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The objective of this study was to evaluate the effects of AgNPs on Artemia salina and Allium cepa, evaluating the influence of the dilution solutions on the particle behavior. The AgNPs were synthesized by chemical reduction of AgNO3 (3 and 5 mmol L−1) with sodium borohydride and stabilized with PVA (polyvinyl alcohol) and CMC (sodium carboxymethyl cellulose). The toxicity of AgNPs was evaluated in Artemia salina (mortality) using Meyer’s solution as a diluent and in Allium cepa (chromosomal aberrations) using reconstituted hard water. AgNPs showed characteristic molecular absorption bands. Particles with CMC presented hydrodynamic radius between 4 and 102 nm and with PVA between 7 and 46 nm. The studied dispersions were toxic to A. salina species. Meyer’s solution, used as dilution water in the test, caused precipitation of Ag+ and also caused changes in CMC-stabilized AgNPs, changing the shape of the nanoparticles by depositing precipitates on their surface. These changes make the results of toxicity difficult to interpret. AgNPs stabilized with PVA remained unchanged. AgNPs affected cell division and caused the appearance of chromosomal aberrations on A. cepa. Higher numbers of chromosomal aberrations occurred in dispersions with smaller particle diameters (AgNPs3-PVA and AgNPs5-PVA, without dilution). In the studied conditions the dispersions were toxic to the tested organisms, the concentrations of precursors and the type of stabilizer used influenced the particle size and toxicity. In the test with A. cepa, the reconstituted hard water did not cause changes in the dispersions of AgNPs, whereas for A. salina the Meyer solution promoted aggregation of the particles and precipitation, in the dispersions stabilized with CMC, thus changing the samples.

RESUMO A nanotecnologia e uma area do conhecimento que comecou a ser explorada neste seculo e apresenta receptividade em varios segmentos industriais devido as propriedades distintas das nanoparticulas e melhorias que elas proporcionam a materiais. Apesar disso, algo pouco explorado sao as propriedades nocivas que estas podem exercer sobre os seres vivos. Por exemplo, as nanoparticulas de prata (nAg) apresentam propriedades bactericidas e vem sendo utilizadas para aplicacao em roupas, cateteres, recheios de filtros e etc. Este trabalho teve como objetivo a sintese e a caracterizacao de nAg obtidas por diferentes rotas sinteticas estabelecidas pela literatura. As nAgs obtidas foram caracterizadas atraves da espectroscopia de absorcao no UV-vis e pela tecnica de espalhamento de luz dinâmico (DLS). As particulas obtidas nas reacoes A, B, C e D apresentaram diâmetro medio entre 10 a 14 nm uma vez que todas absorvem nos comprimentos de onda entre 395 a 405nm. O tamanho real medio das particulas das reacoes B e E, obtido atraves do metodo DLS, foi de 10,82 nm para a reacao B e 2,58 nm para a reacao E.