Could insects become biosensors of the future?
With the help of a Marie Skłodowska-Curie Fellowship grant, Dr Vincenzo Di Ilio was able to encourage substance addiction in a certain species of cockroach. If this addiction can be positively associated with a certain odour, these insects could one day be used as living biosensors to carry out a range of useful activities. ‘The inspiration for this project came from the identification of a problem that continues to cause immense suffering and economic hardship around the world - the legacy of landmines,’ explains Di Ilio. ‘These small plastic devices remain in the ground after wars, resulting in accidents and death and leaving arable land unusable. Detection and clearance remains dangerous, impractical and expensive.’ These devices are often triggered by little more than 300g of pressure so using dogs to sniff out landmines is not possible. Di Ilio’s idea was to investigate the possibility of using insects instead, which could one day be tagged and “trained” to find explosives. This would enable experts to then identify the location of landmines and send in robots to remove them. Insects as biosensors Di Ilio notes that getting to this point will take years, and stresses that the focus of the ACTING (Addiction of Insects for Biosensoring) project was first and foremost to assess the potential of inducing insects to find a particular odour. This process began by selecting the ideal candidate for the job. ‘Not all insect olfactory systems are the same,’ he says. ‘We chose the German cockroach because it is sensitive to a wide spectrum of volatile chemicals, and we figured this insect could be used to find explosives.’ The next challenge was finding a way of limiting the animal’s interest to just one smell. Cockroaches are voracious eaters, but of course do not eat plastic explosives. ‘My idea here was to use drugs to alter the insect’s perception of its environment,’ explains Di Ilio. ‘We sought to induce addiction in insects, and associate drug intake with a certain odour. This was the key objective of my research.’ Given the difficulty of securing licences for drugs such as morphine and heroin, Di Ilio began his research by giving cockroaches tiny doses of nicotine. Cockroaches were found to be more sensitive to cigarette smoke than extracted nicotine, and some cues of addiction were successfully recorded. ‘I’m currently preparing a paper on these results, due to be published shortly,’ says Di Ilio. ‘But towards the end of my Marie Curie grant, I was able to obtain a licence to use methadone and heroin on cockroaches, and preliminary tests recorded clear cues of addiction, which is very exciting. This is the point where we are now.’ World of potential Moving forward, Di Ilio is looking to secure further funding in order to find out how induced addiction can best be exploited, and how it can be properly controlled. From an academic perspective, the ACTING project’s early stage research could open up new opportunities to understand drug addiction and the behavioural changes this can cause. It might also help researchers understand how insects perceive their surrounding environment. ‘All these preliminary results first need to be verified to validate our hypothesis, but I think there is potential here,’ he says. ‘We could imagine associating addiction in insects to, say, their ability to detect tiny changes in the odour of blood, which might lead to early diagnoses of diseases like tuberculosis. Fruit growers would be interested in the early detection of bacterial disease. You could use insects as biosensors for many things.’
Keywords
ACTING, insects, addiction, Marie Curie, tuberculosis, blood, landmines, diagnoses, methadone, heroin, cockroach