Us humans are always looking for the easy way out. If we can get someone else to do our dirty work for us, so much the better, which is why drug dealers rely on mules to ship merchandise for them. One of the trickiest things to do in medical science is smuggling drugs or nanoprobes into the body to the specific area they are required. Many of these probes and drugs are considered foreign objects to the body, and as such will be removed by the body’s equivilent of a customs officer – the white blood cells. Many treatments are therefore prevented from getting to the site of action, and so are effectively useless.
In the past, scientists have tried to disguise these invading objects, by wrapping them up in polyethylene or something similar. However, these artificial materials are also easily recognised by the body’s immune system and quickly destroyed. Scientists, publishing their work in the journal Nano Letters, have successfully managed to get someone else to do the difficult job of smuggling in drugs and nanoprobes – our own cells.
Living cells have the ability to take in material from the outside world by extending its cell membrane and enveloping the item in question. Once inside the cell, the item becomes surrounded in its own protective bubble, known as an endosome. White blood cells use this ability to devour and digest rogue bacteria that may have found their way into your body. These are also the cells that annoyingly destroy the drugs and nanoprobes we want to administer to patients.
Cells also have the ability to do this in reverse. They can produce these bubbles from their cell membrane and release them, and their contents, into the external environment. Hormones, antibodies, enzymes, and more are all released from cells to do vital functions.
It was this ability of the cell to package and release chemicals that the authors of the paper wanted to exploit. If one could create a cell that could package the drugs you wanted packaging, one could circumvent the irritating behaviour of the immune system of destroying foreign objects. This is because the bubbles of cell membrane, known as cell membrane capsules, are invisible to the immune system; they are made from the same stuff as your own cells and so wont be treated as foreign. The can, therefore, stay in the body for much longer than artificial capsules. Its hoped this research will lead to treatments and diagnoses for a huge number of diseases.
Drug smuggling has never looked so virtuous.
Image from serhanlab.bwh.harvard.edu