‘Electronic nose’ could help to identify infant bowel condition

Researchers are developing an ‘electronic nose’ that can detect small quantities of gas in infants’ faeces, signalling a deadly bowel condition.

The project is a collaborative effort by clinicians and electronics experts at the University of West England (UWE) in Bristol and at NHS trusts in Bristol and Birmingham, with funding from Action Medical Research.

Necrotising enterocolitis (NEC) is a serious bowel condition that affects around 3,000 (mostly premature) babies each year. Up to 35 per cent of these babies die, while survivors often develop long-term health problems.

‘Doctors and nurses must be constantly on the lookout for symptoms of NEC, as premature babies in neonatal units can develop the disease at any time, with little or no warning. No current test can reliably identify babies in the early stages of the disease,’ said project co-ordinator Dr Alexandra Dedman from Action Medical Research.

Noting that some nurses claim to be able to pick up a characteristic smell in the faeces, the team set to work on a sensor that might be able to detect tell-tale gaseous molecules.

As Prof Norman Ratcliffe of UWE explained to the The Engineer, the researchers developed what they refer to as an ‘electronic nose’ based on modified heated metal oxide sensor technology.

Here, transition metal oxides are vacuum deposited onto a silica chip alongside a platinum heating element, which is used to regulate the sensor temperature — as the finished sensors exhibit different gas response characteristics at different temperature ranges.

In the presence of gas, the metal oxide causes the gas to dissociate into charged ions, resulting in changes in the conductivity measured as a signal.

‘The idea is that it will be in the ward or adjacent to the ward so it really will be a point-of care device — and we’ve got pattern recognition software for identifying Clostridium difficile and lots of other bacteria and viruses in the poo,’ said Ratcliffe.

’It’s sort of platform technology — we’re using the same system for urine and we’re getting very good initial results for diagnosing urinary tract infections and, more particularly, prostate cancer.’

Now the sensor has been developed, the research team will collect thousands of samples from infants to build a database of gaseous signatures before it can be deployed on wards.