A group led by Professor Mathias O. Senge from Trinity’s School of Chemistry will join scientists across Europe to develop next generation “chemical noses”. These smart electronic devices will be able to sense and remove harmful toxins before they are released into the environment. The initiative is a part of a collaborative €2.9 million Horizon2020 FET-OPEN project (INITIO).
Pollutants in the environment are becoming an ever-increasing problem. When harmful particles and gases in the environment reach dangerous levels, this can result in rising temperatures and an increase in the risk of diseases spreading. The World Health Organisation (WHO) attributed air pollution as the cause of 29% of all deaths from lung cancer, and 24% of all deaths from a stroke. The development of effective tools to deal with the identification and removal of pollutants in the air is of vital importance in addressing these problems. The removal of harmful toxins from drugs and pesticides, however, has proved increasingly challenging.
One relatively unknown reason for this is that many pesticides or pharmaceutical drugs that enter the environment, and which display a large resistivity to being biodegraded, are “chiral”. Chirality is a geometric property of some molecules whereby they exist in two non-superimposable forms, like left and right hands. For example, the scent of oranges and lemons differ due to chirality of the ‘limonene’ molecule. Oranges have the left-handed version of the molecule while lemons have the right-handed version. Ibuprofen contains both forms of chirality, but only one is active. This molecular quirk makes it difficult to identify and remove many of these pollutants, and it also influences their environmental impact. Left-hand pollutants may do more damage than right-hand molecules, and they may degrade differently, making it more difficult to identify and remove them. Chiral pollutants are found in pesticides, herbicides, fungicides, freon substitutes, dyes, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, antibiotics, and many other drugs. In most cases, their environmental impact is unknown. Being able to identify which molecules are present is of great importance in treating air pollution.
“Left-hand pollutants may do more damage than right-hand molecules and they may degrade differently, making it more difficult to identify and remove them.”
The collaborating INITIO consortium will address this major issue by first engineering molecules that act as receptors that recognise specific pollutants. The receptors will then be integrated with smart nanostructures to create devices that can be deployed directly in the field to detect and destroy the pollutants. These devices will essentially function as “chemical noses” by sniffing out the toxins. Once they have been sniffed out and identified, they can be removed and/or destroyed.
Olfactory receptors, also known as smell receptors, are proteins which are responsible for the detection of odorants, giving rise to our own sense of smell. The wide range of odors which the nose is able to detect is due to a mechanism known as molecular recognition. This allows us to discriminate between a multitude of odors present in extremely small quantities with complex structures. A “chemical nose” is a device which mimics the molecular recognition through synthetic receptors which are synthesised in laboratories. The interaction between the sensor and the molecule being detected generates a distinct pattern. Just like our own noses, these devices do not require previous built-in knowledge about various substances in order to detect them, they can instead be trained to recognise different substances.
The Irish group, headed by Professor Senge, Chair of Organic Chemistry at Trinity, will build the molecules that act as the sensors in the chemical noses. The sensors will employ porphyrin, an organic compound often dubbed “the pigment of life”. Porphyrin has been widely studied in attempts to mimic its properties in nature, it is responsible for the red colour in haemoglobin in blood and for the green colour of chlorophyll in plants. Porphyrins boast the ability to host almost all metal ions in the periodic table. The properties of the porphyrin change upon interaction with the substance being detected. These changes are then translated into a signal which may be in the form of a colour change or an electric signal, indicating the presence of a substrate. The tunable detection properties of porphyrins and their ability to detect a wide range of substances make them attractive candidates for their use in sensors. They are able to sense liquid and gas phase substances such as carbon dioxide, dopamine, and other neurotransmitters, pollutants, and explosives through a range of interactions. Using chemical methods which have recently been developed at Trinity, the porphyrin-based sensors will flag the presence of specific pollutants by changing their colour when coming into contact with them.
“Just like our own noses, these devices do not require previous built-in knowledge about various substances in order to detect them, they can instead be trained to recognise different substances.”
Professor Senge said: “This is a truly exciting award for us as the FET-OPEN programme aims to establish European leadership in the early exploration of future technologies. It combines our leading expertise in porphyrin chemistry with that of international collaborators to tackle a fundamental real-world problem which increases in severity every year.
Environmental issues, such as global warming, are on everybody’s radar, but the increasing danger from chiral pharmaceutical and agrochemical pollutants is often overlooked. We can now translate our basic research on porphyrins of the past 15 years into a field-capable technology which can have an impact in everyday life. It is also an excellent example of how crucial national fundamental science funding is. Our basic research has been generously funded by Science Foundation Ireland (SFI) since moving to Ireland in 2005, only this enabled us for transformative international collaborative programs such as INITIO targeting tangible practical applications.”
“We can now translate our basic research on porphyrins of the past 15 years into a field-capable technology which can have an impact on everyday life.”
Researchers from Trinity, five other universities, and experts from two small and medium enterprises (SMEs) will be working together in the development of the chemical noses. The other groups involved are the University of Tor Vergata and the University of Salento in Italy, who will adapt their expertise in developing chemical noses for the detection of cancer, and chemical, biological, radiological, or nuclear materials (CBRN), along with other experts from the University of Jyväskylä in Finland, the Institute of Chemistry and Biology of Membranes and Nano-objects at the University of Bordeaux, France, and Tallinn University of Technology in Estonia. Two private companies are also involved in the project; Interspectrum OU from Estonia, and Eurochem Italia srl from Italy.