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International Journal of Bioprinting Nozzle optimization for multi-ink bioprinting

Figure 6. Nozzle proposal for switching 2 and 0.5 wt% SA inks with high efficiency. (A) Schematics of the T-junction nozzle, asymmetrical nozzle, and
cross nozzle prepared for simulation and experiment. (B) Switching efficiency (Se) of the T-junction, asymmetrical, and cross nozzles. “N” indicates that
switching did not occur within 20 s. (C) Cross nozzle fabricated using a vat polymerization-based printer; scale bar = 1 mm. (D) Comparison of the
transition length between cross and T-junction nozzles based on printing experiments. Experimental data were obtained five times for each sample. Data
are expressed as mean ± S.D.; * p < 0.05.

anticipated that the ink switching would occur more with various nozzle shapes and ink combinations through
rapidly in a nozzle with modified corners. Consequently, numerical simulation, enhancing our understanding
the corners of the T-junction nozzle were trimmed, as and capabilities in nozzle design for bioprinting. Future
shown in Figure 7B. This modification facilitated smoother modifications could include incorporating additional
ink switching compared with the standard T-junction parameters such as diffusion coefficients and other fluid
nozzle. Furthermore, the transition length in the corner- models into the simulations to further refine nozzle designs
shaved nozzle was measured and illustrated in Figure for multi-ink printing.
7C. In this configuration, the SA ink transitioned more
smoothly than that in a conventional T-junction nozzle, 4. Limitations and future perspective
as depicted in Figure 7D. The widths of the transition We explored proposals for constructing 3D structures
area of printed line structures were 1.7–2.2 mm, which with a higher resolution. Our findings demonstrate that
showed no significant difference, as shown in Figure utilizing both numerical and experimental approaches
S6A, Supporting Information. Figure S6B, Supporting is effective for designing a single nozzle for multi-ink
Information, shows the transition areas of printed line printing. However, transition lengths exceeding 5 mm
structures. This methodology allowed us to experiment are inadequate for achieving the micro-scale structures

Volume 10 Issue 5 (2024) 163 doi: 10.36922/ijb.4091