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kathy tran

on 6 June 2013

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By: Kathy Tran VCE Nicholas. Nanotechnology assignment PHYSICAL PROPERTIES OF NANOPARTICALS. Another property of titanium dioxide is that it reflects all colors in the visible light spectrum, therefore the light reflected from titanium dioxide is white. This characteristic makes it useful as a white pigment in paints and may make for white residue on your skin when you slather on sunscreen.

The study based on titanium dioxide nanoparticles allow researchers and scientists to form photocatalysts that are more effective because they have more surface area available to react with other molecules. Also, in the nanoparticle form, titanium dioxide can be used in creams and coatings that absorb UV without causing a white coating because of their smaller structures. There smaller shape also indicates that instead of UV lights been absorped it gets reflected off the surface of the particals.

Nanoparticles of a material show different properties compared to larger particles of the same material. Forces of attraction between surfaces can appear to be weak on a larger scale, but on a nanoscale they are considered strong.One reason for this is because nano particals has a higher surface are than volume ration which helps it reflect light. NANO TECHNOLOGY USAGE SUNSCREEN. The use and control of matter on a miniature or microscopical level is called nanotechnology. This tiny matter is referred to as nanoparticles.
These particles are measured in a unit called nanometres (nm). A nanometre is one billionth of a metre (0.000 000 001m). Nanotechnology involves process where scientist will manipulate nanoparticles of mater to test it's response to stimulus such as sunlight, this is because even though a known element has a set of properties, the nanoparticles of that property will not act the same due to their size. Nanotechnology is used widely in a range of products on the market and is expected to play an increasingly significant role in the future. Nanotechnology offers a number of potentially important benefits in health care. Nanotechnology is used in some sunscreen products that contains zinc oxide and titanium dioxide. These two chemicals are particularly valuable in sunscreens because they give broad protection from damaging sunlight. In conventional applications zinc oxide and titanium dioxide leave a white layer on the skin, but when they are reduced to nanoparticles this white layer does not appear while still actively provide the same level of protection from the sun. ARE NANOPRACTICALS SAFE TO USE IN SUNSCREEN? To date, the assements upon the usuage of nanoparticals in sunscreen does ot pose a risk to the overall human health. The active ingredients in sunscreens includes Titanium dioxide and zinc oxide. These particles acts to reflect or absorb UV rays dependent upon their sizes. The concerns the general public tend to have over the usuage of nano particals in suncreens is the fear that they generate free radicals which could potentially pentrate cells and interact eith cell protein or DNA in an unknown way. However, the lack of proof in the health damages of nanotech in sunscreens is very low.

One of the main concerns which is often mentioned about nanotechnology is that of 'grey goo' formed from nanomachines or nanobots which are capable of making copies of themselves. Nano-particles and Sunscreen Skin cancer, including melanoma and non-melanoma, is Australia's most common cancer. Nanotechnology has been used in sunscreens for many years. Nanotechnology is the engineering of functional systems on a molecular scale. This covers both current work and concepts that are more advanced.
In its original sense, 'nanotechnology' refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products. In this case, Sunscreen is a product made of nano-particals that aid in defense to harmful UV rays. Sunscreen protection against UV rays Sunscreens are used to protect the skin against the harmful effects of UV lights (ultra violet rays) emitted by the sun. Although the vast majority of these rays are blocked by the ozone layer a majority is still able to reach the surfaces of Earth. The wavelengths of these UV lights are widely known for their infamous factors that causes skin damage which can potentially lead to cancer. UV radiation is part of the electromagnetic (light) spectrum that reaches the earth from the sun. It has wavelengths shorter than visible light, making it invisible to the naked eye.These wave lengths can be measured and divided into two main different categories, UVA and UVB. What are UVA rays? Most of us are exposed to large amounts of UVA throughout our lifetime. UVA rays account for up to 95 percent of the UV radiation reaching the Earth's surface. Although they are less intense and harmful in comparision to UVB, UVA rays are 30 to 50 times more prevalent, as we come into contact with them more often on a day to day basis. They are present with relatively equal intensity during all daylight hours throughout the year, and can penetrate clouds and glass.

UVA, which penetrates the skin more deeply than UVB, has long been known to play a major part in skin aging and wrinkling (photo-aging).However it was only until recently where scientists believed it did not cause significant damage in areas of the epidermis (outermost skin layer) where most skin cancers occur.

UVA is the dominant tanning ray, and we now know that tanning, whether outdoors or in a salon, causes cumulative damage over time. A tan results from injury to the skin's DNA; the skin darkens in an imperfect attempt to prevent further DNA damage. These imperfections, or mutations, can lead to skin cancer. What are UVB rays? UVB is the main and sole cause of skin reddening and sunburn. These rays tends to damage the skin's superficial epidermal layers. It also plays a key role in the development of skin cancer and a contributory role in tanning and signs of photo-aging. Its intensity varies by season, location, and time of day. The most significant amount of UVB hits Australia between 10 AM and 4 PM from September to February. However, UVB rays can burn and damage your skin all year-round, especially at high altitudes and on reflective surfaces such as snow or ice, which bounce back up to 80 percent of the rays so that they hit the skin twice. UVB rays unlike UBA rays do not significantly penetrate glass. A
FDA-Approved Sunscreens
Active Ingredient/UV Filter Name Range Covered
UVA1: 340-400 nm
UVA2: 320-340 nm
UVB: 290-320 nm
Chemical Absorbers:
Aminobenzoic acid (PABA) UVB
Avobenzone UVA1
Cinoxate UVB
Dioxybenzone UVB, UVA2
Ecamsule (Mexoryl SX) UVA2
Ensulizole (Phenylbenzimiazole Sulfonic Acid) UVB
Homosalate UVB
Meradimate (Menthyl Anthranilate) UVA2
Octocrylene UVB
Octinoxate (Octyl Methoxycinnamate) UVB
Octisalate ( Octyl Salicylate) UVB
Oxybenzone UVB, UVA2
Padimate O UVB
Sulisobenzone UVB, UVA2
Trolamine Salicylate UVB
Physical Filters:
Titanium Dioxide UVB, UVA2

However, there is no evidence that the limited number of nanoparticles used in sunscreen and cosmetics can cause any damage. At present there is little research into the general toxicity of nanoparticles with respect to damage to DNA or lungs. More evidence is needed to understand if there is any cause for concern and more research needs to be carried out by the scientific community. Although there has been discussion over the safety of nanoparticles in sunscreen it is still advise for people to wear in when exposed to the sun.

While Australia has the highest incidence of skin cancer in the world. There has been considerable media attention given to the potential health and environmental impacts that new nanotechnologies may present.

'There is more risk from not using sunscreen and getting burnt than there is from using sunscreen and the potential penetration of nanopaticles.' - Maxine McCall CSIRO. A nano partical used in sunscreens are Titanium dioxide is a molecule which are composed of one atom of titanium and two atoms of oxygen. Titanium dioxide absorbs ultraviolet light; this property makes titanium dioxide useful in sunscreens.

Titanium dioxide nanoparticles are photocatalysts, which means that they have the capability to use energy in light to catalyze reactions with other molecules at reduced temperatures. Although other photocatalytic materials are available, researchers have found that titanium dioxide provides the best performance in sunlight. Hence, it is often refered to as the best or most suitable for sunscreen along with zinc oxide. BIBLIOGRAPHY. WEBSITE: http://www.earthshare.org/2009/05/sunscreen-risks.html
WEBSITE: http://www.qm.qld.gov.au/microsites/biodiscovery/05human-impact/sunscreen-for-corals.html
WEBSITE: http://www.dummies.com/how-to/content/titanium-dioxide-nanoparticles-make-better-sunscre.html
WEBSITE: http://www.organicconsumers.org/articles/article_25816.cfm
WEBSITE: http://www.bbc.co.uk/schools/gcsebitesize/science/21c/materials_choices/nanotechnologyrev1.shtml
WEBSITE: http://www.health.gov.au/internet/main/publishing.nsf/Content/currentissue-P10000045
WEBSITE: Coral reefs are a vital compartment of the ecosystem, because it contains a vast amount of biodiversy within one large and beautfiul ecosystem. However this serene environment is constantly under threat of coral bleaching and sunscreen plays a vital part in the death of corals. An approximate 6,000 tons of sunscreen is released annually by tourists in reef areas, and because sunscreens are often petroleum based, they don’t biodegrade meaning they linger in the waters and become poisonous to organisms inhabiting the reef.

When nano particals in sunscreen come in contact with reefs, the coral becomes overly stressed, pushing out the algae living inside and leaving behind a vulnerable skeletal structure. As coral reefs lose their biological inhabitants due to toxins, pollution and increased temperatures due to global warming, they also lose their pigments, hence the term, 'coral bleaching.' Nanomaterials used in the production of sunscreen or for the consumer market is often more costly to produce in comparison to the more traditional materials but their variety of applications are increased as it widens the possibilities of new products. As the variety of applications increases the quantities also increases and according to normal economic principles, their unit cost would decrease. This same principle applies to the usage of nanotechnology used in sunscreens.
Some other economical issues that nanotechnology poses is the amount of Taxed money used to fund nanotechnology research. Since fiscal year (FY) 2001, U.S. taxpayers have spent over $4 billion on nanotechnology research. Additionally, President Bush’s budget request for FY 2006 includes an additional $1 billion for research in nanotechnology across 11 federal agencies.
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