By K.S. Jayaraman, IANS
Bangalore : Scientists in Kolkata have developed an inexpensive bloodless test for diabetes patients that requires just a sample of air breathed out by the patient.
Instead of rolling up the sleeve for a needle jab to draw blood, the patient will simply have to take a deep breath and blow it out onto a device no bigger than a fingernail.
“It is the need of the hour to develop a simple non-invasive diagnostic procedure which would revolutionize diabetes management,” Amarnath Sen, of the Central Glass and Ceramic Research Institute (CGCRI) in Kolkata who led the research team, told IANS.
Sen, who led a team of scientists from CGCRI and the Institute of Child Health (ICH) – also in Kolkata, believes the diabetes test kit, when fully developed and validated, should cost between Rs.500-700. It will require no consumables and last for five years.
The expensive ‘glucometers’ currently available in the market come with equally expensive test strips that must be thrown away after single use.
The scientific basis of Sen’s non-invasive test is the well known fact that the breath of a diabetic patient has a sweet, fruity smell.
The sweet odour comes from a chemical compound called acetone formed as a byproduct when the body converts fat into energy – a process called ‘ketosis’.
Ketosis takes place in all humans but the concentration of acetone in the breath of healthy individuals does not exceed 0.9 parts per million (ppm), Sen said.
However, in a diabetic – because glucose is not readily available as an energy source – the patient will be burning a lot of fat thereby pumping acetone in excess of normal levels.
The ‘sensor’ developed by Sen’s team measures the amount of acetone in the patient’s breath and thereby gives an indication of the diabetes status.
The importance of acetone in the breath as a ‘biomarker’ of diabetes is well known, and some methods have already been proposed by researchers elsewhere to measure it.
But these methods are unsuitable for routine diabetes tests because they are expensive, need bulky instrumentation and skilled operators, Sen said.
Another problem is these methods cannot detect very small amounts of acetone in the breath as there are more than 200 volatile organic compounds normally present.
The Kolkata team claims to have overcome this problem by fabricating an acetone sensor out of nano particles of gamma ferric oxide, a semi conducting material, that they produced using a specialized technique called ‘sonochemical method’.
Chemical reaction of this material with acetone alters the resistance of the sensor, producing an electrical signal whose strength is proportional to the amount of acetone present.
The sensor selectively detects even small amounts of acetone in the presence of other chemicals in human breath, the researchers claimed.
Sen said the sensor can detect acetone concentration from below the borderline concentration of diabetes detection (0.9 ppm) to higher concentrations. “This is one of the strong positive aspects of our sensor.”
The sensor needs detailed testing on healthy and diabetic patients under different conditions, Sen said. “Hence, it will take at least a couple of years before it gets into the market.”
The report by Sen and co-workers – Shirshendu Chakraborty and Indrani Ray – from CGCRI and Dibyajyoti Banerjee from ICH – appears in the Jan 25 issue of Current Science journal published by the Indian Academy of Sciences in Bangalore.
Commenting on the work, Muthuswamy Balasubramanyam, assistant director of the Madras Diabetes Research Foundation in Chennai, said that “non-invasive techniques are always better” and that the team’s work is an “important contribution”.
However, he said: “It is too early to predict” whether the new device would meet the requirements of accuracy and sensitivity. It would be “more important and interesting” to see whether it could pick up pre-diabetic individuals, Balasubramanyam told IANS.