Nanotoxicity: challenges, research gaps, and progress beyond traditional toxicology
2013.2.14
Saber M. Hussain Nanobiotechnology Group Lead Molecular Bioeffects Branch Bioeffects Division Human Effectiveness Directorate Air Force Research Laboratory, Wright Patterson Air Force Base Ohio, USA
February 14th 2013, 11h30, CNC Auditorium (2nd floor, old FMUC building, Pólo I)

Host: Carlos Palmeira


Synopsis:
Previous publications have established a strong foundation for the acute, sizedependent toxicity of silver Nanomaterials (Ag NM), and identify oxidative stress as the mechanism of toxicity in a wide range of cell types. However there is a lack of knowledge, pertaining to realistic exposure doses, appropriate dosimetry, deposition efficiency, and long‐term cellular consequences, based on nanomaterials (NM) physical parameters. To address these research gaps, we have developed a NM quick‐screen procedure, using a multi‐cell model approach, as well as low level acute and chronic NM studies to elucidate the subsequent impact on cell signaling and gene expression. Our acute, low‐level Ag NM studies demonstrated that in the absence toxicity, the cells had significant alterations in cell signaling, gene expression, and inflammation; signifying an acute stress response. Furthermore, in these acute, low‐level studies; the size, shape, and coating of the NM contributed to the observed cellular responses. In comparison, the low‐level Ag NM chronic studies demonstrated increased activation of a p38 stress mediated pathway, which led to actin disorganization, increased cellular repair and heightened EGF signaling. The differences were significant in the observed response between acutely‐dosed and chronically‐dosed cells, indicating that studies evaluating the length of exposure to NMs are imperative. Taken together, these studies indicate the need to progress beyond traditional toxicity evaluations to fully understand the implications of NM exposure, with emphasis on the physical and chemical behavior of particles in a cell environment.
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