RESUMEN
The application of appropriate analytical techniques is essential for nanomaterial (NM) characterization. In this study, we compared different analytical techniques for NM analysis. Regarding possible adverse health effects, ionic and particulate NM effects have to be taken into account. As NMs behave quite differently in physiological media, special attention was paid to techniques which are able to determine the biosolubility and complexation behavior of NMs. Representative NMs of similar size were selected: aluminum (Al0) and aluminum oxide (Al2O3), to compare the behavior of metal and metal oxides. In addition, titanium dioxide (TiO2) was investigated. Characterization techniques such as dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were evaluated with respect to their suitability for fast characterization of nanoparticle dispersions regarding a particle's hydrodynamic diameter and size distribution. By application of inductively coupled plasma mass spectrometry in the single particle mode (SP-ICP-MS), individual nanoparticles were quantified and characterized regarding their size. SP-ICP-MS measurements were correlated with the information gained using other characterization techniques, i.e. transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The particle surface as an important descriptor of NMs was analyzed by X-ray diffraction (XRD). NM impurities and their co-localization with biomolecules were determined by ion beam microscopy (IBM) and confocal Raman microscopy (CRM). We conclude advantages and disadvantages of the different techniques applied and suggest options for their complementation. Thus, this paper may serve as a practical guide to particle characterization techniques.
RESUMEN
Nicotine is the most important alkaloid compound in tobacco. One of the major effects of nicotine is stimulation of mesocorticolimbic system. Prefrontal cortex plays a pivotal role in personality and mental state. It is considered the main cause of addiction as it is located in mesocorticolimbic dopamine system. Twenty four male rats were divided into four groups based on nicotine administration dose (0, 0.5, 1 and 1.5 g/kg). After animals were anesthetized, their brains were fixed using transcardiac method. Tissue processing and Golgi staining were performed and the stained tissue sections were analyzed by optic microscope and Motic software. By increasing the dose, nicotine significantly decreased the number of neuronal processes. In the higher dose, nicotine caused a significant decrease and increase in the size of pericarions and dendritic spines, respectively (p<0.05). Nicotine administration can decrease the size of pericarion and number of dendritic spines in the prefrontal cortex.
La nicotina es el compuesto alcaloide más importante del tabaco. Uno de sus principales efectos es la estimulación del sistema mesocorticolímbico. La corteza prefrontal desempeña un papel fundamental en la personalidad y estado mental. Esta es considerada la principal causa de la adicción, ya que se encuentra en el sistema mesocorticolímbico dopaminérgico. Veinticuatro ratas macho fueron divididas en cuatro grupos basados en la dosis de administración de nicotina (0, 0,5, 1 y 1,5 g/kg). Luego fueron anestesiados y sus cerebros se fijaron mediante perfusión transcardíaca. Se realizó el procesamiento de tejidos y las secciones bajo tinción de Golgi fueron analizadas mediante microscopia óptica y el software Motic. Con el aumento de dosis, la nicotina redujo significativamente el número de procesos neuronales. En la dosis más alta, la nicotina causó una disminución y aumento significativo en el tamaño de pericarion y espinas dendríticas, respectivamente (p<0,05). La administración de nicotina puede disminuir el tamaño del pericarion y el número de espinas dendríticas en la corteza prefrontal.