Fabrication of 3D-printed coiled PCL microfibrous bundles using alginate-based biocomposites for bone tissue engineering applications

Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional (3D) structures conducive to tissue regeneration. Coiled fibrous scaffolds have emerged as promising substrates owing to their ability to provide unique topographical cues. In this study, coiled poly (ε-caprolactone) (PCL) fibrous bundles were fabricated using an alginate-based composite system, and processed with 3D printing. The unique structure was obtained through the die-swell phenomenon related to the release of residual stresses from the printed strut, thereby transforming aligned PCL fibers into coiled structures. The effects of printing parameters, such as pneumatic pressure and nozzle moving speed, on fiber morphology were investigated to ensure a consistent formation of coiled PCL fibers. The resulting coiled PCL fibrous scaffold demonstrated higher activation of mechanotransduction signaling as well as upregulation of osteogenic-related genes in human adipose stem cells (hASCs), supporting its potential in bone tissue engineering.