In another step forward in the field of plasmonics research researchers at Duke University in the USA, under the leadership of Dr. Anne Lazarides, have created gold-DNA nanostructures that can be used as optical biosensors.

The nanostructures comprise core gold nanoparticles with a number of smaller particles “tethered” to them by short strands of DNA. These self-assemble in solution under closely-controlled conditions. On encountering DNA in biological material in a biosensing situation, the strands of DNA expand or contract, moving the “moons” and changing the optical properties of the particles which can then be detected. The nanoparticle clusters are also small enough to pass through cell membranes widely expanding the range of possible biosensing applications.

For more information see the Duke University press release.

Posted: July 9th, 2008 under Advanced medtech, Nanomedicine, Nanotechnology.
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The unwanted growth of blood vessels is a key feature of a number of serious diseases including cancers, arthritis and macular degeneration. While there are a number of drugs that effectively inhibit the angiogenesis, or growth, of these vessels some only target a limited number of receptor or have unacceptable side affects

A team at Boston Children’s Hospital have now succeeded in reformulating a broad-spectrum angiogenesis inhibitor, TNP-470, using a nanotechnology approach into a form that can be taken orally and that has the potential to be used as a preventative or maintenance therapy for a variety of cancers. TNP-470 was derived some 20 years ago from the fungus Fumagillin and has a very broad spectrum of anti-angiogenic activity including against some metastatic cancers. Because of serious neurological side effects at high doses however trials were stopped during the 1990s.

The team, led by Dr Ofra Benny, used nanoscale polymeric micelles to encapsulate TNP-470 molecules and also incorporated PEG and PLA chains that protect the drug from the stomach’s acidic environment and allow the drug to be absorbed into the bloodstream and to reach the tumour sites when taken orally. The new formulation, named Lodamin, appears to retain TNP-470’s efficacy and broad spectrum activity against aggressive tumour models but without the neurological side effects.

Further clinical development of the nanoformulated drug is now being investigated. 

Further information available at the Boston Children’s Hospital website.

Posted: July 8th, 2008 under Nanomedicine.
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University of California researchers have developed a new nanoparticulate drug delivery system that can be used to target hard-to-treat metastatic cancers with much lower quantities of highly toxic chemotherapeutic agents. 

The team, based at UC San Diego and led by Professor David Cheresh, targeted the protein marker integrin avB3, which is associated with angiogenesis in tumours, with a lipid-polymer based 100nm particle carrying a paylod of doxorubicin. The therapeutic effects were observed to be much more effective in inhibiting the growth of secondary metastatic lesions than in attacking the primary tumours in pancreatic and kidney tumours in mice at dosage levels 15 time below the normal systemic dose, which can cause damage to normal healthy tissues.

The approach may have considerable significance as metastatic lesions are commonly difficult to treat and can frequently be the cause of death rather than the primary tumour in many types of cancer, and also because of the greatly reduced quantity of chemotherapeutic agent required.

More information available in the UC San Diego press release.

Posted: July 8th, 2008 under Nanomedicine.
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