Biocompatible Liquid Crystal Elastomer Optical Fiber Actuator for In Vivo Endoscopic Navigation and Laser Ablation Therapy

Abstract Photothermal‐responsive liquid crystal elastomers (LCEs) face critical barriers in biomedical applications: phase transition temperatures exceeding 80 °C risk thermal injury, and free‐space optical actuation fails in confined spaces. Here, a thiol‐ene crosslinked LCE is developed with a biocompatible phase transition temperature (37.6 °C), enabling safe actuation within biological tissues. Through coaxial extrusion, the fabrication of waveguide‐structured LCE optical fibers is pioneered, achieving ultralow optical loss (0.76 dB cm −1 ) and enabling long‐range light transmission and remote actuation via silica optical fiber coupling. Under 808 nm laser stimulation (375 mW), these LCE optical fibers generate 30% contraction strain in 23 s, maintaining maximum surface temperature < 48 °C. Integrated into an endoscopic system, LCE optical fibers replaced rigid mechanical components. Ex vivo characterization reveals their omnidirectional bending capability (94° angular range), while in vivo trials on live rats and rabbits validate their operational functionality in anatomical environments, enabling hemorrhage detection and laser‐steered tumor ablation via controlled navigation. Histopathological analysis confirms no thermal damage at fiber‐tissue interfaces. This work establishes biocompatible LCE optical fibers as a photonic platform integrating photonic‐driven soft actuation and tissue‐compliant adaptability, enabling mechanically safe interventions in confined anatomical environments.