Inspired by natural muscle, a key challenge in soft robotics is to develop self-contained electrically driven soft actuators with high strain density. Various characteristics of existing technologies, such as the high voltages required to trigger electroactive polymers ( > 1KV), low strain ( < 10%) of shape memory alloys and the need for external compressors and pressure-regulating components for hydraulic or pneumatic fluidicelastomer actuators, limit their practicality for untethered applications. Here we show a single self-contained soft robust composite material that combines the elastic properties of a polymeric matrix and the extreme volume change accompanying liquid–vapor transition. The material combines a high strain (up to 900%) and correspondingly high stress (up to 1.3 MPa) with low density (0.84 g cm−3). Along with its extremely low cost (about 3 cent per gram), simplicity of fabrication and environment-friendliness, these properties could enable new kinds of electrically driven entirely soft robots.

S75dd-cfDNA levels between 13 rejection, 14 post-rejection, and 217 non-rejection samples (R vs NR, p= 0.96), and no significant difference in dd-cfDNA levels between biopsy grades (132 OR, 103 1R, and 8 2R samples; p= 0.85 for OR vs ≥ 2R). Of interest was the observation that dd-cfDNA levels rose prior to rejection in 3/5 patients, and decreased post-rejection in 5/8 patients; and patients with only Grade 0 biopsies had consistently low dd-cfDNA levels. Conclusion:With approximately half of this pediatric cohort tested, we found no difference in dd-cfDNA levels between biopsy grades or in pediatric patients with treated acute rejection events. Additional studies are required to determine why the positive results reported in adults were not replicated in children.