Interesting results have been published, open access, in Science Advances. The work gives details of the first ever in vivo trial of self-fuelled nanoparticles being used to transport cargo through blood. In English, they used gas propelled blobs to deliver coagulant to the site of a wound and help stop the bleeding.
Trauma is still one of the world’s biggest killers of people, especially young people, and part of the reason for that is that sometimes it’s just too difficult to deliver the necessary drugs to the wound. If the wound is deep, or next to an area you can’t poke around in like the brain, or if the flow of blood pushes out whatever treatment you’re trying to apply then it can be almost impossible to seal it.
The new system works by taking particles of CaCO3, calcium carbonate, the fizzy part in an antacid tablet, and adding the drug of interest to it; in this case thrombin to help blood to clot. When the particle is in a water based liquid, such as blood, then it reacts by releasing CO2 gas, this causes it to actively propel itself. Their top speed was clocked at 1.5cm/sec; not exactly the speed of light but much faster than any other technology tried so far.
The Canadian team of researchers tested the system in two animal models, mouse and pig. In the mouse they tested it on amputated tails and punctured livers and in the pigs on a punctured femoral artery. All animals were anaesthetised before testing. In the mice who had the tips of their tails amputated 2 out of 8 stopped bleeding spontaneously without any treatment; 3 out of 9 stopped when treated with gauze that did not contain the new propelled thrombin; and 8 out of 9 stopped bleeding when treated with gauze that did contain the new treatment. In the pigs, none survived without treatment; 2 out of 5 survived when treated with normal gauze and all of them survived when the new treatment was used. Trial numbers were admittedly small but these are some very promising numbers that certainly warrant further, larger trials.
There are many areas of potential applications for this new technology. One of the leading killers of women during childbirth is still postpartum haemorrhage which is very difficult to treat even in modern hospitals, nevermind in the types of hospitals that most of the world has to use. On the battlefield could be another area where huge benefits could be felt but also just as another tool in the modern surgeon’s box of tricks. One major advantage to the new treatment is that it is easily scalable and quite cheap; who knows, maybe we’ll be seeing this in A&Es and first aid kits all over the world a few years from now. Let’s hope so.