Optical Polarimetry for Glucose Sensing

Background

Polarized light refers to light whose electric field oscillates in a particular way - examples include planer, elliptically, or circularly polarized light. The use of polarimetry for glucose detection has existed for several years primarily for use in the sugar industry.

The equation which describes the phenomenon of polarimetry is given by:

where [α] is the specific rotation at a given wavelength (λ), α is the observed rotation, C is the concentration of optically active sample, and L is the sample path length.

As can be seen from this equation, the concentration of the solute of interest is directly proportional to the observed rotation in polarization. Thus, the concentration of an optically active compound can be calculated if we can determine the observed rotation of polarization for the light beam passing through the sample.

In our research, we utilize this fundamental concept toward the development of a polarimetric system for noninvasive glucose detection in the human body.

Experimental Setup

The ability to monitor the low levels of glucose typical in the body (in vivo) using polarimetry requires very sensitive instrumentation. The pictures below illustrate the set up used in our laboratory for the in vitro experiments:

 

Experimental setup of the polarimetric system (1)

The in vitro experiments were primarily focused on glucose doped water solutions. Currently we are proceeding with in vivo studies employing rabbit model.

Setup of the in vivo experiments (2)

References:

(1) Malik, B., and Coté, G., “Real-time dual wavelength polarimetry for glucose sensing” Proc. SPIE, Vol. 7186, 718604 (2009).

(2) Cameron, B., “The Application of Polarized Light to Biomedical Diagnostics and Monitoring,” Ph.D. Dissertation, Texas A&M University, College Station, TX 77843, (2000).

 

For more information, contact Bilal Malik