Investigating the Effect of Polypyrrole–Gelatin/Silk Fibroin Hydrogel Mediated Pulsed Electrical Stimulation for Skin Regeneration

In clinical practice to treat complex injuries, the application of electrical stimulation (ES) directly to the skin complicates the wound. In this work, the effect of a conductive hydrogel mediated electric field on skin regeneration is investigated. Polypyrrole incorporated matrices of gelatin and silk fibroin were prepared by two-step interfacial polymerization. The maximum electrical conductivity of 10 –4 S cm –1 was achieved when 200 mM polypyrrole was loaded. Mechanically stable and cytocompatible hydrogels were evidenced to have antioxidant and blood compatible characteristics. Human dermal fibroblast cells responded to pulsed stimulation of 100 or 300 mV mm –1 as observed from the increased expressions of TGFβ1, αSMA, and COLIAI genes. Further, the increase in the αSMA protein expression with the magnitude of electrical stimulation also suggested transdifferentiation of the fibroblast to myofibroblast. Moreover, Raman spectroscopy identified two fingerprint regions (collagen and lipid) to differentiate ES treated and nontreated samples. Therefore, the combination of hydrogels and electrical stimulation has potential therapeutic effects for accelerating the rate of skin regeneration.