“…In a more recent work, Colombo et al [9] validated their EChT in silico model with in vivo experiments and an in vitro model using a collagen gel with NaCl at physiological concentrations. They found that an initial condition with almost neutral pH evolves between electrodes into extreme cathodic alkaline and anodic acidic fronts moving towards each other, leaving the possible existence of a Avramov Ivic ´et al [10] introduced an in vitro EChT model consisting in an agar-agar gel with ionic content and a basic pH indicator (phenolphtaleine). They claim their in vitro model to be a better approximation for in silico model validation than previous aqueous solution models.…”