Highly Stretchable and Self-Adhesive Wearable Biosensor Based on Nanozyme-Catalyzed Conductive Hydrogels

Abstract

A highly stretchable and self-adhesive wearable biosensor is prepared from nanozyme-catalyzed conductive hydrogels. The hydrogels are first prepared from a nanozyme (Ta–Ag) based on polyphenol (tannic acid, Ta) chelate with metal ions (silver ion, Ag+), which possesses peroxidase (POD)-like activity. After that, a huge number of free radicals are formed by the interaction between the Ta–Ag NPs and ammonium persulfate (APS), which initiate the hydrogel polymerization via a facile “one-pot” compositing strategy without ultraviolet (UV) or thermal treatment. The homogeneous distribution of nanozymes in the interpenetrating network of sodium alginate (SA) and polyacrylamide (PAAm) realizes a dermis-mimicking structure in the flexible conductor, named Ta–Ag–SA/PAAm. It simultaneously improves the mechanical properties and conductivity. Similar to the adhesion of mussels, the nanozymes contain abundant phenolic hydroxyl groups, favoring the adhesiveness of hydrogels. Due to the capability of changing conductivity with the strain, the obtained hydrogels are able to accurately monitor different amplitudes of human activities in real time. In addition, the Ta–Ag nanozyme exhibits a good bacterial adhesion capability and thereby enhances the bactericidal efficiency of Ag. Based on the high performance of sensing and antibacterial activity, the obtained Ta–Ag–SA/PAAm hydrogels can be a promising candidate for a broad range of applications, such as adhesive epidemic biosensors and wearable medical patches.

Comfortable, Anisotropic-Elastic, and Multilayered Fibrous Bandages with Enhanced Directional Tensile Performance

“…Elastic bandages, serving as essential first-aid items, effectively halt bleeding, minimize swelling, and fit well into the human body contour, thereby preventing secondary injury and facilitating recovery. They have been widely used in rehabilitation training, wound healing, , and health care . Recently, with the latest developments in training theory, the ideal bandage is considered to be a porous soft material with directional tensile performance along the length direction that provides fixation pressure to an injured body part without hindering the normal movements of other body parts, i.e., offers comfortable and anisotropic-elastic function .…”

Enhancing Mechanical and Sensing Performance of Conductive Hydrogel via Ga-Droplet Costabilization with Polyaniline and Xanthan Gum

“…In recent years, there has been significant interest in conductive hydrogels for wearable electronic devices, comprising chemically or physically cross-linked polymer networks, uniformly dispersed conductive fillers, and high water content. − While many of these hydrogels demonstrate favorable mechanical properties and impressive stretchability, they often fall short in terms of conductivity or sensitivity. Conversely, those with exceptional conductivity and sensitivity tend to sacrifice flexibility and lack self-healing capabilities.…”