A high-performance biocompatible biomass-based fish gelatin organohydrogel strain sensor for long-term accurate plant growth monitoring

Organohydrogel-based plant strain sensors hold significant potential for enabling accurate and real-time monitoring of plant growth processes. However, existing strain sensors typically face challenges such as inferior biocompatibility, trade-off between sensing performance and mechanical properties, as well as poor long-term stability, leading to inaccurate monitoring and plant tissue damage and thus hindering their practical applications. Herein, we propose a synergistic metal ion and multiple hydrogen bond dual crosslinking strategy to develop a biomass-based fish gelatin organohydrogel as a strain sensing material. The resultant organohydrogel simultaneously exhibits excellent mechanical properties (Young's modulus of 99.9 kPa and strong adhesiveness of 60 kPa), high sensing performance (GF = 2.13, stable response across a wide temperature range from −80 °C to 25 °C), outstanding plant tissue and human cell biocompatibility, and long-term stability (over 5000 loading-unloading cycles under 100% strain), demonstrating superior overall performance to most existing organohydrogels. To harness these unique material performances, we fabricate a sandwich-structured plant strain sensor for long-term monitoring of plant growth. The fabricated strain sensor enables successful real-time monitoring of the growth dynamics of lotus stems and pomelo fruits with high accuracy and long-term stability up to three weeks. Our novel design strategy of high-performance organohydrogels enables high-fidelity plant growth monitoring, unlocking new potentials for advancing data-driven smart and precision farming practices.