Assessment of tissue optical clearing as a function of glucose concentration using optical coherence tomography

In imaging of turbid biological samples using optical techniques, optical clearing methods can compensate for the lack of light penetration due to strong attenuation. The addition of optical clearing agents into scattering media increases the optical homogeneity of the sample and reduces its turbidity, allowing for the increased light penetration. In this study we investigated the extent of optical clearing in porcine skin by utilizing various concentrations of glucose solution. A goldplated mirror was fixed beneath the tissue and percentage clearing was determined by measuring the change in intensity of optical coherence tomography light returning from the mirror over time. A ratio of percentage clearing per tissue thickness for 10%, 30%, and 50% glucose was determined to be to be (4.7 ± 1.6%) mm^-1 (n = 6), (10.6 ± 2.0%) mm^-1 (n = 7), and (21.8 ± 2.2%) mm^-1 (n = 5), respectively. Although the extent of optical clearing in porcine skin was more significant for 50% glucose, the osmotic stress on the sample can cause considerable morphology change, thus a suitable concentration must be chosen for particular circumstances.