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Researchers create modular, multi-functional drug delivery system

Medical Research News
Published: Monday, 8-Oct-2007

There are two aspects to creating an effective drug: finding a chemical compound that has the desired biological effect and minimal side-effects and then delivering it to the right place in the body for it to do its job.

With the support from a $478,000, five-year CAREER award from the National Science Foundation, Eva Harth is tackling the second part of this problem. She is creating a modular, multi-functional drug delivery system that promises simultaneously to enhance the effectiveness and reduce undesirable side-effects of a number of different drugs.

(NSF's Faculty Early Career Development awards are the agency's most prestigious honor for junior faculty members and are given to individuals judged most likely to become the academic leaders of the 21st century.)

Harth, who is an assistant professor of chemistry at Vanderbilt University, has created a "nanosponge" specially designed to carry large numbers of drug molecules. She has also discovered a "molecular transporter" that, when attached to the nanosponge, carries it and its cargo across biological barriers into specific intracellular compartments, which are very difficult places for most drugs to reach. She has shown that her system can reach another difficult target: the brain. Experiments have shown that it can pass through the brain-blood barrier. In addition, she has: successfully attached a special "targeting unit" that delivers drugs to the surface of tumors in the lungs, brain and spinal cord and even developed a "light kit" for her delivery system - fluorescent tags that researchers can use to monitor where it goes.

Harth has taken a different approach from other researchers working on nanotechnology for drug development. Instead of trying to encapsulate drugs in nanoscale containers, she decided to create a nanoparticle that had a large number of surface sites where drug molecules could be attached. To do so, she adopted a method that uses extensive internal cross-linking to scrunch a long, linear molecule into a sphere about 10 nanometers in diameter, about the size of a protein. Nanoparticles like this are called nanosponges.

"We can really load this up with a large number of drug molecules," she says.

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