Laboratoire des Interactions Ecotoxicologie, Biodiversité, Ecosystèmes (LIEBE), UMR 7146, CNRS-UPV-M, Université Paul Verlaine-Metz, Metz, France.
Colloids Surf B Biointerfaces. 2012 Apr 1;92:315-21. doi: 10.1016/j.colsurfb.2011.12.012. Epub 2011 Dec 21.
The increasing production and use of titanium dioxide nanoparticles (NP-TiO(2)) has led to concerns about their possible impact on the environment. Bacteria play crucial roles in ecosystem processes and may be subject to the toxicity of these nanoparticles. In this study, we showed that at low ionic strength, the cell viability of Escherichia coli was more severely affected at pH 5.5 than at pH 7.0 and pH 9.5. At pH 5.5, nanoparticles (positively charged) strongly interacted with the bacterial cells (negatively charged) and accumulated on their surfaces. This phenomenon was observed in a much lower degree at pH 7.0 (NP-TiO(2) neutrally charged and cells negatively charged) and pH 9.5 (both NP-TiO(2) and cells negatively charged). It was also shown that the addition of electrolytes (NaCl, CaCl(2), Na(2)SO(4)) resulted in a gradual reduction of the NP-TiO(2) toxicity at pH 5.5 and an increase in this toxicity at pH 9.5, which was closely related to the reduction of the NP-TiO(2) and bacterial cell electrostatic charges.
纳米二氧化钛（NP-TiO(2)）的产量和使用日益增加，这引起了人们对其可能对环境造成影响的担忧。细菌在生态系统过程中起着至关重要的作用，它们可能会受到这些纳米粒子的毒性影响。在这项研究中，我们表明，在低离子强度下，大肠杆菌的细胞存活率在 pH5.5 时比在 pH7.0 和 pH9.5 时受到更严重的影响。在 pH5.5 时，纳米颗粒（带正电荷）与细菌细胞（带负电荷）强烈相互作用，并在其表面上积累。在 pH7.0（NP-TiO(2)带中性电荷，细胞带负电荷）和 pH9.5（NP-TiO(2)和细胞均带负电荷）时，这种现象的观察程度要低得多。研究还表明，添加电解质（NaCl、CaCl(2)、Na(2)SO(4))会导致 NP-TiO(2)在 pH5.5 时的毒性逐渐降低，而在 pH9.5 时毒性增加，这与 NP-TiO(2)和细菌细胞静电电荷的减少密切相关。
