3D-printed Multiphasic Micro-fibrous Scaffold by Melt Electrospinning for Periodontal Regeneration

Objectives: Periodontitis is a chronic inflammatory disease that results in the recession of the supporting soft and hard tissues around teeth, potentially leading to the loss of teeth. The complexity of the periodontium causes difficulties in regenerating tissues, leading to clinically unpredictable outcomes. Previous manufacturing methods, such as salt-leaching, FDM printing, and solution electrospinning, have been investigated but produce inflexible, low-resolution, random structures. In order to regenerate tissues for complex defects, we used melt electrospinning technique (MES) to produce customizable, micro-fibrous scaffolds permitting tight control over the architecture. Our hypothesis is multiphasic scaffolds 3D-printed by MES can promote more predictable and coordinated regeneration of soft and hard tissues, including periodontal ligament (PDL) and bone.
Methods: All scaffolds were 3D-printed with a 3D bioprinter using polycaprolactone with ~20um microfibers and a 1mm overall thickness. Three groups were established according to the structure design: (I) homogeneous pore-size (500μm), (II) 2-layered (250μm bottom-500μm top), or (III) 3-layered (250μm bottom-500μm middle-top with one direction) scaffolds. The scaffold's morphology, porosity, and ability to promote the proliferation and differentiation of PDL cells and osteoblasts were compared.
Results: SEM showed scaffolds were printed with excellent structural integrity and bonding between the fibers. μCT showed that scaffolds were highly interconnected with 90% porosity, thus enhancing cell infiltration and migration. Specifically, the top layer fibers of group III were highly aligned in one direction, consistent with PDL fiber guidance. Group II/III scaffolds were found to facilitate proliferation via immunofluorescence. 3D reconstruction revealed that PDL cells formed ligament-like, continuous cell sheets expressing high level collagen. Alizarin staining showed that differentiated osteoblasts on groups II/III deposited more calcium.
Conclusions: Multiphasic scaffolds have advantageous properties that promote cell proliferation, differentiation, and PDL guided orientation. Our study suggests that using multiphasic scaffolds fabricated with MES is a viable platform for regenerating tissue complexes, such as the periodontium.