Fig. 4

Absorbance measurement in a 3D printed microfluidic device. A CAD model of a device with five chambers for direct absorbance measurements on chip. B Microfluidic device in a 96-well-plate-adapter for measurement with a plate reader. C Test device 3D printed from poly (methyl methacrylate) (PMMA) with a dilution series of dye solution (left to right: 1:1, 1:2, 1:4 and 1:8). Scale bar measures 10 mm. D Absorbance spectra of 38.5 µl fluid 2 (same volume as in 3D printed device) in various dilutions (1:1, 1:2, 1:4 and 1:8) in PBS measured in a commercially available 96-well plate. E Absorbance spectra of fluid 2 at various dilutions (1:1, 1:2, 1:4 and 1:8) in PBS measured in 3D printed test device. Values are shown as mean ± SD (shown as area) of 3 devices