The Bionic Interface: Considering the Material Mediated Electrical Stimulation of Stem Cells.

Electromaterials, in the field of tissue engineering, are designed to use an electrical signal to induce specific biological responses in cells and tissues. Using materials to control stem cell fate is a substantial field of research within tissue engineering, where stem cell differentiation is controlled through careful design of the material properties (roughness, topography, stiffness, and surface chemistry); the introduction of electromaterials into this field has added an extra dimensionality along with the ability to provide dynamic, temporally controlled cues through electrical stimulation. While significant research has focused on the cell-material interface for electrical stimulation platforms, the underlying reasons why certain materials outperform others remain poorly understood. Most existing studies emphasise mechanical stiffness and chemical composition, often overlooking the role of electronic charge transport. In this perspective, the focus is shifted to the charge transport properties of commonly used electrically conductive materials-such as metal-based electrode, carbon-based composites, and conjugated polymers-and discusses how these mechanisms modulate cellular responses. It is proposed that a deeper understanding of how materials inject, store, and redistribute charge at the interface can offer a new paradigm in designing electrically active scaffolds for more predictable and effective stem cell modulation.