Protein found in mouse urine offers powerful biosensor

May be we cannot invent a better mouse trap, but we can still build better — and very useful — things relying on the humble mouse. In evidence: European research group has discovered that proteins found in mouse urine could help create powerful biosensors for environmental monitoring and security applications. According to researchers from Manchester University, the University of Pavia in Italy, and Sweden-based KTH and Linköping University, mouse major urinary proteins (MUPs) coated on a standard piezoelectric crystal enabled a one thousand-fold increase in sensor sensitivity compared with existing electronic sensing methods. The new biosensor could allow in situ monitoring of river water, which is currently tested manually in a laboratory. The four organizations carried out the research as part of the EU-funded General Olfaction and Sensing Projects on a European Level (GOSPEL) research network.

“We started to look at biological olfaction to see what we can learn from nature, not only in terms of absolute sensitivity and selectivity to single compounds, where natural systems are still perhaps six orders of magnitude ahead of what technological systems can do, but also what we can learn about how nature distinguishes single species [of odorant gas molecules] from very complex mixtures which might be dominated by another gas species,” said Rebecca Simpson, director of AO Action, a GOSPEL spin-out. “For the single species, current technology is in the range of parts per million [PPM] and we have been able to reach parts per billion with the mouse urine.” PPM refers to the number of odorant molecules in a million of every other molecule in a sample. MUPs are part of a protein family with a stable, cage-like structure that traps odorant molecules and then releases them slowly. This is what mice use to mark their territory, and is also what inspired the artificial olfaction researchers to explore other uses of MUPs, using a synthetic version of mouse urine in the experiments. According to the scientists, mice secrete a relatively large amount of protein — up to 40 mg per millilitre. “Other types of urine can also be used, but mice are particularly accessible and there is quite a lot already known about their urine,” said Simpson. “But these proteins exist in most animals, not just mammals. insects have them too, where they are no urinary proteins. They are part of a bigger class of proteins