Bioelectricity drives several processes in the human body. The development of new
materials that can deliver electrical stimuli is gaining increasing attention in the field of tissue
engineering. In this work, novel, highly electrically conductive nanofibers made of poly [2,20-
m-(phenylene)-5,50-bibenzimidazole] (PBI) have been manufactured by electrospinning and then
coated with cross-linked poly (3,4-ethylenedioxythiophene) doped with poly (styrene sulfonic acid)
(PEDOT:PSS) by spin coating or dip coating. These scaffolds have been characterized by scanning
electron microscopy (SEM) imaging and attenuated total reflectance Fourier-transform infrared
(ATR-FTIR) spectroscopy. The electrical conductivity was measured by the four-probe method at
values of 28.3 S
m^-1 for spin coated fibers and 147 S
m^-1 for dip coated samples, which correspond,
respectively, to an increase of about 105 and 106 times in relation to the electrical conductivity of
PBI fibers. Human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) cultured on the
produced scaffolds for one week showed high viability, typical morphology and proliferative capacity,
as demonstrated by calcein fluorescence staining, 40,6-diamidino-2-phenylindole (DAPI)/Phalloidin
staining and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] assay. Therefore,
all fiber samples demonstrated biocompatibility. Overall, our findings highlight the great potential of
PEDOT:PSS-coated PBI electrospun scaffolds for a wide variety of biomedical applications, including
their use as reliable in vitro models to study pathologies and the development of strategies for
the regeneration of electroactive tissues or in the design of new electrodes for in vivo electrical
stimulation protocols.