The promise of nanotechnology

The state of the art holds potential for reshaping diagnosis, treatment

 

Nanotechnology (U017)

Noninvasive biopsies obtained by nanoparticles that sample tissue and are captured magnetically; microneedle patches that analyze biological activity and deliver medications and vaccines; nanoencapsulated corticosteroids that are delivered only to the site of inflammation. These are all part of the promise of nanotechnology that will be explored Friday.

“The state of the art in nanotechnology will allow for precise, rapid, and less invasive diagnosis of skin disease and more powerful therapies with fewer unintended side effects,” said Adnan Nasir, MD, PhD, who will explain the potential of using nanoparticles for diagnosis and treatment.

Dr. Nasir, a clinical associate professor in the department of dermatology at the University of North Carolina, Chapel Hill, will explain the scientific advances of nanotechnology and how it is making its way into consumer products for skin protection, skin health, and skin rejuvenation.

New applications

“Some applications, such as sunscreens, cosmetics, retinoids, and topical emollients, are already available. Others have not made it to the market yet, but they are being studied in trials. The hope is that within a few years we will have them at our disposal,” said Dr. Nasir, the director of dermatology research at Wake Research Associates, Raleigh, North Carolina.

One use for nanotechnology being investigated is to noninvasively diagnose skin disease. Nanoparticles could be injected into the body and guided optically or magnetically to the area with a problem, such as a tumor or a rash.

“They can be externally activated to take small samples of tissue, and then they can be harvested magnetically or filtered,” Dr. Nasir said of nanoparticles. “The tissue that was harvested can be analyzed. That is a minimally invasive or noninvasive way of getting a biopsy.”

Microneedle patches

Another nanotechnology tool is microneedles in patches that create minute openings in the skin. A patch could be applied to an area of the body requiring a diagnosis so the needles could release interstitial or cellular fluid that could be analyzed for that diagnosis, he said.

Microneedle patches have been shown to deliver vaccines, such as the flu vaccine.

“I can envision a time when we will have a microneedle patch vaccine for dermatologic indications,” Dr. Nasir said. “Examples of ones being developed are for herpes zoster, herpes simplex virus, and human papillomavirus. Microneedle patches have recently demonstrated enhanced efficacy and reduced side effects in the delivery of aminolevulinic acid for photodynamic therapy. Companies developing microneedle technology are seeking input from dermatologists for potential therapeutic indications.”

Microencapsulation

Another treatment being studied is the use of microencapsulated or nanoencapsulated corticosteroids that are released in the circulation in the area of disease. Side effects from the steroids would be greatly reduced because they would be focused only in the area of disease.

“Inflammatory disease recruits new blood vessels, which are neoangiogenic blood vessels,” Dr. Nasir said. “They have tiny holes or windows that are in the size range of 100-200 nanometers. If you encapsulate corticosteroids in capsules that size, they remain in the circulation but the active drug is not released. The steroids are only slowly leaked out where the new vessels have these windows in them, and that is in areas of inflammation. A similar principle operates in neoangiogenesis associated with malignancy.”

Yet another possible treatment would be to encapsulate medicines in liposomes that could target the skin without going deeper into the dermis. This delivery method could be used for corticosteroids or an immunosuppressive — such as methotrexate, he said.

“You can also deliver medications so they are less irritating. For example, retinoids for acne and aging of skin are irritating to the skin,” Dr. Nasir said. “An interesting phenomenon of nanoencapsulation of retinoids is that the irritation goes away.”

Potential for the future

The list of possible advances is long, and it includes targeted delivery of emollients for atopic dermatitis, nanocosmeceuticals, and treatments to repair damage to the skin after sun exposure.

“This is a burgeoning field in medicine and dermatology. Nanoparticles are already being used in a number of consumer products,” Dr. Nasir said. “They are already being used in over-the-counter and prescription dermatologic products. There is even potential for combining and reviving therapies that have been limited because they are incompatible with one another or because of their relatively crude mechanisms of action.”

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