Cytotoxicity of glass ionomer cements containing silver nanoparticles.

BACKGROUND: Some studies have investigated the possibility of incorporating silver nanoparticles (NAg) into dental materials to improve their antibacterial properties. However, the potential toxic effect of this material on pulp cells should be investigated in order to avoid additional damage to the pulp tissue. This study evaluated the cytotoxicity of conventional and resin-modified glass ionomer cements (GIC) with and without addition of NAg. MATERIAL AND METHODS: NAg were added to the materials at two different concentrations by weight: 0.1% and 0.2%. Specimens with standardized dimensions were prepared, immersed in 400 µL of culture medium and incubated at 37°C and 5% CO2 for 48 h to prepare GIC liquid extracts, which were then incubated in contact with cells for 48 h. Culture medium and 0.78% NAg solution were used as negative and positive controls, respectively. Cell viability was determined by MTT and Trypan Blue assays. ANOVA and the Tukey test (α=0.05) were used for statistical analyses. RESULTS: Both tests revealed a significant decrease in cell viability in all groups of resin modified cements (p<0.001). There were no statistically significant differences between groups with and without NAg (p>0.05). The differences in cell viability between any group of conventional GIC and the negative control were not statistically significant (p>0.05). CONCLUSIONS: NAg did not affect the cytotoxicity of the GIC under evaluation. KEY WORDS: Glass ionomer cements, totoxicity, cell culture techniques, nanotechnology, metal nanoparticles.

Immunoblotting analyses using two-dimensional gel electrophoresis of Trypanosoma cruzi excreted-secreted antigens

Formas tripomastigotas de Trypanosoma cruzi excretam/secretam uma complexa mistura de moléculas antigênicas. Essa mistura é chamada trypomastigote excreted-secreted antigens e contém uma banda de massa molecular em torno de 150-160kDa que possui excelente performance para diagnóstico de doença de Chagas em immunoblotting. No presente estudo foi caracterizado parcialmente, por gel bidimensional, a proteína de 150-160kDa pela análise da reatividade de anticorpos de pacientes chagásicos nas diversas fases da doença. Proteínas do trypomastigote excreted-secreted antigens foram separadas por eletroforese de alta resolução em duas dimensões (2D) e submetidas a immunoblotting com soros de pacientes chagásicos e não chagásicos. A proteína de 150-160kDa foi identificada em quatro isoformas com pontos isoelétricos variando entre 6,2 a 6,7. As quatro isoformas foram reconhecidas por anticorpos IgM na fase aguda e por anticorpos IgG na fase crônica da doença de Chagas. A isoforma de 150-160kDa, com ponto isoelétrico de aproximadamente 6,4 tornou-se imunodominante dentre as demais com a progressão da doença. Não foi detectada reatividade cruzada com os soros de pacientes não chagásicos ou pacientes infectados com Leishmania sp. Os dados obtidos nesse trabalho, reforçam a importância da utilização do trypomastigote excreted-secreted antigens para o diagnóstico sorológico da doença de Chagas.

Immunoblotting analyses using two-dimensional gel electrophoresis of Trypanosoma cruzi excreted-secreted antigens.

Trypanosoma cruzi trypomastigotes excrete-secrete a complex mixture of antigenic molecules. This antigenic mixture denominated trypomastigote excreted-secreted antigens contains a 150-160 kDa band that shows excellent performance in Chagas' disease diagnosis by immunoblotting. The present study partially characterized by two-dimensional gel electrophoresis the immunoreactivity against the 150-160 kDa protein using sera samples from chagasic patients in different phases of the disease. Trypomastigote excreted-secreted antigen preparations were subjected to high-resolution two-dimensional (2D) gel electrophoresis followed by immunoblotting with sera from chagasic and non-chagasic patients. The 150-160 kDa protein presented four isoforms with isoelectric focusing ranging from 6.2 to 6.7. The four isoforms were recognized by IgM from acute phase and IgG from chronic phase sera of chagasic patients. The 150-160 kDa isoform with IF of approximately 6.4 became the immunodominant spot with the progression of the disease. No cross-reactivity was observed with non-chagasic or patients infected with Leishmania sp. In this study we provide basic knowledge that supports the validation of trypomastigote excreted-secreted antigens for serological diagnosis of Chagas' disease.