Ways to look at skin for nano particles. Also mucosa, lungs, liver, spleen, etc.
Ways of screening.
But, to start off
carbon nanotubes ARE causing problems.:
.........Single-Walled Carbon Nanotube (SWCNT)-induced interstitial fibrosis in the lungs of rats is associated with increased levels of PDGF mRNA and the formation of unique intercellular carbon structures that bridge alveolar macrophages In Situ.......
www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17134509THERE IS CONCERN OVER NANO PARTICLES
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Principles for characterizing the potential human health effects from exposure to nanomaterials: elements of a screening strategy............ 4.2.2.2 Skin. Skin or the integument is the largest organ of the body and is unique because it is a potential route for exposure to nanoparticles during their manufacture and also provides an environment within the avascular epidermis where particles could potentially lodge and not be susceptible to removal by phagocytosis [110]. What are the toxicological consequences of "dirty" nanoparticles (catalyst residue) becoming lodged in the epidermis? In fact, it is this relative biological isolation in the lipid domains of the epidermis that has allowed for the delivery of drugs to the skin using lipid nanoparticles and liposomes. Larger particles of zinc and titanium oxide used in topical skin-care products have been shown to be able to penetrate the stratum corneum barrier of rabbit skin with highest absorption occurring from water and oily vehicles [111]. This could also apply to manufactured nanoparticles. Can nanoparticles gain access to the epidermis after topical exposure, the first step in a toxicological reaction? Exposure to metallic nanoparticles, whose physical properties would allow them to catalyze a number of biomolecular interactions, potentially could produce adverse toxicological effects. More information is required regarding the efficiency of decontamination of nanoparticles from skin since solubilization and dilution, the two hallmarks of post-exposure decontamination, might be less efficacious for these solid structures.
Research should address the effects of dermal and systemic exposure to a number of types of nanoparticles in the skin. The skin is a primary route of potential exposure to toxicants, including novel nanoparticles. However, there is no information on whether particles are absorbed across the stratum corneum barrier or whether systemically administered particles can accumulate in dermal tissue. Nanoparticles may traverse through the stratum corneum layers at varying rates due to particle size or become sequestered within the epidermis to increase their exposure time to viable epidermal keratinocytes.
Nanomaterials are difficult to obtain in large quantities; therefore, it is best to conduct in vitro tests to estimate in vivo starting doses for toxicity testing [112]. At least three or four concentrations with controls should be used in all in vitro systems. These data would provide a preliminary, but relevant, assessment of both systemic exposure after topical administration as well as cutaneous hazard after both topical and systemic exposure, two essential components of any risk assessment.
Cell Culture. Human epidermal keratinocyte (HEK) monolayers can be affected by nanoparticle interactions. It has already been shown that changes in biomarkers of viability and toxicity can occur with exposure to multi-wall carbon nanotubes [50]. Cytotoxicity endpoints should be evaluated: 1) cell viability-metabolic markers such as mitochondrial reduction of tetrazolium salts into insoluble dye (MTT), 2) decreased cell viability-membrane markers like neutral red uptake into cell lysosomes, trypan blue exclusion and cell attachment/cell detachment, and 3) pro-inflammatory cytokine affects measured by TNFá, IL-8, IL-6, IL-10, or IL-1â. Genomics and proteomics assays could be used to explore the mechanism behind the toxicity. However, caution must be taken when using carbon black or any other material as a control because complications may occur. Carbon can adsorb the viability dyes, such as neutral red, and interfere with the absorption spectra. False positives will occur. The type of carbon black used is extremely important. For instance, ultrafine carbon black has been utilized in inhalation studies but dosing in cell culture gives different results, especially when conducting viability and cytokine assays.
Three dimensional skin cell cultures are also available commercially. They have shown to be able to predict irritation but may significantly overestimate absorption or penetration [113-116]. Assays listed above can be used but may not be applicable with nanomaterials due to adsorption.
Flow-through Diffusion Cell Studies. Diffusion cell system consists of flow-through diffusion blocks each containing multiple Teflon cells perfused by a constant temperature circulator through a Silastic oxygenator, an automatic fraction collector, and a desiccant. Circular fresh skin from pigs (pig skin mimics human skin and eliminates the extreme variability seen with random source human skin) or humans are placed epidermal – side up in Teflon flow-through diffusion cell. Compound containing nanoparticles is dosed on the epidermal side whilst the dermal side in each cell is bathed with receptor fluid at a set flow rate. The perfusate is collected at defined intervals up to 24 hrs and nanoparticles flux in the perfusate can be assessed by radioactivity counting, fluorescence, or UV detection. The skin surface can then be swabbed to remove non-absorbed surface particles and then tape stripped to remove a stratum corneum sample to assess nanoparticle penetration into this outermost epidermal layer. Serial sectioning of the skin can also be carried out [117,118].
Isolated Perfused Porcine Skin Flap (IPPSF). The isolated perfused porcine skin flap (IPPSF) would be an ideal model to study the absorption and toxicity of nanomaterials. The IPPSF has an intact functional microcirculation, a viable epidermis and dermis and can be well controlled. A single-pedicle, axial pattern tubed skin flap is obtained from the abdomen of pigs following surgical creation of the flap perfused primarily by the caudal superficial epigastric artery and its associated paired venae commitantes. The IPPSF is transferred to the perfusion apparatus that is a custom designed temperature and humidity-regulated chamber. Nanomaterials can be topically dosed to the skin surface and perfusate samples collected over an eight hour period and assessed for nanoparticle flux [119-121].
Other acute toxicity in vitro assays are available but are used to test corrosives (rat transcutaneous electrical resistance (TER), commercially available EPISKIN, Epiderm and Corrositex) and irritation (EPISKIN, and Epiderm). However, the major traditional endpoint for skin toxicity is using the cell viability assay MTT reduction that has been shown to be unpredictable with nanomaterials due to marker interactions with nanoparticles.".......
more on liver, kidney, brain barrier, lungs, blood, intestinal etc. SO THERE IS CONCERN OVER THESE NANO PARTICLES. Just as there has been for the SWNT Bucky balls.
www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=16209704 A lot of information in those links WhiteRose, thank you for the specific areas.
I will concentrate on skin for now, since seems way in besides the gut. There is some info on the Principles page from link about the GI tract.
But, if there is to be screening, why can't we be screened for these now? What are we waiting for? Where and why are the medical folks not screening us for these. They know there is potential danger there. Or are they waiting till after the fact, after, many have died, then they will do autopsies? MY LEFT FOOT!
THIS REPORT AND CALL FOR USE OF PRINCIPLES WAS IN 2005 AND THEY DO NOT HAVE THESE SCREENING TESTS AVAILABLE? BS......
Skytroll