RESUMO
There is increasing concern over the risks of nanoparticles to humans and the environment, but little is known about the properties of the nanoparticulate mineral filters, such as titanium dioxide and zinc oxide, in sunscreens. There is an urgent need to develop methods for characterizing nanoparticles in (NPs) such products to provide data for human and environmental risk assessments. This study explored three methods (transmission electron microscopy [TEM], conventional scanning electron microscopy [SEM], and wet-scanning electron microscopy [WetSEM]) for characterizing NPs in sunscreens. Our results showed that these products contained titanium dioxide and zinc oxide particles in the nanometer range; thus, it is likely that consumers and the environment are exposed to engineered NPs through the use of these products. Further, we found that the combination of all three microscopy methods provided the most comprehensive information on size-related properties, which are crucial parameters for risk assessment of NPs in wet matrices.
Assuntos
Nanopartículas Metálicas/química , Protetores Solares/química , Titânio/química , Óxido de Zinco/química , Microscopia Eletrônica , Tamanho da Partícula , ÁguaAssuntos
Anticoagulantes/uso terapêutico , Fator Xa/efeitos dos fármacos , Hematologia/tendências , Inibidores da Agregação Plaquetária/uso terapêutico , Fibrinolíticos/uso terapêutico , Fondaparinux , Doenças Hematológicas/sangue , Doenças Hematológicas/tratamento farmacológico , Humanos , Contagem de Plaquetas , Polissacarídeos/uso terapêuticoAssuntos
Antineoplásicos/uso terapêutico , Neoplasias Hematológicas/tratamento farmacológico , Hematologia/tendências , Animais , Antineoplásicos Alquilantes/uso terapêutico , Ensaios Clínicos Fase I como Assunto , Dacarbazina/análogos & derivados , Dacarbazina/uso terapêutico , Humanos , Hidrazinas/uso terapêutico , Leucemia Mieloide/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-kit/efeitos dos fármacos , Sulfonamidas/uso terapêutico , TemozolomidaAssuntos
Biotecnologia/tendências , Indústria Farmacêutica/tendências , Animais , Antineoplásicos/uso terapêutico , Biotecnologia/economia , Vacinas Anticâncer/uso terapêutico , China , Ensaios Clínicos como Assunto , Desenho de Fármacos , Indústria Farmacêutica/economia , Medicamentos de Ervas Chinesas/economia , Terapia Genética/economia , Terapia Genética/tendências , Humanos , Imunoterapia/economia , Imunoterapia/tendências , Itália , Medicina Tradicional Chinesa/economia , Medicina Tradicional Chinesa/tendências , Apoio à Pesquisa como Assunto , Vacinas contra Hepatite Viral/economiaAssuntos
Ansiolíticos/uso terapêutico , Antidepressivos/uso terapêutico , Agressão/efeitos dos fármacos , Animais , Ansiolíticos/farmacologia , Antidepressivos/farmacologia , Humanos , Hiperalgesia/tratamento farmacológico , Indóis/uso terapêutico , Pirrolidinas/uso terapêutico , Receptores Opioides delta/agonistas , Tiazóis/uso terapêuticoAssuntos
Analgésicos/uso terapêutico , Doenças Neurodegenerativas/tratamento farmacológico , Dor/tratamento farmacológico , Animais , Caprilatos/uso terapêutico , Transtornos Cognitivos/tratamento farmacológico , Ácido Egtázico/análogos & derivados , Ácido Egtázico/uso terapêutico , Humanos , Doença de Parkinson/tratamento farmacológico , Canais de Cátion TRPV/antagonistas & inibidoresAssuntos
Agonistas de Dopamina/farmacologia , Agonistas de Receptores de GABA-A , Imidazóis/farmacologia , Piperidinas/farmacologia , Receptores de Dopamina D4/agonistas , Agonistas do Receptor 5-HT4 de Serotonina , Agonistas do Receptor de Serotonina/farmacologia , Sulfonamidas/farmacologia , Animais , Humanos , Neurotransmissores/metabolismoAssuntos
Esclerose Lateral Amiotrófica/tratamento farmacológico , Epilepsia/tratamento farmacológico , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Esclerose Múltipla/tratamento farmacológico , Óxido Nítrico Sintase/antagonistas & inibidores , Receptores Opioides delta/agonistasRESUMO
The increasing industrial production of engineered nanoparticles (ENPs) raises concern over their safety to humans and the environment. There is a lack of knowledge regarding the environmental fate and impact of ENPs and in situ methods are needed to investigate e.g. nanoparticle aggregation and adsorption in the media of concern such as water, sediment and soil. In this study, the application of wet scanning electron microscopy (WetSEM) technology in combination with energy dispersive x-ray spectroscopy (EDS) to visualise and elementally identify metal and metal oxide nanoparticles (Au, TiO(2), ZnO and Fe(2)O(3)) under fully liquid conditions in distilled and lake water as well as in a soil suspension has been investigated. WetSEM capsules comprise an electron transparent membrane enabling the imaging and EDS analysis of liquid samples. Results are compared with conventional SEM images and show that WetSEM/EDS is a promising complementary tool for the in situ investigation of ENPs and their aggregates in natural matrices. In combination with other analytical tools (e.g. HDC- or FFF-ICP-MS, DLS), WetSEM could help to provide a better understanding of the fate and behaviour of ENPs in the environment.
Assuntos
Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Poluentes Químicos da Água/química , Meio Ambiente , Compostos Férricos/química , Água Doce/química , Ouro/química , Cinética , Nanopartículas Metálicas/química , Nanotecnologia , Titânio/química , Óxido de Zinco/químicaRESUMO
Nanotechnology is developing rapidly and, in the future, it is expected that increasingly more products will contain some sort of nanomaterial. However, to date, little is known about the occurrence, fate and toxicity of nanoparticles. The limitations in our knowledge are partly due to the lack of methodology for the detection and characterisation of engineered nanoparticles in complex matrices, i.e. water, soil or food. This review provides an overview of the characteristics of nanoparticles that could affect their behaviour and toxicity, as well as techniques available for their determination. Important properties include size, shape, surface properties, aggregation state, solubility, structure and chemical composition. Methods have been developed for natural or engineered nanomaterials in simple matrices, which could be optimized to provide the necessary information, including microscopy, chromatography, spectroscopy, centrifugation, as well as filtration and related techniques. A combination of these is often required. A number of challenges will arise when analysing environmental and food materials, including extraction challenges, the presence of analytical artifacts caused by sample preparation, problems of distinction between natural and engineered nanoparticles and lack of reference materials. Future work should focus on addressing these challenges.
Assuntos
Exposição Ambiental/análise , Monitoramento Ambiental/métodos , Contaminação de Alimentos/análise , Nanopartículas/análise , Animais , Humanos , Nanopartículas/toxicidade , Medição de RiscoRESUMO
Experimental low-loss electron (LLE) yields were measured as a function of loss energy for a range of elemental standards using a high-vacuum scanning electron microscope operating at 5 keV primary beam energy with losses from 0 to 1 keV. The resulting LLE yield curves were compared with Monte Carlo simulations of the LLE yield in the particular beam/sample/detector geometry employed in the experiment to investigate the possibility of modeling the LLE yield for a series of elements. Monte Carlo simulations were performed using both the Joy and Luo [Joy, D.C. & Luo, S., Scanning 11(4), 176988 (2005)] to assess the influence of the more recent stopping power data on the simulation results. Further simulations have been conducted to explore the influence of sample/detector geometry on the LLE signal in the case of layered samples consisting of a thin C overlayer on an elemental substrate. Experimental LLE data were collected from a range of elemental samples coated with a thin C overlayer, and comparisons with Monte Carlo simulations were used to establish the overlayer thickness.