Macrophages go backpacking to deliver drugs

Michael Berger, writing in Nanowerk, gives us an update on the wonderful world of macrophages--white blood cells that act as a cleanup crew against disease and could be harnessed as an ideal drug-delivery device. In fact, it's been done already, as Berger points out, with macrophages delivering nanosized drugs to treat HIV, brain disorders and solid tumors. But with all these previous successes, there has been trouble with slow drug-release rates and drug degradation. Now, Nanowerk reports, these limitations are being overcome through the use of "cellular backpacks" that remain on the macrophage's surface and are phagocytosis resistant, meaning they avoid being munched on by the macrophages.

Samir Mitragoti, a professor in the Department of Chemical Engineering at the University of California, Santa Barbara, and collaborators from MIT, say these backpacks represent a new way of thinking about drug delivery. "These characteristics point to new possibilities in creating cell-based bio-hybrid devices that leverage both the functions of the encapsulated cargo--drugs, nanoparticles, etc.--and the native functions of the cell," Mitragoti said.

The advantage of the backpack method, Mitragoti said, is that not only does the drug being delivered avoid being swallowed by the macrophage, but also the backpack does not interfere with the macrophage's cellular function. That means one does not interfere with the other, and each can do their own thing as they fight disease.

- read Michael Berger's spotlight in Nanowerk
- and more on the backpacks in this abstract in Advanced Materials