High performance multifunctional bio-gel sensor prepared with konjac glucomannan and κ-carrageenan

In this study, a novel multifunctional biosensor was developed based on the synergistic cross-linking of Konjac glucomannan (KGM) and κ-Carrageenan (KC). This biosensor exhibits high sensitivity for detecting triple signals: temperature, humidity, and strain. This matrix demonstrates excellent mechanical toughness (elongation at break >300 %) and a low Young's modulus (173.017 ± 1.51 kPa). This material exhibits a high thermal sensitivity of 1.67 %°C⁻¹ in temperature detection, and a linear response range of −15 % to 45 % was achieved within the temperature range of 4–40 °C. For humidity sensing, it provides a three-stage linear response with sensitivities of −89.75 %/% RH (0–40 % RH), −182.21 %/% RH (40–75 % RH), and −53.45 %/% RH (75–95 % RH). In terms of the strain sensing performance, this material demonstrates excellent wide-range detection capability (1–350 % strain), with a response value of approximately 875 %, and it also has high sensitivity (GF = 2.54 ± 0.06). Compared with traditional biomass-based gel sensors, the response limit of this sensor has been significantly increased while maintaining higher sensitivity. Experiments confirmed that the sensor can be monitored via resistance signals and exhibits stable performance (>2000 cycles) in flexible wearable applications such as human breathing monitoring and joint motion tracking, offering an innovative solution for intelligent medical monitoring and environmentally friendly electronic skin development.