Method: Aliquots of C. albicans standardized suspensions were transferred to a microplate and incubated for 90 min for the adhesion phase. After, each well was washed and the plates were incubated for 48 h (37°C) in order to generate single-species biofilms. Fungal biofilms were treated with different types of delivery systems containing ClAlPc at 31.8 μM for 30 min in the dark (cationic or anionic NE or diluted in DMSO). After the pre-incubation period, the drug was removed and saline was added followed by irradiation with LED source (660 ± 3 nm; 50 and 100 J/cm2). Negative control samples were not exposed to ClAlPc or light. The photodynamic effects against the biofilms were also evaluated using the XTT assay (Multiple Comparision Based on Pairwise ranking; α= 0,05%).
Result: Fungal viability was dependent on the delivery system, superficial load and light dose. Cationic NE-ClAlPc in combination with LED decreased biofilm metabolism by 70% when used with 100 J/cm2 (p< 0.05). When illuminated with both 50 and 100 J/cm2 fluences, the free ClAlPc decreased the biofilm metabolism by approximately 26 and 34%, respectively (p< 0.05). Anionic NE-ClAlPc did not present antifungal activity.
Conclusion: ClAlPc entrapped in cationic NE or in its free form combined with LED irradiation presented antifungal potential, characterized by reduction of the metabolic activity of C. albicans biofilms.