Skeletal muscle death from the perspective of electrical impedance as evidenced by experiment and numerical modelling

Understanding the biophysical changes in skeletal muscle tissue during the minutes to hours post-excision or following irreversible damage is critical for biomedical applications and food processing. Muscle tissue, composed of myofibrillar and sarcoplasmic proteins, water, lipids, and connective tissue, forms a complex network of interactions that persists as it degrades post-mortem. This study investigates skeletal muscle death through ex vivo experimental measurements on porcine muscle, supported by a novel numerical model that builds the muscle up from individual fibres. Skeletal muscle tissue was found to exhibit strong anisotropy in electrical conductivity due to its structure. It demonstrates much lower conductivity perpendicular to muscle fibres compared to parallel with them owing to its limited plasma membrane conductivity. We explore how post-mortem changes, including increased membrane permeability during membrane decomposition, and external interventions like electroporation, alter these anisotropic properties. Our findings have implications for biomedicine, specifically treatments targeting muscle tissue, such as pulsed field ablation for cardiac arrhythmias, and characterisation of in-vitro engineered muscle tissues. In food production, the study informs applications of pulsed electric fields to modify meat structure and texture. By integrating experimental and theoretical approaches, this work provides new insights into the electrochemical and structural dynamics of skeletal muscle during and after death.