To minimize the pain and inconvenience of daily blood tests for diabetics, researchers lead by Ishan Barman at MIT’s Spectroscopy Laboratory, USA, are working on a noninvasive way to measure blood glucose levels using Raman spectroscopy.

One of the major obstacles they have faced is that near-infrared light penetrates only about half a millimeter below the skin, so it measures the amount of glucose in the interstitial fluid (ISF) around the skin cells, not the amount in the blood. To overcome this, the team came up with an algorithm that relates the two concentrations, and overcomes the physiological time lag between blood and ISF glucose levels after eating.

Called Dynamic Concentration Correction (DCC), the method is based on the mass transfer of glucose between blood and ISF. It has been tested with human volunteers to show that the predicted glucose concentrations closely match the measured glucose concentrations.

• Accurate Spectroscopic Calibration for Noninvasive Glucose Monitoring by Modeling the Physiological Glucose Dynamics
  I. Barman, C.-R. Kong, G. P. Singh, R. R. Dasari, M. S. Feld,
  Anal. Chem. 2010, 82 (14), 6104–6114.
  DOI: 10.1021/ac100810e