The gripper body was stereolithography printed (Form 2, Formlabs, Somerville, MA, USA) with an elastic resin (Elastic V1, Shore A 50). The body is a hollow bell-like structure, with an inner diameter of 20 mm, a height of 12.5 mm and a wall thickness of 700 μm. An inlet with a diameter of 4 mm is at the apex of the bell-like structure. To fabricate the soft elastomer film, we spread silicone elastomer (Ecoflex™ 00–50, Smooth-On Inc., Macungie, PA, USA) onto a polyethylene terephthalate (PET) sheet by using a universal film applicator (UA 3000, Mtv Messtechnik oHG, Germany). The thickness of the elastomer film after curing was ~400 μm.
To bond the film to the gripper, we cleaned the gripper with oxygen plasma (PICO with RF Generator, Diener electronic, 20 s at 30 W). Immediately after plasma treatment, we dipped the gripper in a silicone adhesive (Sil-Poxy™, Smooth-On Inc., Macungie, PA, USA) and pressed onto the cured elastomer film. The same silicone adhesive was used to attach a silicone tube (∅ 2/4 mm) to the inlet.Fig. S1 shows a schematic of the fabrication method.
To bond the film to the gripper, we cleaned the gripper with oxygen plasma (PICO with RF Generator, Diener electronic, 20 s at 30 W). Immediately after plasma treatment, we dipped the gripper in a silicone adhesive (Sil-Poxy™, Smooth-On Inc., Macungie, PA, USA) and pressed onto the cured elastomer film. The same silicone adhesive was used to attach a silicone tube (∅ 2/4 mm) to the inlet.