Scientists have developed nanometer-sized ‘cargo ships’ that can sail throughout the body via the bloodstream without immediate detection from the body’s immune radar system and ferry their cargo of anti-cancer drugs and markers into tumors that might otherwise go untreated or undetected.
This delivery system is in an early stage of development, so far tested only on mice.
In a forthcoming issue of the Germany-based chemistry journal Angewandte Chemie, scientists at UC San Diego, UC Santa Barbara and MIT report that their nano-cargo-ship system integrates therapeutic and diagnostic functions into a single device that avoids rapid removal by the body’s natural immune system. Their paper is now accessible in an early online version here.
“The idea involves encapsulating imaging agents and drugs into a protective ‘mother ship’ that evades the natural processes that normally would remove these payloads if they were unprotected,” said Michael Sailor, a professor of chemistry and biochemistry at UCSD who headed the team of chemists, biologists and engineers that turned the fanciful concept into reality. “These mother ships are only 50 nanometers in diameter, or 1,000 times smaller than the diameter of a human hair, and are equipped with an array of molecules on their surfaces that enable them to find and penetrate tumor cells in the body.”
Just because they can put molecules on the surface of these nanodevices does not mean they know which molecules to attach in order to maximize selective targeting of only cancer cells. That's a whole other problem which we really need excellent solutions for. But assuming a solution to that latter problem then these nanodevices could carry chemotherapy toxins into cancer cells to selectively kill only cancer cells.
These microscopic cargo ships could one day provide the means to more effectively deliver toxic anti-cancer drugs to tumors in high concentrations without negatively impacting other parts of the body.
They tested imaging enhancement payloads in mice. But this mechanism could also be used to deliver toxic chemotherapy to tumours.
The researchers loaded their ships with three payloads before injecting them in the mice. Two types of nanoparticles, superparamagnetic iron oxide and fluorescent quantum dots, were placed in the ship’s cargo hold, along with the anti-cancer drug doxorubicin. The iron oxide nanoparticles allow the ships to show up in a Magnetic Resonance Imaging, or MRI, scan, while the quantum dots can be seen with another type of imaging tool, a fluorescence scanner.
Their bigger problem is probably going to be how to get highly selective on just which cells these packages will enter.
The researchers are now working on developing ways to chemically treat the exteriors of the nano ships with specific chemical “zip codes,” that will allow them to be delivered to specific tumors, organs and other sites in the body.
Can this approach cure cancer? The question will depend in part on whether the surfaces of cancer cells look different enough from normal to provide highly selective delivery into cancer cells.
But this approach could be enhanced with smart payloads. Imagine a payload that includes a genetic sequence. It could get activated only in cells which internally look like cancer cells. So the package might make it into cancerous and non-cancerous cells but only do real damage in cancer cells. But that would probably be a bigger payload than a chemotherapy agent. So that makes packaging harder to do.
Once we can cure cancer and repair our internal organs with stem cells and replacement organs our big problem is going to be brain aging. Alzheimer's, Parkinson's, strokes, and other causes of dementia and brain decay will all need solutions. Alzheimer's might be solved even before cancer. But the other diseases of aging brains will be tougher problems to solve.
|Share |||Randall Parker, 2008 September 14 12:24 AM Nanotech for Biotech|