title: Chitosan nanoparticles loaded the herbicide paraquat: the influence of the aquatic humic substances on the colloidal stability and toxicity.
abstract: Polymeric nanoparticles have been developed for several applications, among them as carrier system of pesticides. However, few studies have investigated the fate of these materials in the environment in relation to colloidal stability and toxicity. In nature, humic substances are the main agents responsible for complexation with metals and organic compounds, as well as responsible for the dynamics of these nanoparticles in aquatic and terrestrial environments. In this context, the evaluation of the influence of aquatic humic substances (AHS) on the colloidal stability and toxicity of polymeric nanoparticles of chitosan/tripolyphosphate with or without paraquat was performed. In this study, the nanoparticles were prepared by the ionic gelation method and characterized by size distribution measurements (DLS and NTA), zeta potential, infrared and fluorescence spectroscopy. Allium cepa genotoxicity studies and ecotoxicity assays with the alga Pseudokirchneriella subcapitata were used to investigate the effect of aquatic humic substances (AHS) on the toxicity of this delivery system. No changes were observed in the physical-chemical stability of the nanoparticles due to the presence of AHS using DLS and NTA techniques. However some evidence of interaction between the nanoparticles and AHS was observed by infrared and fluorescence spectroscopies. The ecotoxicity and genotoxicity assays showed that humic substances can decrease the toxic effects of nanoparticles containing paraquat. These results are interesting because they are important for understanding the interaction of these nanostructured carrier systems with species present in aquatic ecosystems such as humic substances, and in this way, opening new perspectives for studies on the dynamics of these carrier systems in the ecosystem.
authors: Department of Environmental Engineering, UNESP - Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil; Department of Biochemistry, Institute of Biology, UNICAMP, Cidade Universitária Zeferino Vaz s/n, Campinas, SP, Brazil.
authors: Renato
authors: R
authors: Grillo
authors: Department of Environmental Engineering, UNESP - Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil; Embrapa Environmental, Jaguariúna, SP, Brazil.
authors: Zaira
authors: Z
authors: Clemente
authors: Department of Environmental Engineering, UNESP - Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil.
authors: Jhones Luis
authors: JL
authors: de Oliveira
authors: Department of Environmental Engineering, UNESP - Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil; Department of Biochemistry, Institute of Biology, UNICAMP, Cidade Universitária Zeferino Vaz s/n, Campinas, SP, Brazil.
authors: Estefânia Vangelie Ramos
authors: EV
authors: Campos
authors: Embrapa Environmental, Jaguariúna, SP, Brazil.
authors: Victor C
authors: VC
authors: Chalupe
authors: Embrapa Environmental, Jaguariúna, SP, Brazil.
authors: Claudio M
authors: CM
authors: Jonsson
authors: Department of Biotechnology, University of Sorocaba, Sorocaba, SP, Brazil.
authors: Renata
authors: R
authors: de Lima
authors: Department of Biotechnology, University of Sorocaba, Sorocaba, SP, Brazil.
authors: Gabriela
authors: G
authors: Sanches
authors: Department of Biotechnology, University of Sorocaba, Sorocaba, SP, Brazil.
authors: Caroline S
authors: CS
authors: Nishisaka
authors: Department of Environmental Engineering, UNESP - Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil.
authors: André H
authors: AH
authors: Rosa
authors: Department of Food Technology and Bioprocess Engineering, Max Rubner-Institut, Karlsruhe, Germany.
authors: Kathleen
authors: K
authors: Oehlke
authors: Department of Food Technology and Bioprocess Engineering, Max Rubner-Institut, Karlsruhe, Germany.
authors: Ralf
authors: R
authors: Greiner
authors: Department of Environmental Engineering, UNESP - Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil; Department of Biochemistry, Institute of Biology, UNICAMP, Cidade Universitária Zeferino Vaz s/n, Campinas, SP, Brazil. Electronic address: leonardo@sorocaba.unesp.br.
authors: Leonardo F
authors: LF
authors: Fraceto
mesh_terms: D048271:Chitosan / Q000633:toxicity*; D000460:Chlorophyta / Q000187:drug effects / Q000254:growth & development; D003102:Colloids; D006540:Herbicides / Q000633:toxicity*; D006812:Humic Substances; D053758:Nanoparticles / Q000633:toxicity*; D019697:Onions / Q000187:drug effects / Q000235:genetics; D010269:Paraquat / Q000633:toxicity*; D011122:Polyphosphates / Q000633:toxicity*
chemical_list: D003102:Colloids; D006540:Herbicides; D006812:Humic Substances; D011122:Polyphosphates; D048271:Chitosan; C005692:triphosphoric acid; D010269:Paraquat
keywords: Herbicides; Natural organic matter; Paraquat; Polymeric nanoparticles; Toxicity