficacy and enabling lower TPP-NP doses. P. kudriavzevii biofilms were more susceptible (70–80% inhibition, up to 95% with KI) than C. albicans biofilms (30–40% inhibition), a crucial finding for drug-resistant P. kudriavzevii. This is the first demonstration that aPDT using TPP-NPs effectively reduces both biofilm formation and viability, especially against resistant P. kudriavzevii, highlighting its potential as a biocompatible alternative therapy for biofilm-associated infections.
(PhSe)2 and (pCl-PhSe)2 organochalcogen compounds inhibit Candida albicans adhesion to human endocervical (HeLa) cells and show anti-biofilm activities Bruna Marques da Silva, Marília Toledo Braga, Juliene Cristina da Silva Passos, Moisés Lopes Carvalho, Isabela Bueno Rosseti, Laís Mayara Machado de Amorim, João Batista Teixeira da Rocha, Carlos Alberto-Silva, Maricilia Silva Costa Biofouling, 2021 Adhesion capacity on biological surfaces and biofilm formation is considered an important step in the infection process by Candida albicans. The ability of (PhSe)2 and (pCl-PhSe)2, two synthetic organic selenium (organochalcogen) compounds, to act on C. albicans virulence factors related to adhesion to human endocervical (HeLa) cell surfaces and their anti-biofilm activities was analyzed. Both organochalcogen compounds inhibited C. albicans adhesion to HeLa cells, dependent on compound concentrations. (PhSe)2 (at 20 µM; p = 0.0012) was significantly more effective than (pCl-PhSe)2 (at 20 µM; p = 0.0183) compared with the control. (PhSe)2 inhibited biofilm formation and decreased biofilm viability in both early and mature biofilms more efficiently than (pCl-PhSe)2. Overall, the organochalcogen compounds, especially (PhSe)2, were demonstrated to be effective antifungal drugs against C. albicans virulence factors related to epithelial cell surface adhesion and the formation and viability of biofilms.
The organochalcogen compound (Meophse) 2 inhibits both formation and the viability of the biofilm produced by candida albicans, at different stages of development Lais M. Machado de Amorim, Marília T. Braga, Moisés L. Carvalho, Ivone Regina de Oliveira, Samyr M. Querobino, Carlos Alberto-Silva, João B. Teixeira da Rocha, Maricilia S. Costa Current Pharmaceutical Design, 2018 BACKGROUND: Candida albicans is a commensal and opportunistic fungus which is able to produce both local and systemic infections in immunocompromised patients. A correlation has been demonstrated between the resistance to conventional antifungal drugs and C. albicans ability to produce biofilms. Therefore, the potential of the organochalcogen compounds as antifungal therapy has been demonstrated. METHOD: In this work, we studied the effect of the organochalcogen compound (MeOPhSe)2 on both formation and the viability of the biofilm produced by C. albicans, at different stages of development. Biofilm formation and viability were determined by a metabolic assay based on the reduction of XTT assay. In addition, the morphology of the biofilm was observed using light microscopy. RESULTS: A significant reduction was observed in both growth and biofilm formation by C. albicans, in a dependent manner of cell density. In the presence of 2 µM (MeOPhSe)2 it was observed an inhibition of 87, 72, 69 and 56 % in C. albicans growth, using cell densities of 104, 105, 106 and 107 cells/mL, respectively. C. albicans growth was inhibited >90 % in the presence of 10 µM (MeOPhSe)2 in all cell densities used. Also, (MeOPhSe)2 was found to be able to decrease the viability of the biofilm produced by C. albicans at different stages of development. This effect was more pronounced in early biofilms as compared to mature biofilms. Biofilms forming at 6 and 12 hours was inhibited ~80% in the presence of 10 µM (MeOPhSe)2. However, mature biofilms presented an inhibition of ~40 % in the presence of 10 µM (MeOPhSe)2. The analyses of the structure of the biofilm have shown a significant reduction in the number of both yeast and filamentous form after treatment with (MeOPhSe)2. In addition, the organochalcogen compound (MeOPhSe)2 did not modify the viability of Fibroblastic cells. CONCLUSION: Taken together, these results demonstrated the potential of the organochalcogen compound (MeOPhSe) 2 as a promising antifungal therapy.
