Posts Tagged ‘Nanoparticle’

The polymer nanocomposites industry.: An article from: Nanoparticle News

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This digital document is an article from Nanoparticle News, published by Business Communications Company, Inc. on November 1, 2003. The length of the article is 1600 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.

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Title: The pol… More >>

The polymer nanocomposites industry.: An article from: Nanoparticle News

Monte Carlo Simulations of Nanoparticle Filled Polymer Nanocomposites – A Novel Approach to Investigate the Effect of Nanofillers on the … Matrix: Chain Dimensions go up or down?

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In the last decade, nanofiller particles have prompted much attention and become a developing field in polymer processing applications. A particle size at nano scale offers an enormous amount of surface area and a great dispersion behavior. Thus, the use of nanofillers is very promising so as to improve the physical properties more effectively than conventional type of fillers. The change in such properties can be related to the subsequent conformational changes, bu… More >>

Monte Carlo Simulations of Nanoparticle Filled Polymer Nanocomposites – A Novel Approach to Investigate the Effect of Nanofillers on the … Matrix: Chain Dimensions go up or down?

Know How Tiny Nanoparticle Capsules Deliver Medicines

A tiny particle syringe composed of polymer layers and nanoparticles may provide drug delivery that targets diseased cells without harming the rest of the body, according to a team of chemical engineers. This delivery system could be robust and flexible enough to deliver a variety of substances.

“People probably fear the effects of some treatments more than they fear the disease they treat,” says Huda A. Jerri, graduate student, chemical engineering. “The drugs are poison. Treatment is a matter of dosage so that it kills the cancer and not the patient. Targeted treatment becomes very important.”

Newer approaches to drug delivery include particles that find specific cells, latch on and release their drugs. Another approach allows the cells to engulf the particles, taking them into the cell and releasing the drug. However, the requirements for these delivery systems are complicated and challenging to implement.

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The Penn State researchers’ approach produces a more universal delivery system, a tiny spherical container averaging less than 5 microns or the diameter of the smallest pollen grains.

The spheres are formed around solid microparticles that are either the drug to be delivered or a substance that can be removed later leaving a hollow sphere for liquid drugs. They reported their results online in Soft Matter.

Alternating positive and negative layers of material form the microcapsules. The capsules are created while attached to a flat surface so the section of the sphere touching the surface is not coated, leaving about 5 percent of the surface as an escape area for the drugs. The microcapsule, excluding the exit hole, is then covered in a slippery, non-stick barrier coating.

“These are not the first microcapsules for drug delivery developed, but a previous attempt had surfaces that stuck together and clumped,” says Velegol. “We also designed the tiny hole in the sphere for controlled delivery and that is a new development.”

Targeted drug delivery systems release their drug from the moment they enter the body. The microsyringes, however, while releasing material continuously, do so only from the tiny hole in their surface and not from the other 95 percent of the sphere’s surface. This will concentrate the drug at the target and reduce the amount of toxins circulating in the body.

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Sunscreen Confusion – Is Nanoparticle Sunscreen Safe?

Zinc oxide is the most effective approved mineral based ingredient to protect the skin from both UVA and UVB damage. This mineral forms a physical barrier on the skin, reflecting UVB and UVA rays from penetrating down to the deeper layers of skin. It is less irritating and safer than chemical sunscreens and has a wider range of protection from UV rays. According to the Environmental Working Group: “We found that consumers using sunscreens without zinc and titanium would be exposed to an average of 20% more UVA radiation — with increased risks for UVA-induced skin damage, premature aging, wrinkling, and UV-induced immune system damage — than consumers using zinc- and titanium-based products.”

The common complaint by users of sunscreen products containing zinc has been regarding the white coating it leaves on the skin. This is where nanoparticles come in – particles that are smaller than 100 nanometers (or “nm” – a nanometer is roughly half the size of a strand of DNA). Zinc is shrunk into tiny particles measuring under 100nm, providing better protection and eliminating the white cast.

Nanoparticles have come under close scrutiny by some watchdog groups concerned over the possible health effects of nanoparticles entering the deep tissues, blood or lungs. Research on the subject to date has had varied outcomes. The level of nano-scale zinc found in the body has ranged from zero to little, or greater amounts, dependant on how it is introduced to the system and its size. In their most recent sunscreen guide, the Environmental Working Group (EWG) writes:

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In 15 peer-reviewed studies, nanosize zinc and titanium were shown not to penetrate through unbroken skin at concentrations exceeding 1.5%. A recent review for the EU decision-making body found that, “There is currently little evidence from skin penetration studies that dermal applications of metal oxide nanoparticles used in sunscreens lead to systemic exposure” (Börm 2006).

The majority of sunscreens available for purchase in the US include nanoscale zinc, typically 30 to 200 nm in size. And because labeling laws are unclear where nanoparticles are concerned, it can be difficult to know if you are purchasing a product that contains nanoparticle ingredients or not. The FDA has not yet set standards for nanoparticle claims or defined the minimum size of a nanoparticle. This has caused some individuals and groups to recommend consumers avoid zinc and titanium-based sunscreens altogether.

But this recommendation is not necessarily the safest option. A study by The EWG shows that those using chemical sunscreens are exposed to both greater UV radiation and more hazardous ingredients. Micronized zinc is shown to provide safer protection than either chemical sunscreens or unprotected sun exposure.

But for maximum safety, zinc oxide and titanium dioxide must be coated in order to render them inert. Make sure you purchase your organic sunscreen or all natural sunscreen from a company that uses coated zinc and titanium. Many manufacturers use uncoated zinc. Uncoated zinc has approx 3-5% photoreactivity and may produce free radicals, but coated zinc is below 1% photoreactivity and the chance of free radical production is greatly reduced.

Nanoparticle emulsion can speed up healing of cold sore ?

In accordance to a news source from San Francisco dated March 12, 2009, a randomized clinical trial has managed to heal cold sores more than a day faster when treated with an investigational nanoparticle emulsion that disrupts the viral membrane. Such news is great to many cold sore sufferers. It is a new break through to remedies for cold sores. Various remedies for cold sores are found in the net and continual improvements to these remedies are always welcome to many.

The news from the American Academy of Dermatology meeting said that when using the topical NB-001 on cold sore patients who are in the prodomal stage of a herpes labialis recurrence, it would speeds up the healing by almost two full days. Such news was great, as the mental stress brought by cold sores is unmeasurable especially when one got to got to face the public. The stigma of being labled as a cold sore virus patient is already stressful enough.

Below are some of the notes from the said academy meeting:

“In subjects with no lesion at baseline, the time to healing was 3.6 days, providing a significant clinical advantage over current topical and systemic agents,” the investigators concluded in a poster presentation.

“The novel physical mechanism of action renders the emergence of drug resistance highly unlikely, making NB-001 an ideal candidate for widespread treatment of common conditions, such as herpes labialis.”

More than 80% of adults have latent herpes simplex virus-1 (HSV-1) in facial ganglia. In one-third of these people, viral reactivation leads to recurrent lesions on the lips and surrounding skin.

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Current topical therapies for herpes labialis are largely ineffective, and physicians are reluctant to prescribe oral medication, partly because of concerns about the emergence of drug-resistant strains of HSV-1, the authors said.

NB-001 is an investigational nanoemulsion consisting of high-energy, nanometer-size droplets containing cetylpyridinium chloride, polysorbate, and oil.

When applied to the skin, the droplets enter the epidermis and dermis, but their size prevents entry into epithelial-cell junctions, eliminating the potential for skin irritation or systemic absorption, the investigators continued.

Upon reactivation, latent HSV-1 migrates down nerve endings, existing at the dermal-epidermal junction. At that point, the nanoemulsion droplets surround the virus and fuse with the viral envelope, causing membrane disruption and viral destruction.

Investigators tested NB-001 in 919 adults with a history of HSV-1 reactivation, resulting in an average of three cold-sore outbreaks a year.

Study participants received locked medication kits containing either the NB-001 vehicle or one of three concentrations of the active nanoemulsion (0.1%, 0.3%, and 0.5%).

At the first sign of a recurrence, participants contacted investigators and received a code to unlock the medication kit and apply 200 µL of therapy five times a day for a maximum of five days.

During an outbreak, participants were assessed daily until the lesion healed or was aborted.

A total of 482 participants from 28 sites in the U.S. had cold-sore outbreaks. At the daily assessment during an outbreak, investigators rated the lesion stage as prodrome, erythema, blister, ulcer, scab, or healed. They defined healing as the return of normal skin color and no evidence of scab.

All three formulations of NB-001 led to faster healing of cold sores compared with vehicle, which was associated with a median healing time of 6.0 days and a mean of 6.7 days. However, only the 0.3% concentration significantly reduced healing time (a median of 5.0 days and a mean of 5.4, P=0.0064).

“This treatment effect is higher than that reported for the current topical therapies and is equal to that reported for high-dose oral nucleoside regimens,” the investigators said.

A subset analysis limited to patients who began treatment in the prodromal or erythematous stage showed that patients using the 0.3% nanoemulsion had a mean healing time of 3.6 days, representing about a two-day improvement over vehicle.

The findings supported prior experiments in which the 0.3% emulsion achieved the greatest penetration in cadaver tissue.

No safety issues with the nanoemulsion arose during the study.

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