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Movement tracking with TrackMate

Videos were recorded at 120 fps and then converted to files at 30 fps, cut to the area of interest
and exported as uncompressed AVI files (8-bit, UYUY codec) with Premiere Pro (Adobe,

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USA). Movement speed of the microscaffolds was tracked via TrackMate plugin v6.0.3 in
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Fiji v 1.53c . After importing, the files were converted to greyscale, the ROI was set around
the central channel. Particles were detected using the Difference-of-Gaussian (DoG) detector

using 20 px, 2 px thresholds and no filters as settings. Using the quality filter, unneeded dots
were erased until only the main track was visible anymore. Using the Laplacian filter with a

maximum distance of 20 px and a segment gap closing of 20 px and 5 frames, the tracks were
generated. Filtering by track ID allowed to get the track speed of each microscaffold.

Fluorescence spectrum analysis of microconstructs
The fact that the produced microscaffolds are fluorescent, due to the presence of the PI in the

material, was leveraged for the on-the-fly detection and analysis process. The fluorescent
spectrum of BBs produced from ZrHyb was characterized by placing around 100

microscaffolds into a 96-well plate in 200 µl of 1-Propanol. The samples were excited at 360
nm and their emission spectrum was analyzed on a photometer (Synergy H1, BioTek) from

390 nm to 700 nm in intervals of 10 nm. The excitation wavelength was determined from

literature values stating that the photoinitiator showed the highest absorption potential at 365
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nm . The emission values were subtracted from the background signal emitted from the well
plate and the 1-Propanol.

Optical Detection Device

The optical detection mechanism was built using an excitation LED with a wavelength of 360-
370 nm and (3W370380m, Avonec GmbH). The LED was powered with a constant current

source (LDD-700LW, Mean Well) at 100% output. The light source was collimated and
focused using a condenser lens (ACL25416U, Thorlabs). Light splitting was performed via

dichroic mirror (DMLP490R, Thorlabs) housed in a metric filter mount (CM1-DCH/M,

Thorlabs). To distinguish between excitation and emission wavelength, a 500 nm long-pass
filter (62983, Edmund Optics) and a short-pass filter at 475 nm (84705, Edmund Optics) was

used. The LED light was positioned at a precise distance to the lens using a 3D printed holder.
The fluorescent excitation signal was detected with a photodiode (PDA100A2, Thorlabs). The

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