John Patrick-Thomas

This article was taken from the March 2014 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.

Advances in genomics are moving the bioengineering laboratory into the city sewers. In 2014, our wastewater systems will become smart, with automated sampling and lab-on-a-chip biosensors enabling the real-time prediction of viral outbreaks, making connections between environmental factors and public health, and answering fundamental questions about the nature of cities. This digital nervous system for the sewers will be a scaled-up version of the human enteric nervous system -- a major component of our nervous system, which carries information between gut and brain.


Compared to about ten trillion human cells, there are about 90 trillion cells in our body that are not actually "us"; and the majority reside in the gut. The Human Microbiome Project's researchers showed these microbes collectively contain well over 100 times more genes than our own genome, and these contribute significantly to our health and well-being. In the gastrointestinal tract, for example, bacteria can provide essential nutrients and help us digest foods that we otherwise could not absorb. But they can also metabolise drugs we take, lowering their efficacy or even creating toxic byproducts. Microbiome function is believed to be so essential and pervasive that many have recently referred to it as "the invisible organ".

Advances in DNA-sequencing tech make it possible to characterise the human microbiome, and soon we will be monitoring it daily, looking out for warnings of illness. At MIT's SENSEeable City Lab, we are working towards the concept of the smart toilet. This would recognise its user and carry out biomarker and microbiota analysis.

The Japanese bathroom maker Toto has already developed an early version of a toilet that can carry out (simpler) urine analysis, and advances in lab-on-a-chip tech promise to broaden the spectrum of at-home molecular analysis in the near future. The key challenges to a comprehensive scan remain the size, cost and complexity of the technology needed to move sequencing and bioassays out of the lab.


Individual sensors such as these are more than a year off, but similar sensing can be done sooner at city scale. A vast reservoir of valuable information on human health and behaviour lives in our sewage, but the majority of this resource remains untapped by current research and available technologies. This is the goal of a smart sewage system called Underworlds, developed at MIT by the SENSE-able City Lab and the Alm Lab. Examining aggregated wastewater across several cities, in 2014 the project will establish the techniques and technologies required to deploy a near-real-time network of biosensors, automata and purpose-built labs. The team is prototyping all components of the future smart grid, from the physical infrastructure required across a city, through the biological assays and downstream analytics and visualisation tools to make the most out of the collected data.

Underworlds promises to decode the biological signature of cities, providing information that can extend the boundaries of epidemiological science and understanding, enable real-time public-health strategies and inform policy makers and researchers with an open, cross-disciplinary data platform for studying urban health. Extending the digital nervous system of our environments to the depths of the urban underworld will tell the connected story of the world living inside us and the world we live in.

Carlo Ratti is the director and Yaniv Jacob Turgeman is the head of research of the MIT SENSEable City Lab. Eric Alm is an associate professor in MIT's department of biological engineering