Monitoring of Glucose Diffusion in Epithelial Tissues with Optical Coherence Tomography

Biomedical Engineering Program, University of Houston, Houston, TX 77204, USA;

Institute of Optics and Biophotonics, Saratov State University, Saratov, 410012, Rus-

sia

Valery V. Tuchin

Institute of Optics and Biophotonics, Saratov State University, Saratov, 410012, Rus-

sia;

Institute of Precise Mechanics and Control of RAS, Saratov 410028, Russia

20.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624

20.2 Basic Theories of Glucose-Induced Changes of Tissue Optical Properties . . 627

20.3 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646

Functional imaging, monitoring, and quantification of glucose diffusion in epithelial

and underlying stromal tissues in vivo as well as controlling of tissue’s optical prop-

erties are extremely important for many biomedical applications including develop-

ment of noninvasive or minimally-invasive glucose sensors as well as for therapy and

diagnostics of various diseases, such as cancer, diabetic retinopathy, and glaucoma.

In order to obtain clinically acceptable accuracy and sensitivity of a noninvasive glu-

cose biosensor, physiology and kinetics of glucose diffusion in tissues should be

assessed in vivo. Difference in glucose diffusion rates in healthy and diseased tis-

sues could potentially be used for development of novel early diagnostic methods.

Furthermore, the selective translucence of the upper tissue layers is a key technique

for structural and functional imaging, particular for detecting of local static or dy-

namic inhomogeneities hidden by a highly scattering medium. In this Chapter we

describe recent progress made on developing of a noninvasive molecular diffusion

biosensor based on Optical Coherence Tomography (OCT) technique. The diffusion

of glucose and other macromolecules was monitored and quantified in several ep-

ithelial tissues both in vitro and in vivo. Due to capability of the OCT technique for

depth-resolved imaging of tissues with high in-depth resolution, the molecular diffu-

sion could be quantified not only as a function of time but also as a function of depth.