3D printed lost-wax casted soft silicone monoblocks enable heart-inspired pumping by internal combustion

Today's engines are essentially adapted from rigid parts. This inevitably results from the use of moving parts, bearing substantial mechanical load at considerable power density,(1,2) which usually have to be kept within very narrow dimensional margins. In nature, the structural integrity of many developed organisms is maintained by e. g. chitin or bones.(3,4) In contrast, some organisms (e. g. worms and slugs) and a lot of constituents in animate systems even get along completely without any solids (i. e. a heart muscle).(5,6) Such so. systems provide the fundamental advantage of high. exibility with good running features even under considerable deformation at comparably low weight.(7-9) Here however, classical engineering concepts such as torque transmission are of limited validity and thus put contraction and expansion forward. Advances in robotics have revealed fascinating prospects in so. machining for locomotion or grabbing. The prevalent mobilization method is based on pneumatics,(10-12) however also stimulation by electric charge(13-18) and magnetic fields(19) have been elaborated. Recently, Whitesides et al. have pointed out that internal combustion in so. structures (by methane-oxygen mixtures) can substantially enhance actuation response and power characteristics compared to common approaches by e. g. pressurized air,(20) Hydrocarbon based energy carriers are very lightweight compared to other power sources such as batteries.(21)