Physicochemical factors that affect metal and metal oxide nanoparticle passage across epithelial barriers

Department of Environmental Medicine, University of Rochester, Rochester, NY, USA.
Wiley Interdisciplinary Reviews Nanomedicine and Nanobiotechnology (Impact Factor: 4.49). 07/2009; 1(4):434-50. DOI: 10.1002/wnan.44
Source: PubMed

ABSTRACT The diversity of nanomaterials in terms of size, shape, and surface chemistry poses a challenge to those who are trying to characterize the human health and environmental risks associated with incidental and unintentional exposures. There are numerous products that are already commercially available that contain solid metal and metal oxide nanoparticles, either embedded in a matrix or in solution. Exposure assessments for these products are often incomplete or difficult due to technological challenges associated with detection and quantitation of nanoparticles in gaseous or liquid carriers. The main focus of recent research has been on hazard identification. However, risk is a product of hazard and exposure, and one significant knowledge gap is that of the target organ dose following in vivo exposures. In order to reach target organs, nanoparticles must first breach the protective barriers of the respiratory tract, gastrointestinal tract, or skin. The fate of those nanoparticles that reach physiological barriers is in large part determined by the properties of the particles and the barriers themselves. This article reviews the physiological properties of the lung, gut, and skin epithelia, the physicochemical properties of metal and metal oxide nanoparticles that are likely to affect their ability to breach epithelial barriers, and what is known about their fate following in vivo exposures.

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Available from: Lisa A Delouise, Aug 07, 2014
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    • "Particles less than approximately 15 nm become fully systemic and may enter almost every cell in the body including the brain and bone marrow [5] [6]. However, it is important to note that the majority of metal nanoparticles ingested will likely be excreted in the faeces and some predisposing condition in the gut may be required before any nanoparticles can enter the gut lining cells [5] [6] [7] [8]. The biological impacts from exposure are many which have spawned a new science discipline ''metallomics'' the study of metallic nano-particles in biological systems and their impacts on life [19]. "
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    ABSTRACT: The formation of metallic particulates from erosion was investigated by running a series of transducers at various frequencies in water. Two low frequency transducer sonotrodes were run for 7.5h at 18kHz and 20kHz. Three high frequency plates operating at megasonic frequencies of 0.4MHz, 1MHz, and 2MHz were run over a 7days period. Electrical conductivity and pH of the solution were measured before and after each run. A portion of the non-sonicated and treated water was partially evaporated to achieve an 80-fold concentration of particles and then sieved through nano-filters of 0.1μm, 0.05μm, and 0.01μm. An aliquot of the evaporated liquid was also completely dried on strips of carbon tape to determine the presence of finer particles post sieving. An aliquot was analyzed for detection of 11 trace elements by Inductively Coupled Plasma Mass Spectroscopy (ICPMS). The filters and carbon tapes were analyzed by FE-SEM imaging to track the presence of metals by EDS (Energy Dispersive Spectroscopy) and measure the particle size and approximate composition of individual particles detected. Light microscopy visualization was used to calculate the area occupied by the particles present in each filter and high resolution photography was used for visualization of sonotrode surfaces. The roughness of all transducers before and after sonication was tested through profilometry. No evidence of formation of nano-particles was found at any tested frequency. High amounts of metallic micron-sized particles at 18kHz and 20kHz formed within a day, while after 7day runs only a few metallic micro particles were detected above 0.4MHz. Erosion was corroborated by an increase in roughness in the 20kHz tip after ultrasound. The elemental analysis showed that metal leach occurred but values remained below accepted drinking water limits, even after excessively long exposure to ultrasound. With the proviso that the particles measured here were only characterized in two dimensions and could be nanoparticulate in terms of the third dimension, this research suggests that there are no serious health implications resulting from the formation of nanoparticles under the evaluation conditions. Therefore, high frequency transducer plates can be safely operated in direct contact with foods. However, due to significant production of metallic micro-particulates, redesign of lower frequency sonotrodes and reaction chambers is advised to enable operation in various food processing direct-contact applications.
    Ultrasonics Sonochemistry 04/2014; 21(6). DOI:10.1016/j.ultsonch.2014.04.005 · 4.32 Impact Factor
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    • "There are many factors influencing the nanoparticles penetration to healthy skin. Nanoparticles, shape, superficial charge, composition, hydrodynamic diameter , and physicochemical properties of solvent are expected to affect penetration into skin (Elder et al. 2009). In our study, we used water suspensions of spherically shaped uncharged gold nanoshells and titanium dioxide nanoparticles. "
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    ABSTRACT: A whole cell based biosensor for rapid real-time testing of human and environmental toxicity of nanoscale materials is reported. Recent studies measuring nanoparticle cytotoxicity in vitro provide a final measurement of toxicity to a cell culture overlooking the ongoing cytotoxic effects of the nanoparticles over the desired timeframe. An array biosensor capable of performing multiple cytotoxicity assays simultaneously was designed to address the need for a consistent method to measure real-time assessments of toxicity. The impedimetric response of human lung fibroblasts (CCL-153) and rainbow trout gill epithelial cells (RTgill-W1) when exposed to gold and silver nanoparticles (AuNPs, AgNPs), single walled carbon nanotubes (SWCNTs) and cadmium oxide (CdO) was tested. Exposure to CdO particles exhibited the fastest rate of cytotoxicity and demonstrated the biosensor's ability to monitor toxicity instantaneously in real time. Advantages of the present method include shorter run times, easier usage, and multi-sample analysis leading to a method that can monitor the kinetic effects of nanoparticle toxicity continuously over a desired timeframe.
    Nanotechnology 08/2010; 21(31):315103. DOI:10.1088/0957-4484/21/31/315103 · 3.82 Impact Factor
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