Photodynamic action of gallium phthalocyanine encapsulated in polymeric nanoparticles on the viability of gastric tumor cells (GTC) and Candida auris.
Name: MATEUS SOUZA ALVARENGA
Publication date: 30/04/2026
Examining board:
Name |
Role |
|---|---|
| ANDRE ROMERO DA SILVA | Presidente |
| HILDEGARDO SEIBERT FRANÇA | Examinador Externo |
| JAIRO PINTO DE OLIVEIRA | Coorientador |
| JULIANA BARBOSA COITINHO GONCALVES | Examinador Interno |
Summary: Gastric cancer and the fungus Candida auris and candidiasis caused by the fungus are diseases characterized by late diagnosis and difficult-to-administer treatment, exhibiting alarming virulence and lethality. Aiming for greater efficacy in treating these diseases, photodynamic therapy has shown promise because it does not require continuous use of medication, particularly when combined with metal phthalocyanines due to their therapeutic potential. This technique uses a photosensitizer that, when exposed to a specific wavelength of light in the presence of oxygen, generates reactive oxygen species leading to cell death. The present study was structured in stages involving the synthesis, characterization, and optimization of the nanoparticles, as well as a preliminary analysis of their physicochemical and photodynamic properties. A full 2 factorial design was performed to investigate the effects of polymer type, emulsifier, rotor, and photosensitizer. Subsequently, an optimized 2³ factorial design was conducted to refine the process, exploring the influence of polymer mass, emulsifier concentration, and stirring speed. The analyses showed that the formulations containing PLGA-PEG and Poloxamer®188 yielded nanoparticles with a size of 108 nm and an encapsulation efficiency of 95.35%. The micrographs obtained by transmission electron microscopy confirmed a spherical morphology and sizes within the expected nanometer range. Photooxidation assays with tryptophan and albumin demonstrated that irradiation of the system containing free and encapsulated GaPc progressively reduced the fluorescence of the biomolecules (23.8% and 11.05%), (24.37% and 12.11%), demonstrating potential for the induction of fungal cell death. The results of applications on gastric cancer cells and Candida auris also showed that the technique is promising for the effective treatment of these diseases, reducing cell viability by 50% and 85%, respectively. The results indicate that the developed system shows promising potential for application in photodynamic therapy for the treatment of gastric cancer and resistant fungal infections.
