For fiber bioprinting optimization, we performed two major steps: definition of optimal flow rate and printing speed. Firstly, we printed serpentines with three different flow rates (43.34 ± 5.77, 86.68 ± 5.77 and 116.69 ± 5.77 µL/min) corresponding to E100, E150 and E200 in the gcode file. After defining optimal flow rate, four printing speeds (5, 10, 15 and 20 mm/s) were evaluated. All tests were performed at room temperature using a 25G (inner diameter 0.26 mm) plastic conical needle and glass microscope slides as printing surface. CAD files were designed in
Solidworks 2020 (Dassault Systèmes SOLIDWORKS Corp., Waltham, MA, USA) and processed with Ultimaker Cura 4.7. Images of the fibers were acquired with an inverted microscope (Olympus IX73 SC180 CSD) at 4× magnification and analyzed with ImageJ (NIH, Bethesda, MD, USA) software [14 (
link)].
For each serpentine printed, we analyzed their ability to maintain the desired shape upon deposition by computing the spreading ratio Equation (1) [15 (
link)]:
Fifteen measures of the fibers were taken (
Figure 2A) and then, the average spreading ratio was evaluated. According to the results, we defined optimal parameters in order to achieve continuous, homogeneous fiber deposition, and the lowest spreading ratio.
De Stefano P., Briatico-Vangosa F., Bianchi E., Pellegata A.F., Hartung de Hartungen A., Corti P, & Dubini G. (2021). Bioprinting of Matrigel Scaffolds for Cancer Research. Polymers, 13(12), 2026.