Fig. 5. Functional heart pump, printed in a single process.

a, A mammalian-heart-inspired soft-rigid hybrid pump printed in one process. Two of its four chambers are fluidically actuated and equipped with sensors. b, Illustration of the pump (i) with rigid thiol-ene parts shown in blue and soft thiol-ene parts visualized in pink. (ii) Cross section cut of the heart showing the internal sensor cavity, the position of the one-way valves, the actuation membrane and the inlet for air actuation. c, Sequential still images for the pump cycle showing a sketch of the pump’s cross section inside view. The cyclic change in actuation pressure P_act compared with atmospheric pressure P_atm and the resultant liquid flow are indicated. d, Three design iterations of the printed valve. (i) A thin, soft membrane that was prone to invert on itself under pressure. (ii) A thicker membrane that was still not strong enough to avoid inversion. (iii) A functional membrane with internal, rigid reinforcement. e, Heart pump connected to three liquid tanks. This setup was inspired by the mammalian cardiovascular system. A microcontroller is used to read the sensor data and a piston setup is used to provide actuation pressure. f, The pump setup can move liquid in relation to the applied pump rate. A maximum flow rate of 2.3 l min⁻¹ at 90 beats min⁻¹ was measured. g, The correlation of the commanded signal to the sensed chamber pressure at 60 beats min⁻¹.