Electrophysiological microenvironment and site-specific cell behaviors regulated by fibrous aniline trimer-based polyurethanes in bone progressive regeneration

Inspired by the endogenous electric field of natural bone tissue, fibrous aniline trimer (AT)-based polyurethane (FPAT) membranes have been fabricated with good electroactivity through electrospinning, which may serve to restore electrophysiological microenvironment and regulate site-specific cell behaviors to promote osteogenesis. By virtue of the redox activity, the electroactive FPAT membranes exhibited the progressive scavenging ability of reactive oxygen species (ROS) with increasing AT content. Furthermore, a systematic study of specific bio-markers was practiced to draw a comprehensive understanding of the bioelectrical stimulation, including in vitro cell experiments, in vivo RNA-sequencing, subcutaneous implantation, and bone defect repair. Focused on site -specific cell behaviors, both macrophages and mesenchymal stem cells (MSCs)were significantly regulated by the AT-based membranes on electrophysiological microenvironment. For macrophages, the AT-based mem-branes polarized macrophages to M2 phenotype by efficiently clearing excessive ROS to manipulate the osteoimmune microenvironment in vitro and in vivo. For MSCs, the FPAT membranes scavenged excessive intracellular ROS and elevated intracellular Ca2+ concentration, thereby promoting cell proliferation and driving osteogenesis differentiation. Histology results and gene expression profiles on a rat calvarial bone defect model discovered the efficacy of the AT-based membranes in immunomodulation and osteogenesis. Moreover, the upregulated genes at the RNA level and signaling pathways testified that the electroactive FPAT membranes were strongly involved in regulating macrophage polarization and bone repairing process. This work demonstrated an efficacious therapy of electroactive FPAT membranes from the regulatory mechanism, cellular to tissue levels in bone progressive regeneration, which could provide a legible evaluation system for conductive materials.