We have very little idea how well our body is doing on the inside – and particularly whether our brain is out of whack or our hormones unsettled. Personalised medicine offers the vision to track our health, but is currently limited to simple things like heart rate. What we really need is access to some of the important molecules circulating inside us, but so far this is too expensive to do in the home.

Our intelligent toilet exhibit showcases a new way we can access this by checking crucial molecules of interest that flow out in our urine. Since these are only molecules only exist in tiny quantities, they first have to be sifted out and then ‘rattled’ with a laser. This is called Raman spectroscopy and measures the target molecules in a similar way to how you may shake a wrapped present to guess what is within. To achieve this, we use a sieve of barrel-shaped molecules just big enough to trap single target molecules inside. The sticky lids on these barrels can suck nano-sized balls of gold onto either end, which traps light into the tiny nano-gap where the barrel holds its load. The scattered laser photons from these gaps have signature colours depending on which molecules were sifted out of the urine. One current application for the system is towards better treatment of patients who suffer from depression, as no method exists to accurately determine the dosage of medication required. However, this could also be extended to other disorders and, possibly, drug testing.

The Intelligent Toilet demo at the Royal Society Summer Exhibition reveals the toilet’s inner workings. The flow of lights depicts urine’s path through to the assembly of gold nano-particles, which trap target molecules of interest. The Illumination of gold nanoparticles shows the capture of the vibrational (Raman) signals used to identify the concentrations of neurotransmitters like dopamine or other molecules. Displays on either side of the toilet will be screening our informative animation showing you how this technology works – this animation can also be viewed below. We invite you to actively become part of our research by telling us how you feel about the privacy of your biomedical information produced from this intriguing technology – complete our short ethical survey to guide us!

The Intelligent Toilet brings together research and concepts from the NanoPhotonics Centre and the Melville Laboratory for Polymer Synthesis ().

The physical toilet used in our demo was supplied by our sponsor TOTO.

Technical Notes:

Learn more about the laser ‘rattling’ – or Raman spectroscopy – in these publications from the University of Cambridge

1) Quantitative multiplexing with nano-self-assemblies in SERS, Scientific Reports 4, 6785 (2014); DOI: 10.1038/srep06785

2) Observing Single Molecules Complexing with CB[7] by SERS, J.Phys.Chem.Lett.7, 704 (2016); DOI 10.1021/acs.jpclett.5b02535

3) In-situ SERS monitoring of photochemistry within a nano-junction reactor, Nano Lett 13, 5985 (2013); DOI 10.1021/nl403164c