*2.7. UV-Vis Measurements*

Optical transmission of commercial PMMA and FDM printed PMMA with variable thickness was measured using a UV-visible spectrophotometer (Evolution 201, Thermo Fisher Scientific, Waltham, MA, USA).

### *2.8. Autofluorescence Measurements*

Fluorescence intensity was characterized for commercial PMMA substrates and 3D printed PMMA with a thickness of 2 mm using an inverted fluorescence microscope (DMi8, Leica, Wetzlar, Germany) with Cy5, Cy3, FITC and DAPI filters and 130 ms exposure.
