Glucose monitoring for diabetes made easy with a blood-less method

In their article titled "A plasmonic cuvette": dye chemistry coupled to plasmonic interferometry for glucose sensing in the journal Nanophotonics the research team led by Domenico Pacifici describes how a suitable mixture of enzymes can be employed to selectively generate a red fluorescent molecule. These can then be selectively optically detected in a complex environment full of a plethora of other substances such as human saliva. Tiny volumes of the compound are investigated by means of a nano-structured surface of silver and aluminum oxide. As a plasmonic interferometer this structure facilitates the interactions of light with the mixture under investigation. By measuring the absorption of light of a specific wavelength the concentration of glucose can be inferred.

Non-invasively studying saliva is made possible due to the high sensitivity of this method. Although a strict dependence between glucose concentrations in blood and saliva exist, the latter is smaller by a factor of hundred. Additionally only a tiny volume of material -- around the a quarter of the volume of a water droplet -- is required to achieve this.