CC BY
18B-O-12
The phenomenon of electromechanical properties of cartilage tissue during cooling and heating from -10°C to 40°C
E. Kasianenko1, A. Omelchenko1
1Federal Scientific Research Centre "Crystallography and photonics" of Russian Academy of Sciences, Institute of Photon Technologies, Moscow, Russian Federation
Medical operation of laser-induced reshaping cartilage tissue allows achieving a stable form of cartilage. After bending of the form, mechanical stresses arise in the volume of the tissue, which relaxes after the laser impact due to the heating [1]. It is known that the mechanical properties of cartilage tissue are determined by the interaction of the charges of the matrix molecules [2, 3]. The reshaping of cartilage during laser heating is associated with a change in the matrix, as well as the possible transfer of its electrical charges and electrical conductivity of the tissue [4]. To ensure the effectiveness and safety, it is advisable to monitor the physical characteristics of the tissue, which affect the degree of exposure and the moment of switching off the laser.
The purpose of work was to study the kinetics of the activation energy of electric charges generation during repetitively pulsed laser heating of cartilage in a regime close to that used in medical technology. Relaxation of charges during tissue cooling to -10°C and subsequent generation by laser heating were controlled by measuring the electrical conductivity of the tissue.
Measurement of electrical conductivity with the help of direct current allows us to control the electrophysical properties of the tissue: the state of free charges, their mobility and concentration in the matrix. An analysis of the dependences of the conductivity of the articular cartilage and the dynamics of its heating on the time of laser heating showed the temperature dependence of the electrical conductivity of the tissue. The change in conductivity during cooling of cartilage to negative temperatures allowed to draw conclusions about the behaviour of the mobility of free charges in the cartilage matrix. The knowledge of the activation energy of the charge generation process makes it possible to determine and monitor the structural changes in cartilage during laser heating.
These results can be used as the basis for the control and diagnostic system for monitoring changes in the tissue state during laser-induced reshaping of cartilage implants.
The study was supported by the Russian Foundation for Basic Research (Project No. 18-2902124).
References
[1] Bagratashvili V.N., Sobol E.N., Shekhter A.B. Lasernaya engeneria khrashey. M. FizMatLit 2006 (in Russian).
[2] Omel'chenko A.I. (2009). Effect of repetitive laser pulses on the electrical conductivity of intervertebral disc tissue. Quantum Electronics, 39(3), 279
[3] Legare A., Garon M., Guardo R., Savard P., Poole A.R., Buschmann M.D. Detection and analysis of cartilage degeneration by spatially resolved streaming potentials. J Orthop Res 2002;20:819e26.
[4] Sobol E.N., Milner T.E., et al. Laser reshaping and regeneration of cartilage. Laser Phys. Lett. 2007, 4, No. 7, p. 488-502.
