Noninvasive Biosensor Could Eliminate Needles from Blood Glucose Monitoring

Developing an alternative approach to blood glucose monitoring that does not rely on lancets and pinpricks has been a primary goal of diabetes device R&D in recent years. Contributing to this effort, researchers at Purdue University have engineered a noninvasive, low-cost biosensor capable of detecting glucose in concentrations as low as 0.3 micromolar in blood, urine, saliva, and tears.

Although sensing devices have previously been developed that can measure glucose in blood, the Purdue biosensor is the first technology capable of detecting glucose in saliva, tears, and urine in addition to blood, according to the researchers. Such a unique platform, they state, holds promise for ultimately reducing or altogether eliminating the need for lancets and pinpricks in glucose monitoring.

An additional advantage of the biosensor is that it is relatively inexpensive to produce because it requires few processing steps. "Typically, when you want to make a nanostructured biosensor, you have to use a lot of processing steps before you reach the final biosensor product," says Purdue doctoral student Anurag Kumar. "That involves lithography, chemical processing, etching, and other steps. The good thing about these petals is that they can be grown on just about any surface, and we don't need to use any of these steps, so it could be ideal for commercialization."

The biosensor was constructed from layers of graphene nanosheets that resemble tiny rose petals, platinum nanoparticles, and the enzyme glucose oxidase. "Each petal contains a few layers of stacked graphene. The edges of the petals have dangling, incomplete chemical bonds, defects where platinum nanoparticles can attach. Electrodes are formed by combining the nanosheet petals and platinum nanoparticles. Then, the glucose oxidase attaches to the platinum nanoparticles. The enzyme converts glucose to peroxide, which generates a signal on the electrode," according to a university press release.

While initial development of the biosensor has focused on glucose monitoring, the biosensor could potentially be employed for other medical tests by simply swapping out the enzyme. Using glutemate oxidase in lieu of glucose oxidase, for example, could enable testing for such conditions as Parkinson's or Alzheimer's, the researchers note.