Electreted Sandwich Membranes with Persistent Electrical Stimulation for Enhanced Bone Regeneration

Physiologically relevant electrical microenvironments play an indispensable role in manipulating bone metabolism. Although implanted biomaterials that simulate the electrical properties of natural tissues using conductive or piezoelectric materials have been introduced in the field of bone regeneration, the application of electret materials to provide stable and persistent electrical stimulation has rarely been studied in biomaterial design. In this study, a silicon dioxide electret-incorporated poly(dimethylsiloxane) (SiO2/PDMS) composite electroactive membrane was designed and fabricated to explore its bone regeneration efficacy. SiO2 electrets were homogeneously dispersed in the PDMS matrix, and sandwich-like composite membranes were fabricated using a facile layer-by-layer blade-coating method. Following the encapsulation, electret polarization was conducted to obtain the electreted composite membranes. The surface potential of the composite membrane could be adjusted to a bone-promotive biopotential by tuning the electret concentration, and the prepared membranes exhibited favorable electrical stability during an observation period of up to 42 days. In vitro biological experiments indicated that the electreted SiO2/PDMS membrane promoted cellular activity and osteogenic differentiation of mesenchymal stem cells. In vivo, the electreted composite membrane remarkably facilitated bone regeneration through persistent endogenous electrical stimulation. These findings suggest that the electreted sandwich-like membranes, which maintain a stable and physiological electrical microenvironment, are promising candidates for enhancing bone regeneration.