Figure 3.

Three-dimensional printing strategies to improve microfluidic channel transparency. Two different strategies were used to 3D print microfluidic devices in PS: (a) printing directly onto the print bed (strategy I) and printing on top of a commercial PS foil (strategy II). (b,c) An exemplary Y-channel with a square cross-section channel of 600 µm widths and height printed using strategy I (scale bar 5 mm). The inherent layer structure reduces the transparency of the microchannels. (d,e) The same Y-chip as in (b) but printed with printing strategy II, resulting in a microfluidic channel with higher transparency in the region of interest (scale bar 600 µm).