Advances in electroactive materials-based strategies for promoting skin wound healing

The loss of homeostasis of the local microenvironment is one of the processes encountered in chronic wound repair and is therefore a big challenge in clinical practice. Endogenous electric fields, being important biophysical cues in the wound bed, guide the direction of movement of the reparative cells, control the inflammatory process and help in the regeneration of the tissues. The classical external electrical stimulation equipment is strongly limited in the portability that can be offered and in the biocompatibility that can be ensured, which limits the wider clinical application of electroceutical approaches for wound care. Some recent developments in the field of electroactive materials give new methodologies for wound therapy by using electrical stimulation. In this article, first, the physiological process of wound closure and the origin and the properties of the endogenous electric fields are summarized. Then, it concentrates on three types of electroactive materials: conductive hydrogels that allow the effective conduction and enhancement of electrical signals through flexible interfaces; self-powered materials that generate their own power, e.g., by means of piezoelectricity or triboelectricity, transforming ambient mechanical energy into therapeutic electrical fields; and multifunctional composite materials that combine electrical stimulation together with antibacterial, exudate control, regulated drug delivery and immunomodulatory functions in a single system. Then the review explains in an ordered fashion the different mechanisms how the electric field can help wound repair, from the generation of directional signaling cues to the modulation of the inflammatory, proliferative and remodeling stages and also to the antimicrobial actions. Finally, it discusses existing barriers, i.e., the conflict between standard and personalized electrical stimulation parameters, the lack of long-term durability assessments and comprehensive biosafety evaluations. The review ends with some outlooks on the progress of future integrated closed-loop intelligent repair systems with sensing, decision-making and responsive functionalities.