Imaging of the interaction of low-frequency electric fields with biological tissues by optical coherence tomography

Low-frequency electric fields propagating in ex vivo biological tissues have been observed by using double-correlation optical coherence tomography (OCT). An adaptive Wiener filtering approach has been used to remove background noise, and a Fourier domain correlation algorithm has been applied to the sequence of OCT images. The results present the first direct observation (to our knowledge) of the scope of the electric field influencing biological tissues with OCT. The results show that variation in voltage and frequency of the applied electric field relates exponentially to the magnitude of its influence on biological tissue. The magnitude of influence is about twice more for fresh tissue samples in comparison to nonfresh ones. The obtained results suggest that OCT can be used for observation and quantitative evaluation of the electrokinetic changes in biological tissues under different physiological conditions, functional electrical stimulation, and food quality control.