Bioprinted aquatic plant-inspired soft machines for underwater environmental sensing

Abstract Aquatic plants combine porous, compliant stems with distributed leaves that interact with complex underwater environments, but these design principles remain unexplored in soft robotics. Here we translate the architecture and biomechanics of the submerged macrophyte Myriophyllum mattogrossense into bioprinted aquatic plant-inspired soft machines. High-resolution photon-based bioprinting produced wheel-like porous hydrogel stems with approximately 38% lower flexural rigidity than solid controls (15.6±2.1 versus 25.1±2.8 N mm²), enabling large deformations under external loading. We fabricated leaf-like structures using two cellulose-based hydrogel systems. Sodium alginate-hydroxyethyl cellulose hydrogels containing Chlamydomonas reinhardtii showed progressive greening and chlorophyll autofluorescence during culture. Nanocellulose-based poly(N-isopropylacrylamide) hydrogels underwent reversible shape changes in response to temperature and salinity, with curvature increasing 6.5-fold and 4-fold, respectively. Integrating these components produced an artificial aquatic plant-like machine that remained stable underwater while retaining the mechanical and responsive properties of its stem and leaf modules. These results establish aquatic plant architecture as a source of design principles for modular biohybrid soft machines and provide a foundation for underwater environmental sensing. This responsive platform offers a route towards adaptive underwater devices for environmental monitoring, ecological research and future biohybrid robotic applications across diverse, dynamic aquatic ecosystems.