The exosomes, injected into the blood, act as 'drugs vehicles' - crossing the normally impermeable blood-brain barrier to the brain where they are needed.
"The message is getting across but there is still a hard core of motorists out there who are totally irresponsible, who put their own lives, the lives of their passengers and the lives of other road users at risk by taking drugs and getting behind the wheel of motor vehicles, " he said.