Making Sense of Electrical Stimulation: A Meta-analysis for Wound Healing

Abstract

Electrical stimulation as a mode of external enhancement factor in wound healing has been explored widely. It has proven to have multidimensional effects in wound healing including antibacterial, galvanotaxis, growth factor secretion, proliferation, transdifferentiation, angiogenesis, etc. Despite such vast exploration, this modality has not yet been established as an accepted method for treatment. This article reviews and analyzes the approaches of using electrical stimulation to modulate wound healing and discusses the incoherence in approaches towards reporting the effect of stimulation on the healing process. The analysis starts by discussing various processes adapted in in vitro, in vivo, and clinical practices. Later it is focused on in vitro approaches directed to various stages of wound healing. Based on the analysis, a protocol is put forward for reporting in vitro works in such a way that the outcomes of the experiment are replicable and scalable in other setups. This work proposes a ground of unification for all the in vitro approaches in a more sensible manner, which can be further explored for translating in vitro approaches to complex tissue stimulation to establish electrical stimulation as a controlled clinical method for modulating wound healing.

Keywords: Current of injury; Electro-modulation; Electrodes; Impedivity; Skin wounds; Stimulation protocol; Trans-epithelial potential; Wound healing.

Fig. 1

Schematic anatomy of skin wound showing different tissue layers

Fig. 2

Comparison between acute and chronic wound healing [8, 10]

Fig. 3

Inflammatory stage of wound healing

Fig. 4

Proliferative stage of wound healing

Fig. 5

Remodeling stage of wound healing

Fig. 6

Trans-epithelial potential (TEP) and current of injury: intact skin vs. wound site

Fig. 7

Electrode configurations. a Bipolar configuration with electrodes on both sides of the wound. b Bipolar configuration with one electrode on the wound. c Tripolar configuration. d Tetrapolar configuration

Fig. 8

Conduction pathways through sample (top view)

Fig. 9

Conduction pathways through sample (side view)