Minimally invasive glucometer using the magneto-optical rotatory effect (MORE)

Diabetes mellitus is the most common disorder of the endocrine system and affects nearly 16 million people in the United States and over 100 million people worldwide. However, all existing conventional methods of home blood glucose monitoring require obtaining a blood sample by pricking the fingertip with a needle or lancet and then using paper strips that change color as soon as exposed to a drop of the blood sample to indicate glucose levels. ^ Diabetic patients are generally recommended to check their blood glucose level 5 to 7 times per day. Since these blood glucose tests are painful, intimidating, laborious, and expensive, they strongly discourage patient compliance. Thus it is necessary to develop a non-invasive blood glucose method which could provide fast, painless, and convenient glucose monitoring to diabetic patients. ^ The study presented here introduces and provides basic scientific and engineering data on a new approach using the Faraday effect of glucose solutions themselves. We call this effect the Magneto Optical Rotatory Effect of glucose or MORE to distinguish it from other applications of the Faraday effect that are used to create closed and open loop polarimetry systems. The “MORE” effect results from nonlinear mixing of conventional optical rotation with Faraday rotation, creating a signal at the Faraday modulator frequency that is indicative of the glucose concentration in the solution. ^ The method to demonstrate MORE signals in the presence of enucleated goats eyes also will be discussed in this study. As far as we are aware, this is the first time that this type of magnetic rotatory effect of glucose solutions has been proposed or investigated for minimally invasive glucometry, and demonstrated in ex vivo living tissue. ^ The optical glucose sensing technique using the magnetic optical rotatory effect of glucose has many advantages over currently existing invasive and non-invasive methods, since the method is based on shining a brief pulse of light into the front of the eye. A highly coherent light source, accurate optical components, and a sophisticated analyzing system are employed in this study. The optical glucose sensing method introduced in this study can be miniaturized using current integrated optics, optoelectronics, and semiconductor technology and has the potential to provide a low cost, fast, and compact non-invasive glucose sensor for the diabetic patient within the near future.