‘Seeing’ disease with an optical filter sniff-cam
A newly developed ‘sniff-cam’ offers a potential way to ‘see’ common diseases using optical filters and RGB imaging.
Fibre optic biochemical gas sensor camera
The miniature camera functions as a fibre optic biochemical gas sensor, with a construction that emits UV light and detects the fluorescence it receives back from gaseous samples.
In particular, the probe includes a ring-type UV LED to supply the excitation light source, placed around a camera lens.
This allows excitation and imaging of the sample fluorescence to take place simultaneously.
Detecting diabetes, Parkinsons and cancer
The researchers from Tokyo Medical and Dental University applied this probe to samples of breath in order to measure gaseous ethanol in participants who had not consumed alcohol.
Ethanol is not only present in the breath of people who have been drinking, but is also among the volatile organic compounds produced by bacteria in the mouth and gut.
Such VOCs have been linked with common medical conditions, such as diabetes, cancer and Parkinson’s disease.
How does the sniff-cam work?
In their sniff-cam, the researchers used a catalyst, a nicotinamide adenine dinucleotide-dependent alcohol dehydrogenase to catalyse the redox reaction between gaseous ethanol and the oxidised form of nicotinamide adenine dinucleotide, or NAD.
Through this they produced NADH with an excitation wavelength of 340 nm and a fluorescence emission wavelength of 490 nm, both around the violet end of the visible light spectrum.
Measuring the distribution of light intensity from the fluorescence proved an effective and highly accurate way to determine the presence of gaseous ethanol in the sample.
“The new sniff-cam showed a 25-fold greater sensitivity and broader dynamic range (20.6 – 300,000 parts per billion) in comparison to those of the previously fabricated sniff-cam,” they wrote in the journal Analytical Chemistry.
Using the device, the team were able to determine that without alcohol consumption, breath typically contains around 116 ppb of gaseous ethanol, with a distribution of about 36 ppb in either direction.
The device offers significant potential for the use of optical filters and visual imaging when analysing breath samples for VOCs like gaseous ethanol.
As well as potentially indicating if the individual has been drinking, there are great possibilities for the early diagnosis of conditions associated with increased VOCs, like cancer, diabetes and Parkinson’s.