Development of a Disposable Single-Nozzle Printhead for 3D Bioprinting of Continuous Multi-Material Constructs

Abstract

Fabricating multi-cell constructs in complex geometries is essential in the field of tissue engineering, and three-dimensional (3D) bioprinting is widely used for this purpose. To enhance the biological and mechanical integrity of the printed constructs, continuous single-nozzle printing is required. In this paper, a novel single-nozzle printhead for 3D bioprinting of multi-material constructs was developed and characterized. The single-nozzle multi-material bioprinting was achieved via a disposable, inexpensive, multi-fuse IV extension set; the printhead can print up to four different biomaterials. The transition distance of the developed printhead was characterized over a range of pressures and needle inner diameters. Finally, the transition distance was decreased by applying a silicon coating to the inner channels of the printhead.

Keywords: 3D bioprinting; continuous multi-material printing; multi-material printing; single-nozzle printing.

Figure 1

(a) Assembly of the SNMM printhead on a commercial BioX 3D bioprinter, (b) schematic diagram of the SNMM printing set-up.

Figure 2

Image analysis of the printed red and blue bioinks. (a) converting of the cropped image to black and white to detect the filament edges, (b) cropping the transition area of the printed pattern, (c) determining the transition distance within 90% of the maximum red value to 10% of the maximum red value while switching from red to blue (d) identifying the rate of change in the transition distance (D_tr = 0.03060 × t), where D_tr is the transition distance (in mm) and t is time (in·s).

Figure 3

Comparison of a 30 mm × 30 mm square printed by (a) the commercially available multi-head bioprinter and (b) the developed SNMM printhead.

Figure 4

Different geometries printed with the SNMM printhead: (a) cylinder (10 mm diameter, 5 mm height) using a 430 µm nozzle, (b) square (50 mm × 50 mm) using a 200 µm nozzle and (c) UPEI letters using a 430 µm nozzle. (d) Printhead path and transition of bioinks in UPEI letters.

Figure 5

Characterization of the transition distance based on pressure in regular and silicone-coated printheads in different nozzle sizes: (a) 250 µm, (b) 330 µm, and (c) 430 µm.