Prusa i3 mk3

For the printing of the rods a commercially available FFF printer Prusa i3 MK3 (Prusa Research, Prague, Czech Republic) was used. The nozzles were made of hardened steel with diameters of 0.25 mm, 0.4 mm, and 0.5 mm.

The drug-loaded filaments were printed on a FDM 3D printer (Prusa i3 Mk3, Prusa Research, Prague, Czech Republic) to oral dosage forms in various geometries. The geometries were designed with Fusion 360^® (Autodesk, San Rafael, CA, USA) and sliced in Simplify3D^® (Simplify3D, Cincinnati, OH, USA) to obtain the desired G-code. The print temperature for the PVA-PDM filaments was set to 185 °C, the bed temperature to 60 °C and the printing speed was 20 mm/s. The printing temperature had to be increased for the EVA-LD formulation, as the filament was very flexible and could not be transported reliably through the nozzle by the conveying wheels in the print head at lower temperatures, as the filament would otherwise wrap around the wheels. To ensure a constant filament-flow through the nozzle, the temperature of the nozzle was set to 220 °C and the printing speed was reduced to 10 mm/s. For the PVA-PZQ formulation, a nozzle temperature of 185 °C could again be used, but the bed temperature had to be increased to 90 °C because the printed objects adhered poorly to the print bed and detached from the bed more often. Therefore, a printing speed of 10 mm/s was also selected here. To obtain high print accuracy, the layer height was set to 0.1 mm and the extrusion width to 0.4 mm using a nozzle with a diameter of 0.4 mm. The infill percentage of the concentric infill was set to 100%.

The design and fabrication steps of the pneumatic actuator were adapted from the Soft Robotics Toolkit^{50 (link)}. The dimensions of the actuator were slightly changed: the actuator chambers had a length of 77 mm, a width of 15 mm wide, and a height of 12 mm. Detailed drawings of the actuators are provided in the supplementary material (Supplementary Fig. 13). We cast soft silicone (Dragon skin 30, Smooth-On) to 3D printed molds made out of polylactic acid (PLA, Prusa I3 MK3, Prusa Research). The actuator was molded in two parts: an upper part including the pneumatic chambers and a lower part including the strain-limiting layer (a glass fiber net). The parts were bonded together by spreading a thin layer of the same silicone between the parts. An air inlet was added to the actuator by first using a biopsy punch and then attaching a tube to the punched hole. The pneumatic strain gauge was glued to the bottom of the actuator with a thin layer of silicone.