Electrospun fibrinogen–PLA nanofibres for vascular tissue engineering

Here we report on the development of a new type of hybrid fibrinogen–polylactic acid (FBG–PLA) nanofibres (NFs) with improved stiffness, combining the good mechanical properties of PLA with the excellent cell recognition properties of native FBG. We were particularly interested in the dorsal and ventral cell response to the nanofibres' organization (random or aligned), using human umbilical endothelial cells (HUVECs) as a model system. Upon ventral contact with random NFs, the cells developed a stellate-like morphology with multiple projections. The well-developed focal adhesion complexes suggested a successful cellular interaction. However, time-lapse analysis shows significantly lowered cell movements, resulting in the cells traversing a relatively short distance in multiple directions. Conversely, an elongated cell shape and significantly increased cell mobility were observed in aligned NFs. To follow the dorsal cell response, artificial wounds were created on confluent cell layers previously grown on glass slides and covered with either random or aligned NFs. Time-lapse analysis showed significantly faster wound coverage (within 12 h) of HUVECs on aligned samples vs. almost absent directional migration on random ones. However, nitric oxide (NO) release shows that endothelial cells possess lowered functionality on aligned NFs compared to random ones, where significantly higher NO production was found. Collectively, our studies show that randomly organized NFs could support the endothelization of implants while aligned NFs would rather direct cell locomotion for guided neovascularization.