Improved photodynamic action of nanoparticles loaded with indium (III) phthalocyanine on MCF-7 breast cancer cells

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2013-09, Vol.15 (9), p.1-19, Article 1879
• Main Authors: Souto, Carlos Augusto Zanoni, Madeira, Klésia Pirola, Rettori, Daniel, Baratti, Mariana Ozello, Rangel, Letícia Batista Azevedo, Razzo, Daniel, da Silva, André Romero
• Format: Article
• Language: English
• Subjects: Aggregates; Breast; Cellular; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cross-disciplinary physics: materials science; rheology; Encapsulation; Exact sciences and technology; Indium; Inorganic Chemistry; Lasers; Materials Science; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanotechnology; Optical Devices; Optics; Photobleaching; Photonics; Physical Chemistry; Physics; Research Paper; Viability
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-013-1879-8

Indium (III) phthalocyanine (InPc) was encapsulated into nanoparticles of PEGylated poly( d , l -lactide-co-glycolide) (PLGA-PEG) to improve the photobiological activity of the photosensitizer. The efficacy of nanoparticles loaded with InPc and their cellular uptake was investigated with MCF-7 breast tumor cells, and compared with the free InPc. The influence of photosensitizer (PS) concentration (1.8–7.5 μmol/L), incubation time (1–2 h), and laser power (10–100 mW) were studied on the photodynamic effect caused by the encapsulated and the free InPc. Nanoparticles with a size distribution ranging from 61 to 243 nm and with InPc entrapment efficiency of 72 ± 6 % were used in the experiments. Only the photodynamic effect of encapsulated InPc was dependent on PS concentration and laser power. The InPc-loaded nanoparticles were more efficient in reducing MCF-7 cell viability than the free PS. For a light dose of 7.5 J/cm 2 and laser power of 100 mW, the effectiveness of encapsulated InPc to reduce the viability was 34 ± 3 % while for free InPc was 60 ± 7 %. Confocal microscopy showed that InPc-loaded nanoparticles, as well as free InPc, were found throughout the cytosol. However, the nanoparticle aggregates and the aggregates of free PS were found in the cell periphery and outside of the cell. The nanoparticles aggregates were generated due to the particles concentration used in the experiment because of the small loading of the InPc while the low solubility of InPc caused the formation of aggregates of free PS in the culture medium. The participation of singlet oxygen in the photocytotoxic effect of InPc-loaded nanoparticles was corroborated by electron paramagnetic resonance experiments, and the encapsulation of photosensitizers reduced the photobleaching of InPc.