Fig. 3. Pneumatic and hydraulic artificial muscles.

a A soft pneumatic actuator that can extend from the tip⁷¹. Copyright 2017 by AAAS. Reprinted with permission. b A fully soft autonomous robot⁶⁹. Copyright 2016 by Springer Nature. Reprinted with permission. c A PDMS micro tentacle with spiral bending capability⁶⁰. Reproduced from ref. ⁶⁰ (2019, CC BY 4.0). d An artificial gripper using magnetically induced liquid-to-gas phase transitions⁷³. Copyright 2020 by AAAS. Reprinted with permission. e A flexible fluidic microactuator⁶⁴. Reproduced from ref. ⁶⁴ (2016, CC BY 4.0). f Soft microfingers for cellular aggregate manipulation⁷⁵. Reproduced from ref. ⁷⁵ (2016, CC BY 4.0). g Soft electropneumatic pumps⁷⁶. Copyright 2021 by AAAS. Reprinted with permission