Nanomaterials: A challenge for toxicologists

Dhawan, Alok; Sharma, Vyom; Parmar, Devendra

doi:10.1080/17435390802578595

Cited by 128 publications

(62 citation statements)

References 35 publications

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“…One related question is whether nanoparticles are more toxic than their larger counterparts [2,3]. Hsiao and Huang [4], for example, were able to demonstrate that the cytotoxicity of ZnO is size-dependent.…”

Section: Introductionmentioning

confidence: 99%

“…The link between protein corona and ZnO, particularly in view of its solubility should be further investigated. All in all, comprehensive characterization of the materials used is necessary for interpretation of toxicological results, as mentioned in numerous reviews [3,[20][21][22]. Especially the behavior of nanoparticles under physiological conditions must be considered to fully understand the interactions with components of the culture media [20].…”

Section: Introductionmentioning

confidence: 99%

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Implications of the stability behavior of zinc oxide nanoparticles for toxicological studies

2014

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The increasing use of zinc oxide (ZnO) nanoparticles in sunscreens and other cosmetic products demands a risk assessment that has to be done in toxicological studies. Such investigations require profound knowledge of the behavior of ZnO in cell culture media. The current study was performed to get well-dispersed suspensions of a hydrophilic (ZnO-hydro) and a lipophilic coated (ZnO-lipo) ZnO nanomaterial for use in in vitro tests. Therefore, systematic tests were carried out with common dispersants (phosphate, lecithin, proteins) to elucidate chemical and physical changes of ZnO nanoparticles in water and physiological solutions (PBS, DMEM). Nonphysiological stock suspensions were prepared using ultrasonication. Time-dependent changes of pH, conductivity, zeta potential, particle size and dissolution were recorded. Secondly, the stock suspensions were added to physiological media with or without albumin (BSA) or serum (FBS), to examine characteristics such as agglomeration and dissolution. Stable stock suspensions were obtained using phosphate as natural and physiological electrostatic stabilizing agent. Lecithin proved to be an effective wetting agent for ZnO-lipo. Although the particle size remained constant, the suspension changed over time. The pH increased as a result of ZnO dissolution and formation of zinc phosphate complexes. The behavior of ZnO in physiological media was found to depend strongly on the additives used. Applying only phosphate as additive, ZnOhydro agglomerated within minutes. In the presence of lecithin or BSA/serum, agglomeration was inhibited. ZnO dissolution was higher under physiological conditions than in the stock suspension. Serum especially promoted this process. Using body-related dispersants (phosphate, lecithin) non-agglomerating stock suspensions of hydrophilic and lipophilic ZnO were prepared as a prerequisite to perform meaningful toxicological investigation. Both nanomaterials showed a non-negligible dissolution behavior that strongly depended on the surrounding conditions. Agglomeration of ZnO particles in physiological media is a complex function of particle coating, used dispersants and serum proteins if supplemented. The present study gives a clear guideline how to prepare and handle suspensions with ZnO for in vitro testing and allows the correlation between the chemical-physical particles behavior with findings from toxicological tests.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Implications of the stability behavior of zinc oxide nanoparticles for toxicological studies

2014

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“…The concern about the impact of nanoparticles (NPs) in the environment has increased because their release and accumulation are inevitable [2]. NMs may constitute a toxicological risk as nanosized particles have presented toxicity in a variety of organisms, being generally more toxic than larger particles (bulk) [3]. In fact, NPs behave differently from bulk materials, with regard to chemical, physical and biological properties, due to a change in the nature of the interaction forces between NPs and environment.…”

Section: Introductionmentioning

confidence: 99%

Quenching of chlorophyll fluorescence induced by silver nanoparticles

Queiroz

Mezacasa

Graciano

et al. 2016

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…86 Neste sentido, novos indicadores vêm sendo propostos como parâmetro de efeito tóxico, entre eles o número de NTCs presentes no meio de exposição e não sua massa. 106,107 Já a área de superfície tem sido apontada como uma alternativa melhor para se entender a resposta celular de exposição aos NTCs, já que estaria correlacionada com a indução de estresse oxidativo no interior da célula. 4,103,106,108 Outra questão que merece atenção se relaciona ao fato de que a maioria dos trabalhos tem utilizado doses que não necessariamente refletem a realidade de exposição aos nanomateriais.…”

Section: Dosimetria Na Nanotoxicologia De Nanotubos De Carbonounclassified

Citotoxicidade e genotoxicidade de nanotubos de carbon

Franchi¹,

Santos²,

Matsubara³

et al. 2012

Quím. Nova

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Recebido em 2/5/11; aceito em 6/9/11; publicado na web em 8/11/11 CYTOTOXICITY AND GENOTOXICITY OF CARBON NANOTUBES. There are many controversies regarding the cyto-and genotoxicity of carbon nanotubes (CNTs). In this work, we discuss that many of the incongruous arguments are probably associated with the poor physical-chemical characterization of the CNT samples used in many publications. This manuscript presents examples of carbon nanostructures observed under high resolution electron microscopy that can be found in typical CNT samples, and shows which roles in cyto-and genotoxicity need to be better investigated. Issues concerning chemical treatment are addressed and examples of misunderstandings that can occur during the studies of cyto-and genotoxicity of CNT samples are given.Keywords: cell viability; DNA damage; carbon nanotube samples. INTRODUÇÃOA ideia de nanotecnologia como uma ciência de manipulação molecular ou de escala nanométrica sempre foi um fascínio para muitos pesquisadores. Feynman em 1959 e Drexler em 1986 já chamavam a atenção da comunidade científica com relação à nanotecnologia. 1,2 Com os avanços da microscopia e de outras técnicas, a nanotecnologia se tornou nos últimos 10 anos uma das áreas mais importantes da ciência e da inovação tecnológica com projeções comerciais estimadas para 2015 em um trilhão de dólares. 3,4 Nesse contexto a Nanotoxicologia desempenha um papel importante, pois investiga os efeitos dos nanodispositivos e nanoestruturas em sistemas biológicos. 5 A avaliação toxicológica de partículas e fibras em escala nanométrica 6 contribui para uma série de questões ligadas à utilização de nanomateriais em produtos comerciais. Sendo assim, o entendimento dos mecanismos de cito-e genotoxicidade de um dado nanomaterial é fundamental para a definição de seu impacto ambiental e de estratégias de proteção aos trabalhadores e consumidores. 7 O presente artigo apresenta uma revisão de estudos realizados sobre a eventual indução de danos às células e ao DNA (citotoxicidade e genotoxicidade, respectivamente) por nanotubos de carbono (NTCs), conduzidos em experimentos in vitro. Na literatura existente é possível detectar várias controvérsias e questões que ainda precisam ser esclarecidas já que algumas dessas nanoestruturas se apresentam biocompatíveis. Recentes estudos demonstraram, por exemplo, que a enzima mieloperoxidase presente em neutrófilos humanos é capaz de degradar nanotubos de carbono de parede simples (NTCPS) e que os produtos da biodegradação dos NTCs não induziram inflamação quando expostos aos pulmões de camundongo. [8][9][10][11][12] Embora haja um conflito sobre o mérito do descobrimento dos NTCs, 13 o fato é que esses são um dos nanomateriais mais fascinantes e estudados nas últimas duas décadas. Um NTCPS pode ser descrito basicamente como uma folha de grafeno enrolada e fechada em cada extremidade por metade de um fulereno. Quando várias folhas de grafeno constituem a parede do tubo os mesmos são classificados como NTCs de parede múltiplas (NTCPM). 14 Os NTCs aprese...

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Nanomaterials: A challenge for toxicologists

Cited by 128 publications

References 35 publications

Implications of the stability behavior of zinc oxide nanoparticles for toxicological studies

Implications of the stability behavior of zinc oxide nanoparticles for toxicological studies

Quenching of chlorophyll fluorescence induced by silver nanoparticles

Citotoxicidade e genotoxicidade de nanotubos de carbon

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