support this site

Friday, September 21, 2007

Nanoparticle Vaccine Is Both More Effective And Less Expensive

from Sciencedaily, bioengineering researchers from the EPFL in Lausanne, Switzerland, have developed and patented a nanoparticle that can deliver vaccines more effectively, with fewer side effects, and at a fraction of the cost of current vaccine technologies.

This technology may make it possible to vaccinate against diseases like hepatitis and malaria with a single injection. And at an estimated cost of only a dollar a dose, this technology represents a real breakthrough for vaccine efforts in the developing world.

Thanks to recent advances, an immune response can be triggered with just a single protein from a virus or bacterium. Recent research has also shown that the best way to get sustained immunity is to deliver an antigen directly to specialized immune cells known as dendritic cells (DCs). Current methods have trouble obtaining an adequate immune response with a single injection and can cause side effects or even be toxic.

EPFL professors Jeff Hubbell and Melody Swartz and PhD student Sai Reddy have engineered nanoparticles that completely overcome these limitations. At a mere 25 nanometers, these particles are so tiny that once injected, they flow through the skin's extracellular matrix, making a beeline to the lymph nodes. Within minutes, they've reached a concentration of DCs thousands of times greater than in the skin. The immune response can then be extremely strong and effective.

In addition, the EPFL team has also engineered a special chemical coating for the nanoparticles that mimics the surface chemistry of a bacterial cell wall. The DCs don't recognize this as a specific invader, but do know that it's something foreign, and so a low-level, generic immune reaction known as "complement" is triggered. This results in a particularly potent immune response without the risk of unpleasant or toxic side effects.

Cost and logistics are important factors, especially for use in developing countries. Unlike other nanoparticle vaccine technologies that degrade in water and thus require expensive drying and handling procedures, the EPFL team's nanoparticles won't degrade until they are in the body. They are in liquid form and don't require refrigeration, so preparation and handling costs are reduced, and they are easy to transport.

More study is required to achieve these goals," she adds, "but we have every reason to believe this technique could be in use within five years."