Smart pH-Responsive Conductive Polyurethane Fibers: Doping Strategies for Advanced Wound Care

Inspired by the pH fluctuations of skin wounds, a protonic acid-doped conductive polyurethane (dCP) fibrous membrane was developed via electrospinning. This study introduces a smart conductive system with pH-responsive electroactivity that adapts to the dynamic wound microenvironment, enhancing both wound healing and antibacterial efficacy. Systematic optimization with camphorsulfonic acid (CSA) doping, the system was evaluated under three physiological pH conditions (7.4, 6.7, and 7.9), representing different healing stages. FTIR spectroscopy, cyclic voltammetry, and conductivity measurements confirmed that dynamic electroactivity and pH-responsive behavior originate from protonation/deprotonation-mediated interactions between conductive components and microenvironmental pH. The CSA-doped membranes exhibit stable conductivity (4.72-9.48 × 10^-4 S/cm) and strong antibacterial activity (>98% efficacy against <i>Staphylococcus aureus</i>, per ISO standards) under various pH levels, with conductivity values approaching those of native skin. Under alkaline condition (pH 7.9), the CSA-doped membranes achieve higher sensitivity and conductivity, showing 1.32-fold and 1.13-fold increases compared to neutral (pH 7.4) and acidic (pH 6.7), respectively. At pH 6.7, the dCP membrane significantly promotes M1-to-M2 macrophage polarization in vitro, confirmed by CD206/iNOS immunofluorescence staining and quantitative RT-PCR analysis. In wound treatment applications, the pH-adaptive dCP dressings synergistically improve inflammation suppression, angiogenesis, nerve regeneration, and collagen remodeling while minimizing scar formation, as evidenced by histological and immunohistochemical analyses (H&E, Masson's trichrome, VEGF, NGF, and TGF-β) in a rat model. This pH-adaptive CSA-doped conductive dressing design offers a self-regulating, multitasking strategy for advanced wound healing, effectively addressing the limitations of traditional static dressings.