Traditional wound dressings mainly participate in the passive healing processes and are rarely engaged in active wound healing by stimulating skin cell behaviors. Electrical stimulation (ES) has been known to regulate skin cell behaviors. Herein, a series of multifunctional hydrogels based on regenerated bacterial cellulose (rBC) and MXene (Ti 3 C 2 T x) are first developed that can electrically modulate cell behaviors for active skin wound healing under external ES. The composite hydrogel with 2 wt% MXene (rBC/MXene-2%) exhibits the highest electrical conductivity and the best biocompatibility. Meanwhile, the rBC/MXene-2% hydrogel presents desired mechanical properties, favorable flexibility, good biodegradability, and high water-uptake capacity. An in vivo study using a rat full-thickness defect model reveals that this rBC/MXene hydrogel exhibits a better therapeutic effect than the commercial Tegaderm film. More importantly, in vitro and in vivo data demonstrate that coupling with ES, the hydrogel can significantly enhance the proliferation activity of NIH3T3 cells and accelerate the wound healing process, as compared to non-ES controls. This study suggests that the biodegradable and electroactive rBC/MXene hydrogel is an appealing candidate as a wound dressing for skin wound healing, while also providing an effective synergistic therapeutic strategy for accelerating wound repair process through coupling ES with the hydrogel dressing.

Superhydrophobic surfaces repel water and other liquids such as tissue fluid, blood, urine, and pus, which can open up a new avenue for the development of biomedical devices and has led to promising advances across diverse fields, including plasma separator devices, blood-repellent sensors, vascular stents, and heart valves. Here, the fabrication of superhydrophobic liquid–solid contact triboelectric nanogenerators (TENGs) and their biomedical applications as droplet sensors are reported. Triboelectrification energy can be captured and released when droplets are colliding or slipping on the superhydrophobic layer. The developed superhydrophobic TENG possesses multiple advantages in terms of simple fabrication, bendability, self-cleaning, self-adhesiveness, high sensitivity, and repellency to not only water but also a variety of solutions, including blood with a contact angle of 158.6°. As a self-powered sensor, the developed prototypes of a drainage bottle droplet sensor and a smart intravenous injection monitor based on the superhydrophobic liquid–solid contact TENG can monitor the clinical drainage operation and intravenous infusion in real time, respectively. These prototypes suggest the potential merit of this superhydrophobic liquid–solid contact TENG in clinical application, paving the way for accurately monitoring clinical drainage operations and intravenous injection or blood transfusion in the future.

Electronic fibers used to fabricate wearable triboelectric nanogenerator (TENG) for harvesting human mechanical energy have been extensively explored. However, little attention is paid to their mutual advantages of environmental friendliness, mechanical properties, and stability. Here, we report a super-strong, biodegradable, and washable cellulose-based conductive macrofibers, which is prepared by wet-stretching and wet-twisting bacterial cellulose hydrogel incorporated with carbon nanotubes and polypyrrole. The cellulose-based conductive macrofibers possess high tensile strength of 449 MPa (able to lift 2 kg weights), good electrical conductivity (~ 5.32 S cm−1), and excellent stability (Tensile strength and conductivity only decrease by 6.7% and 8.1% after immersing in water for 1 day). The degradation experiment demonstrates macrofibers can be degraded within 108 h in the cellulase solution. The designed fabric-based TENG from the cellulose-base conductive macrofibers shows a maximum open-circuit voltage of 170 V, short-circuit current of 0.8 µA, and output power at 352 μW, which is capable of powering the commercial electronics by charging the capacitors. More importantly, the fabric-based TENGs can be attached to the human body and work as self-powered sensors to effectively monitor human motions. This study suggests the potential of biodegradable, super-strong, and washable conductive cellulose-based fiber for designing eco-friendly fabric-based TENG for energy harvesting and biomechanical monitoring.

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Currently, various electronic devices make our life more and more safe, healthy, and comfortable, but at the same time, they produce a large amount of nondegradable and nonrecyclable electronic waste that threatens our environment. In this work, we explore an environmentally friendly and flexible mechanical sensor that is biodegradable and recyclable. The sensor consists of a bacterial cellulose (BC) hydrogel as the matrix and imidazolium perchlorate (ImClO 4 ) molecular ferroelectric as the functional element, the hybrid of which possesses a high sensitivity of 4 mV kPa −1 and a wide operational range from 0.2 to 31.25 kPa, outperforming those of most devices based on conventional functional biomaterials. Moreover, the BC hydrogel can be fully degraded into glucose and oligosaccharides, while ImClO 4 can be recyclable and reused for the same devices, leaving no environmentally hazardous electronic waste.

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A biocompatible, flexible, yet robust conductive composite hydrogel (CCH) for wearable pressure/strain sensors has been achieved by an all-solution-based approach. The CCH is rationally constructed by in situ polymerization of aniline (An) monomers in the polyvinyl alcohol (PVA) matrix, followed by the cross-linking of PVA with glutaraldehyde (GA) as the cross-linker. The unique multiple synergetic networks in the CCH including strong chemical covalent bonds and abundance of weak physical cross-links, i.e., hydrogen bondings and electrostatic interactions, impart excellent mechanical strength (a fracture tensile strength of 1200 kPa), superior compressibility (ε = 80%@400 kPa), outstanding stretchability (a fracture strain of 670%), high sensitivity (0.62 kPa–1 at a pressure range of 0–1.0 kPa for pressure sensing and a gauge factor of 3.4 at a strain range of 0–300% for strain sensing, respectively), and prominent fatigue resistance (1500 cycling). As the flexible wearable sensor, the CCH is able to monitor different types of human motion and diagnostically distinguish speaking. As a proof of concept, a sensing device has been designed for the real-time detection of 2D distribution of weight or pressure, suggesting its promising potentials for electronic skin, human–machine interaction, and soft robot applications.

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