Tuesday, March 6, 2007

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delicate side of novelty and mobility of the nano.
The unique properties of nanoscale materials have hope to have effective medical treatments and better diagnosis, including more accurate imaging. Because of its tiny size, nanomaterials may have easy access to areas of the body that are outside the scope of current therapies. Quantum effects showing some nano-optical, electrical or structural rare that only show at the nanometer scale, can increase the functionality of the materials available. The irony is that the qualities that make nanomaterials so attractive to researchers and industry in a wide range of fields-their smallness, their mobility and their unusual properties, "could be the same qualities that could be harmful to human health.
Virtually all scientists agree that the toxicology of nano-engineered materials is largely unknown, and that toxicity data can not be extrapolated from existing toxicology studies were made in scale particles mayores.41 In other words, it is likely that the toxicity of a substance formed by particles of one micron in diameter differs from the toxicity of particles (the same substance) with only 10 nm in diameter (one micron is equivalent to a thousand nm) . This is because the smaller a particle, higher the percentage of atoms that are on the surface. A large surface area corresponds to a high level of reactivity
-and, in general, the more reactive a substance is more toxic it is. However, it is generally true may not remain in the nanometer scale. The behavior of the materials in this range (between ~ 1-100 nm) is unpredictable, and scientists of late suggest that the shape and surface structure of nanoscale materials are also important factors in determining their reactivity and toxicity, making nanoscopic field of toxicology even more crucial.42

This knowledge gap requires urgent attention because there are hundreds of products containing nano-materials and are already on the market, 43 and there is no federal agency in the world to regulate nanomaterials as such. The increased bioavailability associated with nanoscale materials, means that the nano-formulated drug doses should be monitored more carefully, as "pack more energy" than their counterparts in larger scale, an overdose could pose serious problemas.En the same sense, their greater mobility could be a disadvantage.

access to the brain is especially useful when treat brain cancers, but on the other hand, we should not allow free rein in our bodies all designed nano-particles to which we are exposed through the environment, or through commercial nanoscale products. A recent study suggests that the increase in reactivity shown by the nano-particles of titanium dioxide (TiO2), which are often used as an ingredient in sunscreens, can cause damage to the brain microglia cells whose purpose is to protect the nervous system central.44 Despite the fact that sunscreens and cosmetics designed nano-particles containing commercial, including TiO2 there is no scientific consensus on how much they can penetrate the skin of nano-particles. Even nanoscale materials designed to come into our bodies as drug targeting or imaging agents can create problems if they miss their target and lodge in our cells, brain or other organs.
In advising nanotechnology innovations for the health sector, Frost & Sullivan, an international market research, says, "The nano-particles and nano-materials used in applications related to drug discovery can become a source of concern if you break down too soon or if they remain in the body for prolonged periods. The ability of nanomaterials to interact with biological organisms raises the possibility that they are harmful to humans or the environment ... The current understanding of the potential toxicity of nanoparticles is limited, but research indicates that some of these products may enter the human body and become toxic at the cellular level in various fluids, tissues and / or body organs.

"Particles without borders? Can reach the central nervous system nanoparticles inhale? Can penetrate through layers of the skin of nano-particles of sunscreens and cosmetics? "Cross-brain barrier? How small must be to enter cells? It is unclear how much they can translocate (move side to side) nanoscale particles in the body. It seems that the size, composition and shape of a particle plays a role in this. A recent study showed that spherical particles, some with a diameter of 14 nm and others with 74 nm in diameter, penetrate cells more easily than nanoscale particles into bars measuring 14 x 74 nm.46 spherical particles 50 nm however, are twice as likely to enter the spherical particles slightly higher or slightly menores.47 A study in rats shows that inhaled nanoparticles smaller than 40 nm can reach the brain (specifically the olfactory bulb) via the nerve olfativo.48 This finding is potentially significant for the development of drug delivery methods and nanotoxicology because it suggests that nanoscale particles may be able to circumvent the very tight blood-brain barrier.
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