Bacteria that respond to magnetic fields and low oxygen levels target hard-to-treat tumors

Cancer cells in a growing tumour consume large amounts of oxygen and parts of the tumour will become starved of oxygen – or hypoxic. It is notoriously difficult to deliver tumour-destroying drugs to these hypoxic regions using conventional pharmaceutical nanocarriers, such as liposomes, micelles and polymeric nanoparticles.
Now, researchers from the NanoRobotics Laboratory at the Polytechnique Montréal – including researchers at McGill University – have done experiments that show how magneto-aerotactic bacteria Magnetoccus marinus (MC-1) can be used to deliver drugs to hard-to-reach parts of tumours. With further development, the method could be used to treat a variety of solid tumours, which account for roughly 85% of all cancers.
A MC-1 bacterium has a chain of magnetic nanoparticles that acts like a microscopic magnetic compass needle. The bacteria live in saltwater estuaries in the northern hemisphere, where they use the Earths's geomagnetic field to point them towards deeper water with low oxygen concentrations. The microbes do this because they thrive where oxygen concentrations are low. Indeed, the oxygen levels found in hypoxic regions of a tumour – about 0.5% – are perfect for MC-1.
The researchers created an artificial environment to allow these bacteria to migrate towards the hypoxic regions of tumours in live mice with colorectal cancers.
These bacteria can be used as general transport vehicles to carry a huge variety of therapeutic agents, such as various drug molecules, radiotherapeutic agents, stem cells and immunotherapeutics.

http://physicsworld.com/cws/article/news/2016/aug/23/magnetic-bacteria-target-hard-to-treat-tumours