1. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Anisotropy of glucose diffusion in muscle tissue Alexey N. Bashkatov, Elina A. Genina, Marina D. Kozintseva, Valery V. Tuchin Department of Optics and Biophotonics of Saratov State University, Saratov, Russia Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia e-mail: a.n.bashkatov@mail.ru Alexey N. Bashkatov, Elina A. Genina, Marina D. Kozintseva, Valery V. Tuchin Department of Optics and Biophotonics of Saratov State University, Saratov, Russia Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia e-mail: a.n.bashkatov@mail.ru

2. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Motivation: For the last two decades the optical method as a tool for clinical functional imaging of physiological conditions, cancer diagnostics and therapies is of great interest due to its unique informative features, simplicity, safety and low cost in contrast to conventional X-ray computed tomography, magnetic resonance imaging and ultrasound. However, the main limitations of the optical imaging techniques are connected with strong light scattering in tissue. Optical clearing is perspective technique for solution of the problem. However, in spite of numerous investigations, optical clearing of muscle tissue has not be studied in detail. Goal of the study is to investigate optical clearing of muscle tissue For the last two decades the optical method as a tool for clinical functional imaging of physiological conditions, cancer diagnostics and therapies is of great interest due to its unique informative features, simplicity, safety and low cost in contrast to conventional X-ray computed tomography, magnetic resonance imaging and ultrasound. However, the main limitations of the optical imaging techniques are connected with strong light scattering in tissue. Optical clearing is perspective technique for solution of the problem. However, in spite of numerous investigations, optical clearing of muscle tissue has not be studied in detail. Goal of the study is to investigate optical clearing of muscle tissue

3. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Materials and Methods:  For this study twenty samples of bovine muscle tissue have been used. The samples have been separated on four groups: 1) five fresh samples longitudinal sectioned along collagen fibers 2) five frozen samples longitudinal sectioned along collagen fibers 3) five fresh samples randomly sectioned 4) five frozen samples randomly sectioned  Measurement of collimated transmittance have been performed using a commercially available spectrometer USB4000-Vis-NIR (Ocean Optics, USA) in the spectral range 400-1000 nm  All measurements were performed at room temperature (about 20°C)  Commercially available 40% aqueous solution of glucose was used  Refractive index of the solution is 1.391. It has been measured using Abbe refractometer at wavelength 589 nm  For this study twenty samples of bovine muscle tissue have been used. The samples have been separated on four groups: 1) five fresh samples longitudinal sectioned along collagen fibers 2) five frozen samples longitudinal sectioned along collagen fibers 3) five fresh samples randomly sectioned 4) five frozen samples randomly sectioned  Measurement of collimated transmittance have been performed using a commercially available spectrometer USB4000-Vis-NIR (Ocean Optics, USA) in the spectral range 400-1000 nm  All measurements were performed at room temperature (about 20°C)  Commercially available 40% aqueous solution of glucose was used  Refractive index of the solution is 1.391. It has been measured using Abbe refractometer at wavelength 589 nm

4. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Experimental setup The scheme of experimental setup for the measurements of collimated transmittance: 1 – halogen lamp (HL-2000), 2 – delivering optical fiber; 3 – tissue sample; 4 – object-plate; 5 – receiving optical fiber; 6 – multichannel spectrometer (USB4000-Vis-NIR); 7 – PC

5. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 The transmittance spectra of muscle measured concurrently with administration of glucose solution at different time intervals The time-dependent transmittance of muscle measured at different wavelength concurrently with administration of glucose solution Fresh muscle tissue longitudinally sectioned along collagen fibers

6. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 The transmittance spectra of muscle measured concurrently with administration of glucose solution at different time intervals The time-dependent transmittance of muscle measured at different wavelength concurrently with administration of glucose solution Frozen muscle tissue longitudinally sectioned along collagen fibers

7. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 The transmittance spectra of muscle measured concurrently with administration of glucose solution at different time intervals The time-dependent transmittance of muscle measured at different wavelength concurrently with administration of glucose solution Fresh muscle tissue randomly sectioned

8. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 The transmittance spectra of muscle measured concurrently with administration of glucose solution at different time intervals The time-dependent transmittance of muscle measured at different wavelength concurrently with administration of glucose solution Frozen muscle tissue randomly sectioned

9. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Glucose diffusion coefficient estimation For measurement of glucose diffusion coefficient we used the following simple approach suggested by Oliveira et al. (Oliveira L.M., et al, Laser Physics, Vol. 23(7), 075606, 2013) The diffusion is characterized by Fick’s law: In a first-order approximation, solution of the diffusion equation has the form: The collimated transmittance can be described by the equation: The diffusion coefficient of PEG-200 in skin can be calculated as:

10. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Glucose diffusion coefficient estimation longitudinally sectioned along collagen fibers randomly sectioned Fresh samples 6.021×10 -6 cm 2 /sec 5.361×10 -6 cm 2 /sec Frozen samples 1.066×10 -5 cm 2 /sec 8.391×10 -6 cm 2 /sec

11. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015

12. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 The normalized to initial values volume, thickness and weight of muscle measured concurrently with administration of glucose solution at different time intervals Volume and weight measurements

13. Saratov State University ______________________________________________ Department of Optics & Biophotonics __________________________________________________ Saratov Fall Meeting 2015 Acknowledgement: Grant of Russian Scientific Foundation № 14-15- 00186 Foundation namely D.I. Mendeleev of Tomsk State University Grant of President of Russian Federation «Leading Scientific School» № НШ-703.2014.2.