Dear Colleagues,

A hydrogel is a network system of polymers with a hydrophilic three-dimensional network cross-linked structure which can maintain a certain shape and absorb a large amount of water. Hydrogels have good biocompatibility and biodegradability; thus, these materials are widely used in drug delivery, tissue regeneration and other fields thanks to their excellent properties, making an indelible contribution to the development of biomedicine. Soft and stretchable materials based on hydrogels have skin/tissue-like mechanical properties, providing new avenues for the design and manufacture of wearable devices and flexible electronics. Hydrogels have mechanical and physiological properties similar to those of various organs in the human body, and have both electrical, mechanical, and biological functions which are controllable and diverse, making these materials one of the most ideal carriers of human–machine interfaces. Using bio-hydrogels as encapsulation materials, the development of fully degradable, implantable hydrogel-based flexible electronics in the human body will be a promising development direction. Although hydrogel-based flexible electronic devices have developed rapidly, many problems remain unresolved, such as adhesion of the hydrogel interface, hydrogel dehydration, and processing. We believe that it is time to re-examine the application of gels in flexible electronic devices to enable new developments and application directions for hydrogels. We look forward to submissions reporting new results on gel-based devices and flexible electronics, and welcome the submission of both theoretical and experimental studies.

Dr. Lili Qiu
Prof. Dr. Zihui Meng
Guest Editors

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• hydrogel
• human–machine interface
• gel-based devices
• flexible electronics