A 3D printing strategy for fabricating in situ topographical scaffolds using pluronic F-127

Topographical cues are one of the prerequisites for successful regeneration of muscle tissue. However, fabrication methods using three-dimensional (3D) bioprinters are limited by the simple nozzle-based extrusion or uncontrollability of photo-reactive systems. Hence, most studies on inducing topographical cues were focused on two-dimensional (2D) surface structures and based on imprinting and soft-lithography processes. Although 2D patterned surfaces provide outstanding insight into optimal patterned architectures by facilitating the analysis of various myoblast responses, it can be difficult to achieve complex 3D structures with microscale topographical cues. For this reason, we propose a new strategy for obtaining topographical cues in 3D printed synthetic biopolymers for regenerating muscle tissue. A uniaxially aligned pattern was obtained on the struts of the matrix composed of poly(epsilon-caprolactone) (PCL) or poly(lactic-co-glycolic acid) (PLGA), by taking advantage of the immiscible rheological properties and flow-induced force in the dispersed pluronic F-127 phase (sacrificial material) and matrix materials. To observe the effects of the topographical cues of the fabricated structures on cellular responses, including myogenic gene expression, myoblasts (C2C12 cells) were cultured for various lengths of time, and the micropatterned structure provided a rapid myotube formation, compared to the control, which did not undergo the microscale patterning process. In addition, to extend the printing technique, the alignment of primary tenocytes cultured on the uniaxial patterned structure was evaluated.