Mouse Urine Unlocks New Generation of Sensors

Inspired by animals’ delicate sense of smell and the way mice mark their territory, a team of artificial olfaction researchers is using proteins in mouse urine to develop a powerful new generation of biologically-inspired sensors with potential applications for
environmental monitoring. A thousand-fold increase in sensor sensitivity has been demonstrated using mouse Major Urinary Proteins (MUPs) coated on a traditional piezoelectric crystal.
“MUPs are giving us very high sensitivity and selectivity – at levels that are unachievable with conventional sensing,” says Prof Krishna Persaud at Manchester University, a lead researcher in the EU-funded artificial olfaction research network GOSPEL (Germany).
“Classical electronic sensing methods had reached their limit, but the whole field of artificial olfaction has been energised by rapid advances inmolecular biology and genetics.”
Mice secrete a phenomenal amount of protein in their urine – up to 40mg per ml – a huge release of energy for a tiny animal. MUPs are part of a protein family with a cage-like structure, which traps odorant molecules and then releases them slowly.
This helps mice to mark and defend their territory, and it is this feature which makes MUPs stable and useful as a biosensor. The team applied MUPs to piezoelectric materials, which resonate with a precise frequency when an electric potential is applied. Target molecules were shown to bind to the MUP coating, changing the mass of the material and altering its resonant frequency.
The new sensors have many potential applications, though will first be applied to environmental monitoring. They work well in water so may be used to detect oestrogen levels in processed sewage, a challenge for many other sensing techniques. Security applications may include detection of explosives, and in healthcare MUP-based sensors may become important diagnostic tools.