Health and Medicine

Nanoparticles Deliver Three Cancer Drugs at Once

April 15, 2014 | by Lisa Winter

Photo credit: The new MIT nanoparticles consist of polymer chains (blue) and three different drug molecules — doxorubicin is red, the small green particles are camptothecin, and the larger green core contains cisplatin. Image courtesy of Jeremiah Johnson

Nanomedicine is an exciting field of study that will allow doctors to pinpoint and treat problem areas on a cell-by-cell basis for many diseases, including cancer.  While the ability to administer even one medication in a targeted fashion is incredible, researchers from MIT have developed nanoparticles that can deliver three cancer drugs at once, with the option of adding more. The research was led by Jeremiah Johnson and the results were published in the Journal of the American Chemical Society.

This targeted approach will not only get rid of all of the diseased cells but it will spare healthy cells; a sharp contrast to traditional chemotherapy. In order for traditional intravenous drugs to kill all of the cancer cells, a large amount of healthy cells are also killed. This is why many cancer patients lose their hair and experience truly horrific side effects during treatment. It would be a complete game changer if this were no longer the case.

“We think it’s the first example of a nanoparticle that carries a precise ratio of three drugs and can release those drugs in response to three distinct triggering mechanisms,” Johnson said in a press release. This triple-threat nanoparticle eliminated ovarian cancer cells better than nanoparticles which utilized either one or two medications. The design also allows for modification to include additional drugs as well. 

The development of these nanoparticles has traditionally been hindered by where the drugs can be attached in the proper quantities. Some designs make an enclosure and tuck the medicine inside, which only allows for one medication. Attaching them to the outside can be done with two drugs, but is extremely difficult. 

In order for a particle to deliver three drugs, Johnson’s lab had to take a completely different approach to the problem. Rather than using pieces to carry the drug, the particle is assembled from pieces that are the drug. Carefully regulated construction allows the pieces to fit together while maintaining the proper ratios of medication. The drug molecules are attached to a linking unit and then put into a polymer chain to protect the particles from breaking down in the body before it can enter the cell. Once the drugs have been delivered, the chain easily breaks down.

The team is moving forward in their research and has begun using this technique in animal models. They are also seeking to add a fourth drug to the structure. Their structure will also allow the ratios to be reconfigured as needed, to treat patients on an individual basis or to ensure that each medication is actually being useful.

 

The particles were designed to release doxorubicin when exposed to ultraviolet light. Here, ovarian cancer cells turn red as the doxorubicin is released over time. Image courtesy of Erik Dreaden and Kevin Shopsowitz

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