Polymeric silk fibroin hydrogel as a conductive and multifunctional adhesive for durable skin and epidermal electronics

• Published in: Smart medicine Vol. 3; no. 3; pp. e20240027 - n/a
• Main Authors: Fu, Fanfan, Liu, Changyi, Jiang, Zhenlin, Zhao, Qingyu, Shen, Aining, Wu, Yilun, Gu, Wenyi
• Format: Journal Article
• Language: English
• Published: Germany John Wiley and Sons Inc 01.09.2024; Wiley-VCH
• Subjects: epidermal electronics; flexible sensor; hydrogel adhesives; ionic conductive; silk fibroin; epidermal electronics; flexible sensor; ionic conductive; hydrogel adhesives; silk fibroin
• ISSN: 2751-1871; 2751-1863; 2751-1871
• DOI: 10.1002/SMMD.20240027

Silk fibroin (SF)‐based hydrogels are promising multifunctional adhesive candidates for real‐world applications in tissue engineering, implantable bioelectronics, artificial muscles, and artificial skin. However, developing conductive SF‐based hydrogels that are suitable for the micro‐physiological environment and maintain their physical and chemical properties over long periods of use remains challenging. Herein, we developed an ion‐conductive SF hydrogel composed of glycidyl methacrylate silk fibroin (SilMA) and bioionic liquid choline acylate (ChoA) polymer chains, together with the modification of acrylated thymine (ThyA) and adenine (AdeA) functional groups. The resulting polymeric ion‐conductive SF composite hydrogel demonstrated high bioactivity, strong adhesion strength, good mechanical compliance, and stretchability. The formed hydrogel network of ChoA chains can coordinate with the ionic strength in the micro‐physiological environment while maintaining the adaptive coefficient of expansion and stable mechanical properties. These features help to form a stable ion‐conducting channel for the hydrogel. Additionally, the hydrogel network modified with AdeA and ThyA, can provide a strong adhesion to the surface of a variety of substrates, including wet tissue through abundant hydrogen bonding. The biocompatible and ionic conductive SF composite hydrogels can be easily prepared and incorporated into flexible skin or epidermal sensing devices. Therefore, our polymeric SF‐based hydrogel has great potential and wide application to be an important component of many flexible electronic devices for personalized healthcare. We present an ion‐conducting SF composite hydrogel with the robust toughness and strong adhesion without compromising the high bioactivity. The bio‐cations surrounding the ChoA chains can provide a stable ion‐conducting channel for the whole hydrogel. The resulting composite hydrogel networks were also modified with acrylate adenine (AdeA) and acrylate thymine (ThyA), thus endowed the hydrogel (SF‐Cho/AT) with strong adhesion ability. Such an ion‐conducting SF polymeric hydrogel can be incorporated into wearable electronics for real‐time on‐body detection of various physical and electrical signals.