3D-printed biodegradable soft robotic actuators using gelatin-gellan composite natural gel for sustainable and safe food automation.

The increasing reliance of the food industry on robotic automation faces critical challenges in ensuring human safety and preserving the integrity of delicate food products. Traditional rigid metal robots struggle to guarantee safe human-machine interaction, while synthetic polymer-based soft robots raise concerns over chemical contamination. This study introduces an innovative solution to fabricate food-safe soft robot actuators using a natural composite gel composed of fish gelatin (FG) and high acyl gellan gum (HG) via 3D printing. Eco-friendly cross-linking methods, including transglutaminase (TGase) treatment and ethanol modification, enhance the gel's mechanical and electrical performance, achieving a Young's modulus of 0.21 ± 0.02 MPa, tensile strength of 0.59 ± 0.02 MPa, and remarkable elasticity (454.1 % strain). These properties enable pneumatic actuators to withstand 125 kPa pressure and adaptively grip diverse food shapes without damage. Additionally, the gel's inherent electrical conductivity grants the robots embedded sensing capabilities. Crucially, the material is fully biodegradable within 35 days, addressing both food safety and environmental sustainability. By combining safety, adaptability, and eco-conscious design, this work pioneers a pathway toward next-generation sustainable automation in food processing.