Electrochemical sensing of cell viability: A scalable platform from 2D monolayers to 3D tissue models.

The trend toward animal-free testing in toxicology and drug development has accelerated the adoption of complex 3D in vitro models. However, standard colorimetric viability assays suffer from severe limitations due to chemical interferences. To address these challenges, we designed a versatile sensor platform based on screen-printed carbon electrodes to overcome optical bottlenecks by quantifying cell viability through the electrochemical reduction of MTS-formazan. The electrochemical sensor was validated in 2D human dermal fibroblasts and keratinocytes at different cell confluences. Importantly, it successfully assessed viability in both 2D cell monolayer cultures and reconstructed human epidermis exposed to an OECD-panel of irritant and non-irritant chemicals. The electrochemical approach provides a technologically robust and interference-free tool that enhances reliability in viability assays, overcoming the traditional limitations of colorimetric measurements. This methodology represents a transversal tool applicable to any tissue offering a robust and promising solution for high-throughput screening in pharmacology, cosmetics, and biomedical research.