Electric-field assisted 3D-fibrous bioceramic-based scaffolds for bone tissue regeneration: Fabrication, characterization, and in vitro cellular activities

Nano/microfibrous structure can induce high cellular activities because of the topological similarity of the extracellular matrix, and thus, are widely used in various tissue regenerative materials. However, the fabrication of a bioceramic (high weight percent)-based 3D microfibrous structure is extremely difficult because of the low process-ability of bioceramics. In addition, three-dimensional (3D) microfibrous structure can induce more realistic cellular behavior when compared to that of 2D fibrous structure. Hence, the requirement of a 3D fibrous ceramic-based structure is an important issue in bioceramic scaffolds. In this study, a bioceramic (α-TCP)-based scaffold in which the weight fraction of the ceramic exceeded 70% was fabricated using an electrohydrodynamic printing (EHDP) process. The fabricated ceramic structure consisted of layer-by-layered struts entangled with polycaprolactone microfibers and the bioceramic phase. Various processing conditions (such as applied electric field, flow rate, nozzle size, and weight fraction of the bioceramic) were manipulated to obtain an optimal processing window. A 3D printed porous structure was used as a control, which had pore geometry similar to that of a structure fabricated using the EHDP process. Various physical and cellular activities using preosteoblasts (MC3T3-E1) helped confirm that the newly designed bioceramic scaffold demonstrated significantly high metabolic activity and mineralization.