Washington: A new type of bio-sensor can detect
minute traces of glucose in saliva, tears and urine, doing away
with pinpricks for diabetes testing.
"It's an inherently non-invasive way to estimate glucose content
in the body," said Jonathan Claussen, former Purdue University
doctoral student and now a research scientist at the US Naval
"Because it can detect glucose in the saliva and tears, it is a
platform that might eventually help to eliminate or reduce the
frequency of using pinpricks for diabetes testing," said Claussen,
the journal Advanced Functional Materials reports.
Claussen and Purdue doctoral student Anurag Kumar led the project,
working with Timothy Fisher, Purdue professor of mechanical
engineering; D. Marshall Porterfield, professor of agricultural
and biological engineering; and other researchers at the
university's Birck Nanotechnology Centre, according to a Naval Lab
"Most sensors typically measure glucose in blood," Claussen said.
"Many in the literature aren't able to detect glucose in tears and
the saliva. What's unique is that we can sense in all four
different human serums: the saliva, blood, tears and urine. And
that hasn't been shown before."
The sensor has three main parts: layers of nanosheets resembling
tiny rose petals made of a material called graphene, which is a
single-atom-thick film of carbon; platinum nanoparticles; and the
enzyme glucose oxidase.
Besides diabetes testing, the technology might be used for sensing
a variety of chemical compounds to test for other medical
"Because we used the enzyme glucose oxidase in this work, it's
geared for diabetes," Claussen said.
"But we could just swap out that enzyme with, for example,
glutemate oxidase, to measure the neurotransmitter glutamate to
test for Parkinson's and Alzheimer's, or ethanol oxidase to
monitor alcohol levels for a breathalyzer. It's very versatile,
fast and portable."
The technology is able to detect glucose in concentrations as low
as 0.3 micromolar, far more sensitive than other electrochemical
biosensors based on graphene or graphite, carbon nanotubes and
metallic nanoparticles, Claussen said.