Ar g1l

The proposed package structure was fabricated using a 3D printer (AGILISTA-3200, Keyence Corporation, Osaka, Japan) to form the cover, rubber shim, and frame. The material used for the cover and frame was acrylic (AR-M2, Keyence Corporation, Japan), and the material used for the rubber shim was low-hardness silicone rubber (AR-G1L, Keyence Corporation, Japan). The cover was disk shaped with a thickness of 1 mm and a radius of 5 mm. The rubber shim was a circular disk with a hole of an inner diameter of 8 mm, outer diameter of 10 mm, and height of 0.8 mm. The frame was circular with a hole of an inner diameter of 10 mm, outer diameter of 14 mm, and height of 1.8 mm. The silicon pressure sensors were soldered to a standard glass epoxy PCB substrate with a thickness of 1.6 mm. The sensor mounting and assembly were operated with conventional chip mounter (MRS-850RD, Okuhara Electric Corporation, Tokyo, Japan). The measured assembly error of the sensor chip was 40 μm in the height direction.

Two methods and four materials were used to fabricate the soft actuators. Two methods are: (1) the traditional casting process, (2) 3D printing using the Objet350 Connex3 printer (Stratasys, Minnesota, USA) and the Agilista printer (Keyence, Japan). Four materials are: (1) the Dragon Skin 10 (Smooth-on Inc., PA, USA), (2) the Ecoflex (Smooth-on Inc., PA, USA), (3) the TangoPlus or TangoBlackPlus (Stratasys, MN, USA), which mainly consists of propenoic acid, ethyl ester, and trimethylbicyclo, and has a hardness of Shore A26-A28 and an elongation at break of 170–220%, and (4) the AR-G1L (Keyence, Japan), which mainly consists of silicone and acrylate monomer, and has a hardness of Shore A35 and an elongation at break of 160%.

To create the 3D-printed models, all digitally created models were exported in the.stl format to transform them into printable files. Files were imported in the respective slicing software depending on the printer type. Whole heart models and cross-sections of the left ventricle were printed using a rigid white material (White_v4, Formlabs Inc., Somerville, MA, USA) on a Formlabs Form 3 (Formlabs Inc.) (Figures 2A,B). Layer height was set to the most precise setting (0.05 mm). After printing, models were post processed according to manufacturer's instructions. For the models of the aortic arch, a flexible printing material (AR-G1L, Keyence Co., Osaka, Japan) was selected and printed using a commercial Polyjet printer (Agilista 3200W, Keyence Co.). A commercial surgical aortic graft (28 mm Gelweave, Vascutek Ltd., Renfrewshire, UK) was sutured to the open model, to create a realistic version of the repaired aorta (Figure 2C). A mechanical heart valve (21 mm On-X, CryoLife Inc, Kennesaw, GA, USA) and a plastic version of a biological heart valve were used as props to explain the SAVR procedure (Figure 2B).