Daily finger-prick blood tests are an uncomfortable fact of life for diabetics, but they may not always have to be. Scientists from Canada and the US have now developed a prototype home-use device that measures glucose levels in saliva samples.
It was already known that concentrations of glucose (and certain other biomarker chemicals) in a person's saliva are proportional to those in their bloodstream. Because glucose levels are much lower in saliva, however, specialized lab-based equipment is required to accurately measure them.
Researchers from the Université de Sherbrooke in Quebec and the Colgate-Palmolive Company in New Jersey set out to change that, by looking to an existing tool known as an electrochemical aptamer-based (E-AB) biosensor.
Such devices incorporate a specially engineered piece of DNA – called an aptamer – that binds to a target biomarker in a sample. When that happens, the sensor produces a measurable electrochemical signal.
Ordinarily, the aptamers used in E-AB biosensors aren't sensitive enough to reliably detect glucose in saliva. In order to change that, U Sherbrooke's Asst. Prof. Philippe Dauphin-Ducharme and colleagues boosted the sensitivity of aptamers that had already proven successful at measuring glucose levels in blood.
Those re-engineered aptamers were then mounted on a gold electrode within an E-AB biosensor, which was subsequently immersed in saliva gathered from a group of test subjects. Not only was the sensor able to measure glucose concentrations in the liquid – providing readings in just 30 seconds – it also retained its sensitivity for up to one week, as long as it was washed and stored in phosphate-buffered saline solution after each use.
That said, more research still needs to be conducted before the pricking of fingers becomes a thing of the past.
"At this stage, our study has only demonstrated that E-AB sensors are functional to measure salivary molecules," Dauphin-Ducharme told us. "To be able to be used in place of finger-pricks for diabetics, the sensor's utility must be further investigated and validated. To obtain this, we should examine whether the sensor response to salivary glucose correlates with the blood glucose levels in diabetics."
The technology could also be used to detect other biomarkers, using different aptamers. In fact, the scientists created an alternate version of the device that accurately measured saliva levels of AMP (adenosine monophosphate), which is a biomarker associated with gum disease.
The study is described in a paper that was recently published in the journal ACS Sensors.
Source: American Chemical Society
