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Laser-assisted bioprinting at different wavelengths and pulse durations with a metal dynamic release layer: A parametric study

(A) (B)

(C) (D)

Figure 5. Laser pulse characteristics of the Yb:YAG laser with different:(a, d) pulse durations and (b, c) pulse energies. (A) Pulses
with 8- to 200-ns time durations with similar peak power are measured and averaged over 1000 pulses with a photodiode and oscil-
loscope; (B) The temporal shape of the laser pulses (shown for 200-ns laser pulses) varies only slightly with pulse energies; (C) The
relation between the pulse energy and peak power for different pulse durations is nearly proportional; (D) The transversal mode (spa-
tial shape) of the laser pulses is nearly independent on pulse duration (shown for 8 and 200 ns).

(A) (B)

Figure 6. (A) Different combinations of pulse duration, energy, and peak power can result in similar printed droplet sizes; here, algi-
nate droplets with about 150–160 µm diameter were printed with different pulse durations and adjusted energy. (B) Printing with
different pulse durations (200 and 8 ns) and alginate layer thickness; the pulse energies were adjusted for similar printed droplet sizes
at 65-µm layer thickness (45-µL alginate). Keeping these two pulse energies constant, printing with different layer thicknesses was
tested. The printing result was similar for both pulse durations at 80-µm (55 µL) and 95-µm (65 µL) layer thickness. However, nearly
no hydrogel was printed with 200-ns pulses at layer thickness above 115 µm (80 µL and 90 µL), while many droplets were printed
with 8-ns pulses.
48 International Journal of Bioprinting (2017)–Volume 3, Issue 1