Electrical writing of multi-responsive polysaccharide hydrogel enabling integration of programmable deformation and...

Smart hydrogels are capable of sensing and responding to external stimuli, demonstrating promising application in hydrogel actuators, soft robotics and other fields. The integration of hydrogel deformation with information encryption is important to help improve the storage density and security of information. In this study, a simple anodic electrical writing method is employed to graft catechol onto a chitosan/agarose double-network hydrogel, thereby enabling programmable spatial control of the patterned hydrogel. Meanwhile, the grafting process affects the physicochemical properties of the hydrogel, resulting in self-deformation in different solutions. Additionally, the introduction of dynamic boronate ester bonds endows the hydrogel with reversible multiple stimulus responsiveness (e.g., pH, glucose, and temperature), thus achieving reconfigurable deformation behaviors. The synergistic incorporation of electrically written information (Morse code) with the complex deformation of the hydrogel enables dual encryption. Owing to the redox property of catechol, different electrical signals can be generated in the written and unwritten areas. The security of the information is enhanced by using the electrical signals and Morse code for information reading. Furthermore, the hydrogel retains its deformation capability after 10 cycles, and information stored within the written area remains readable via electrical signals even after 30 days. This multi-responsive polysaccharide hydrogel prepared by electrical writing not only provides new insights for natural polysaccharide hydrogel actuators, but also stimulates their application potential in the field of information storage and encryption.