Hierarchical fibrous collagen/poly(& epsilon;-caprolactone) structure fabricated with a 3D-printing process for tissue engineering applications

Hierarchical scaffolds have been extensively used in various tissue engineering applications as they can provide unique biofunctional properties, including biophysical cues, to successfully accomplish preferred cell attach-ment, growth, and differentiation depending on the target tissues. In this study, we propose a new strategy for fabricating hierarchical structures consisting of microfibrous collagen/poly(e-caprolactone) (PCL) bundles ob-tained using a 3D printing process supplemented with a unique bioink, plasma treatment, and collagen coating process. To obtain the hierarchical fibrous PCL structure, we used an alginate matrix hydrogel to form a microfibrous bundle of dispersed PCL components using elongational and shear stresses within a printing nozzle. By controlling various mixture ratios of alginate and PCL, processing temperature, pneumatic pressure, and nozzle moving speeds, a stable hierarchical structure consisting of PCL microfibers was obtained. To demonstrate the feasibility of hierarchical PCL-based structures coated with type I collagen, we investigated whether the construct affects the alignment and differentiation of myoblasts. The hierarchical fibrous biocomposite constructs presented a higher degree of myogenic activity than the control, which was fabricated using normal printing/ collagen coating processes. Furthermore, the hierarchical PCL structures were further elaborated using 10 x simulated body fluid (SBF) resulting in a scaffold consisting of a hydroxyapatite (HA) layer. The hierarchical collagen/PCL/HA structures were evaluated with the aim of obtaining a functional scaffold that could efficiently induce osteogenesis to the human adipose stem cells (hASCs). These in vitro results suggest that the fibrous composite structure can provide enhanced osteogenic activity compared to the normally printed control (collagen/PCL/HA).

Automated summary

In this study, a new strategy was proposed to fabricate hierarchical structures of microfibrous collagen/PCL bundles using a 3D printing process supplemented with bioink, plasma treatment, and collagen coating. The stable hierarchical structure consisting of PCL microfibers was obtained by controlling various parameters. The fibrous composite structure showed enhanced osteogenic activity compared to the control group.