Estudos biológicos de nanopartículas de óxido de zinco: interação com proteínas e avaliação de “Burst” oxidativo de leucócitos
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Data
2016-03-03
Autores
Pastrello, Bruna [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O óxido de zinco (ZnO) é um semicondutor muito utilizado na área tecnológica, principalmente em dispositivos fotovoltaicos e, mais recentemente, vem sendo utilizado em aplicações biomédicas. Porém, os efeitos citotóxicos, principalmente quando em tamanho nanométrico, associados ao seu uso, não devem ser descartados. Assim, este trabalho teve por objetivo estudar o efeito tempo de sonicação na morfologia de nanopartículas de ZnO e como estas diferenças poderiam afetar a estrutura da albumina, provocar a hemólise de eritrócitos e a ativação de neutrófilos humanos, quando em contato com este material. Amostras de ZnO foi obtido através do método de síntese ultrassônica, caracterizada por métodos ópticos e suas morfologias observadas em microscópio de varredura eletrônica. Foram obtidas duas morfologias distintas: nanoflores e nanoagulhas. Em todos os testes biológicos a concentração final de ZnO foi 0,1mg/mL em todos os experimentos, onde incubou-se o mesmo com albumina humana e com células sanguíneas (eritrócitos e neutrófilos). Não se observou alterações significativas na estrutura da albumina quando incubada com ZnO, como evidenciado por estudos de fluorescência intrínseca e extrínseca. Uma exceção foi uma pequena agregação da proteína quando incubada com o ZnO (nanoflor) avaliado por espalhamento de luz (Rayleigh). Embora pouco efetiva, esta morfologia do ZnO também foi mais eficaz na indução de hemólise de eritrócitos (22%), se comparado às nanoagulhas (11%), após 48 horas de reação (controle negativo=3,7%). A mesma tendência foi observada para estimulação de neutrófilos avaliada por luminol (nanoflores 26,9%, nanoagulhas 8,9% e controle negativo=8,7%). Em conclusão, podemos afirmar que ZnO nanoestruturado apresentou baixa toxicidade nos modelos aqui estudados, o que reforça a sua potencial aplicação in vivo.
Zinc oxide (ZnO) is a semiconductor that has been highly explored in multiple areas of science, especially in photovoltaic devices and, more recently, in biomedical applications. However, the cytotoxic effects, especially in nanosize, associated with its use cannot be ruled out. Therefore, this work aimed to study how the sonication time can influence the morphology obtained for the zinc oxide and how these differences could affect the structure of albumin, cause hemolysis of erythrocytes and activation of human neutrophils. ZnO was obtained by ultrasonic synthesis method and characterized by optical methods and their morphologies observed in scanning electron microscope. Two differents morphologies were obtained: nanoflowers and nanoneedle. ZnO was incubated with human serum albumin and blood cells (erythrocytes and neutrophils) in final concentration of 0.1mg/ml. The results showed no significant modification in albumin structure when incubated with ZnO, evidenced by intrinsic and extrinsic fluorescence studies. One exception was a small protein aggregation observed in light scattering (Rayleigh). Although somewhat effective, this morphology of ZnO was also more effective at inducing hemolysis of erythrocytes (22%) compared to nanoagulhas (11%), after 48 hours of reaction (negative control = 3.7%). The same trend was observed for stimulation of neutrophils measured by luminol (nanoflowers 26.9% and nanoneedle 8.9%) (negative control = 8.7%). In conclusion, it can be said that ZnO nanostructured showed low toxicity in the models studied, which reinforces the in vivo applications.
Zinc oxide (ZnO) is a semiconductor that has been highly explored in multiple areas of science, especially in photovoltaic devices and, more recently, in biomedical applications. However, the cytotoxic effects, especially in nanosize, associated with its use cannot be ruled out. Therefore, this work aimed to study how the sonication time can influence the morphology obtained for the zinc oxide and how these differences could affect the structure of albumin, cause hemolysis of erythrocytes and activation of human neutrophils. ZnO was obtained by ultrasonic synthesis method and characterized by optical methods and their morphologies observed in scanning electron microscope. Two differents morphologies were obtained: nanoflowers and nanoneedle. ZnO was incubated with human serum albumin and blood cells (erythrocytes and neutrophils) in final concentration of 0.1mg/ml. The results showed no significant modification in albumin structure when incubated with ZnO, evidenced by intrinsic and extrinsic fluorescence studies. One exception was a small protein aggregation observed in light scattering (Rayleigh). Although somewhat effective, this morphology of ZnO was also more effective at inducing hemolysis of erythrocytes (22%) compared to nanoagulhas (11%), after 48 hours of reaction (negative control = 3.7%). The same trend was observed for stimulation of neutrophils measured by luminol (nanoflowers 26.9% and nanoneedle 8.9%) (negative control = 8.7%). In conclusion, it can be said that ZnO nanostructured showed low toxicity in the models studied, which reinforces the in vivo applications.
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Palavras-chave
Óxido de zinco, Nanopartículas, Morfologia, Citotoxicidade