Fabrication of 3D bioactive melt electrowriting composite scaffold with high osteogenic potential

A key challenge in using melt electrowriting (MEW) technology is incorporating large amounts of bioactive inorganic materials, such as hydroxyapatite (HA). In the present study, following optimization of the fabrication parameters, 40 %-HA (HA40) nanoparticles were pre-mixed into medical-grade polycaprolactone (PCL) and processed using the MEW (MEW) technique to mimic the structure and function of the natural extracellular matrix (ECM) for bone regeneration. The HA40 fibrous composite scaffolds showed continuous writing and obtained a well-connected and orderly stacked fibre with a small diameter size (67 ± 8.5 µm). A major result of the present study was the successful enrichment and accumulation of the HA particles, which mostly occurred on the MEW fibre external surfaces. This design allows for direct interfacial interaction with human periodontal ligament cells (hPDLCs). We systematically investigated the behaviour and function of hPDLCs on the HA40 composite scaffold, alongside parameters related to mineralization. The HA40 scaffold demonstrated significantly higher metabolic activity and enhanced expression of osteopontin compared to PCL-only scaffolds, as well as increased levels of ALP and COL1. The study's findings demonstrate that bioactive composite scaffolds, incorporating 40 % HA into m-PCL via MEW, effectively enhance the biological response of the ECM and are promising for potential applications in bone regeneration.