Fig. 3: Swimmer biobots. High Reynold Swimmers.

A i, ii. a fish-like biobot with muscle tissue on both sides of the biobot enhancing the locomotion and directionality of the system. ii. The movement results of the system showing great locomotive abilities of the setup⁵⁴. Reprinted with permission from AAAS. B The Medusoid; The biobot inspired by jellyfish. i. comparison of muscle alignment and form of actual jellyfish (top) and the fabricated jellyfish biobot which is called medusoid. The microscopic results of the cell alignment show great similarities between the two. ii. The moving mechanism of the medusoid with fast contractions and slow recoil making it move upwards. iii. The angular velocity comparison between the jellyfish and the fabricated medusoid showing better functionality of the medusoid in long term¹⁰. Reprinted with permission from Springer Nature. C Ray-inspired swimming biobot. i. cell alignment comparison between the actual ray(top) and the fabricated biobot(bottom) showing great similarity between the two. ii. Different muscle circuits with pre-programmed patterns of activation for sequential muscle activation. The design with dense serpentine traces has higher number of traveling waves. iii. The movement of the ray across the obstacles on its way depicting promising controllability and locomotion¹². Reprinted with permission from AAAS. Low-Reynold Swimmers: (D) i. a sperm-like micro biobot with the cell location near its head allowing movement of the system. ii. The movement of the system during the experiment shows bending and straightening¹¹. Reprinted with permission from Springer Nature. E magnetically controlled sperm bot⁵⁶. Reprinted with permission from John Wiley and Sons. F i. overall schematic of a neuromodulated microswimmer biobot. The idea is to penetrate the muscle ring with neurite outgrowth. iii. Two designs were created. One flagellum, and two flagella swimmers. iv. The results show that the system with 2 flagella was by far faster than its 1 flagellum counterpart¹⁸. Reprinted with permission from PNAS. G i. Biobot swimmer with curved tails highlighting the role of angular displacement of tails for propulsion. ii. location of motor neurons, muscle and ECM illustrating the actuation unit and its culture mechanism. iii. Diagram of the swimming position of the system⁵⁸. Reprinted with permission from AAAS. H Swimmer Jellyfish. (i) Swim controller (inactive) embedded into a free- swimming jellyfish. (ii) Square wave signal generated by the swim controller. (iii) Simplified schematics (Bottom) of A. aurita anatomy. (iv) A. aurita medusae were placed subumbrellar surface up for muscle stimulation experiments. (v) Schematic of vertical free-swimming experiments (vi) Swimming speeds and enhancement factors for 0, 0.25, 0.38, 0.50, 0.62, 0.75, 0.88, and 1.00 Hz swim controller frequencies. Scale bars, 1 cm [H (i)], 2 cm [H(iv)]. Reprinted with permission from AAAS⁷¹.