Mandrel-free fabrication of giant spring-index and stroke muscles for diverse applications. - Zhang, Mengmeng; Fang, Shaoli; Cai, Wenting; Huynh, Chi; Göktepe, Fatma; Oh, Jiyoung; Wang, Zhong; Ekanayake, Ishara; Göktepe, Özer; Baughman, Ray H. (Science, 2025)