Pneumatic micro-extrusion (PME), a direct-write additive manufacturing process, has emerged as a high-resolution method for the fabrication of a wide range of biological tissues and organs. In the PME process, a high-pressure flow is injected into a barrel, which contains a polymer material, leading to pressure-driven material deposition on a free surface via a micro-capillary nozzle. In this study, PCL powder was loaded into the barrel, maintained at 120 °C. The flow pressure was set to 550 kPa. Laminar molten PCL flow was deposited on a glass surface (maintained at 45 °C), using a nozzle 200 μm in diameter. A porous, cylindrical scaffold was designed, having a diameter and height of 10 mm and 3 mm, respectively.To investigate the effects of the design and process parameters, an experiment was designed and conducted with the aim to investigate the effects of deposition head temperature, flow pressure, and infill pattern. Print speed was set at 0.35 mm/s. Layer height and layer width were set at 150 µm. In addition, infill density was set at 0.25. As a result, 16 experimental runs were characterized. Of each of the PME-fabricated samples, an image was acquired using a high-resolution CCD camera. Subsequently, the acquired images were analyzed using in-house digital image processing algorithms (developed in the MATLAB environment), forwarded with the aim to characterize both the diameter and the height of the fabricated bone scaffolds. Furthermore, the compression properties of the fabricated bone scaffolds were measured using a compression testing machine. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal functional properties for incorporation of stem cells toward the treatment of osseous fractures and defects.

Pneumatic Microextrusion-Based Additive Biofabrication of Polycaprolactone Bone Scaffolds – Part Ii: Investigation of the Influence of Polymer Flow Parameters

Paper Proceedings: https://asmedigitalcollection.asme.org/MSEC/MSEC2021/volume/85062

2021 International Manufacturing Science and Engineering Conference (MSEC2021)

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