A bioinspired nitric oxide sensor for asthmatics

To understand how I have used my Churchill Fellowship, it will be helpful to understand some of the more technical aspects about the nitric oxide sensor that I have developed. Firstly, the sensor is “bio-inspired” this mean we draw on the knowledge of naturally occurring systems and seek to incorporate those lessons into our sensors. The sensor I have developed is inspired by a haem protein which senses nitric oxide and leads to blood vessel dilation in our bodies.  The best known haem protein is haemoglobin which is found in our blood and transports oxygen to our tissues. Intriguingly, there are many other haem proteins found in nature, some of which do not bind oxygen (O₂) at all but are able to detect and respond to nitric oxide (NO) a very similar diatomic gas.

The unique thing about our sensor is that it uses a silk protein from honeybees. Honeybee silk is very different from the better known silks such as spider silk and silk worm silk. Dr Tara Sutherland at CSIRO has been exploring these silks for biomedical applications. Our approach is to the silk as the protein scaffold, thereby wraping the haem group within as silken coat. The silk both stabilises the haem centre but also can crucially control it’s reactivity as well. You normally think of silk as fibres, however we can make our silk proteins into a range of other material formats such as films and sponges. It is the transparent, malleable films which have proved to be the best suited for biosensors.

The final point about the sensor is that it is an electrochemical sensor in which nitric oxide binding to the protein is measured electrochemically. This is a similar concept to that used in the best known biosensor – the glucose monitor which has revolutionised the lives of diabetics.

In my fellowship I have been afforded the opportunity to deepen my knowledge of bioinorganic chemistry (the study of metals in proteins), I have been able to connect with some of the leading silk groups in the world to share our ideas with them and to work with a leading synthetic chemist to develop new metal centres to incorporate into my nitric oxide sensors.