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(MCWHL5; Thorlabs). A delay generator (DG535, Stanford Research Systems) and a photodiode

(DET10A, Thorlabs) were used to trigger image capturing at the desired time delays with respect
to laser firing.

Microscopy images of printed drops were processed using a custom MATLAB script to quantify
droplet placement error. The droplet placement error was calculated as the distance between the

intended and actual drop landing positions. Droplet circularity, splatter coverage, and area were

calculated using ImageJ and its built-in image processing tools. Splatter coverage was defined as
the ratio of the total satellite drop area to the total main drop area.

2.3. Mobile LIST printing head

The core printing component of the mobile printing head is a glass microcapillary (8250; Vitrocom,

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inner dimensions: 500 × 500 μm; wall thickness: 100 μm) continuously perfused with ink . The
capillary features a femtosecond laser-machined 200 µm circular opening on one of its sides, acting

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as a nozzle . Laser pulses from a pulsed 532 nm Nd:YAG laser (Nano S 60 30; Litron Lasers, 6
ns pulse duration) are used to generate microjets. Unlike our previous work that employed an open
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beam delivery system , the laser is now coupled to a 105 µm core optical fiber (FG105LCA;
Thorlabs), with the fiber fixed to the glass capillary opposite the laser-machined opening using a

3D-printed holder. This 3D-printed holder also incorporates clamps for the interchange of
capillaries and tubing guides, securing both the tubing and fiber, with the entire assembly

comprising the mobile printing head. A detailed 3D CAD rendering of the print head can be found
in Figure S1. A syringe pump (NE 1000; New Era Pump Systems Inc.) and perfusion tubing

(89404-042; VWR) are used to continuously perfuse ink through the microcapillary at flow rates
between 4 µL/min and 12 µL/min. The ink does not leak from the nozzle due to surface tension,

and microjets are only generated when the delivered laser pulse induces bubble formation and a

pressure increase inside the capillary.

2.3. Robotic arm integration and OCT-based distance tracking system

The mobile LIST printing head was mounted on a 5-axis robotic arm (Dorna 2, Dorna Robotics).
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To simulate the physiological movement of the chest during breathing , microscope slides used
as printing substrates were displaced in the z-axis with a 12 mm amplitude (24 mm peak-to-peak
displacement) and a frequency of 0.2 Hz using a translation stage (Z825B, Thorlabs). The printing

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