Functionally graded membrane deposited with PDLLA nanofibers encapsulating doxycycline and enamel matrix derivatives-loaded chitosan nanospheres for alveolar ridge regeneration.

Functionally graded membranes (FGM) with regenerative signals and nanofibrous topography mimicking the native extracellular matrix have been shown to improve the outcome of alveolar ridge regeneration (ARR). This study developed a novel FGM with doxycycline-enamel matrix derivative (EMD) nanofibrous composites deposition to coordinate anti-inflammation and differentiation signals, thus facilitating ARR. Doxycycline-loaded PDLLA nanofibers (PD), EMD-loaded chitosan nanospheres (CE), and CE-embedded PD (CE-PD) were fabricated by electrospinning, deposited on the surfaces of barrier membrane to develop a FGM, and the efficacy was validated by delivering the FGM to regenerate experimental alveolar ridge defects in rats. Results revealed that PD had potent antibacterial capability, and CE-PD allowed sustained release of EMD to promote osteogenesis in vitro. In the alveolar ridge defects, FGM with PD on the outer surface downregulated MMP-8, and wound dehiscence was further reduced with Cbfa1 upregulation in those treated by FGM with CE-PD on the inner surface at 1 week. FGM with CE-PD revealed significantly greater new bone formation and defect fill at 4 weeks. In conclusion, FGM with PD reduced early tissue breakdown and with CE-PD nanofibrous composites accelerated wound healing and facilitated osteogenesis, and thus could be an advantageous strategy for ARR.