Nanostructured ionic hydrogel with integrated conductivity, stretchability and thermal responsiveness for a high-performance strain and temperature sensor.

Ionic conductive hydrogels are promising candidates for fabricating wearable sensors for human motion detection and disease diagnosis, and electronic skin. However, most of the existing ionic conductive hydrogel-based sensors primarily respond to a single-strain stimulus. Only a few ionic conductive hydrogels can respond to multiple physiological signals. Although some studies have explored multi-stimulus sensors, such as those detecting strain and temperature, the ability to identify the type of stimulus remains a challenge, which limits their applications. Herein, a multi-responsive nanostructured ionic conductive hydrogel was successfully developed by crosslinking the thermally sensitive poly(N-isopropylacrylamide-co-ionic liquid) conductive nanogel (PNI NG) with a poly(sulfobetaine methacrylate-co-ionic liquid) (PSI) network. The resultant hydrogel (PNI NG@PSI) was endowed with good mechanical stretchability (300%), resilience and fatigue resistance, and excellent conductivity (2.4 S m-1). Furthermore, the hydrogel exhibited a sensitive and stable electrical signal response and has a potential application in human motion detection. Moreover, the introduction of a nanostructured thermally responsive PNIPAAm network also endowed it with a sensitive and unique thermal-sensing ability to timely and accurately record temperature changes in the range of 30-45 °C, holding promise for application as a wearable temperature sensor to detect fever or inflammation in the human body. In particular, as a dual strain-temperature sensor, the hydrogel demonstrated an excellent capability of distinguishing the type of stimulus from superposed strain-temperature stimuli via electrical signals. Therefore, the implementation of the proposed hydrogel in wearable multi-signal sensors provides a new strategy for different applications, such as health monitoring and human-machine interactions.

Nanomaterials-Based Wound Dressing for Advanced Management of Infected Wound.

The effective prevention and treatment of bacterial infections is imperative to wound repair and the improvement of patient outcomes. In recent years, nanomaterials have been extensively applied in infection control and wound healing due to their special physiochemical and biological properties. Incorporating antibacterial nanomaterials into wound dressing has been associated with improved biosafety and enhanced treatment outcomes compared to naked nanomaterials. In this review, we discuss progress in the application of nanomaterial-based wound dressings for advanced management of infected wounds. Focus is given to antibacterial therapy as well as the all-in-one detection and treatment of bacterial infections. Notably, we highlight progress in the use of nanoparticles with intrinsic antibacterial performances, such as metals and metal oxide nanoparticles that are capable of killing bacteria and reducing the drug-resistance of bacteria through multiple antimicrobial mechanisms. In addition, we discuss nanomaterials that have been proven to be ideal drug carriers for the delivery and release of antimicrobials either in passive or in stimuli-responsive manners. Focus is given to nanomaterials with the ability to kill bacteria based on the photo-triggered heat (photothermal therapy) or ROS (photodynamic therapy), due to their unparalleled advantages in infection control. Moreover, we highlight examples of intelligent nanomaterial-based wound dressings that can detect bacterial infections in-situ while providing timely antibacterial therapy for enhanced management of infected wounds. Finally, we highlight challenges associated with the current nanomaterial-based wound dressings and provide further perspectives for future improvement of wound healing.

A Polyaniline Nanoparticles Crosslinked Hydrogel with Excellent Photothermal Antibacterial and Mechanical Properties for Wound Dressing.

Antibacterial hydrogel wound dressing is highly desirable in wound healing and infection control. However, the development of antibacterial hydrogels with controllable antibacterial properties and adequate mechanical properties without bacterial resistance and potential toxicity remains a challenge. Herein, a double bonds-ended polyaniline nanoparticle (Me-PANI NP) is synthesized, which can convert light energy into heat upon near-infrared (NIR) irradiation, and it is used as a novel photothermal antibacterial agent. The obtained bonds-ended Me-PANI NPs are subsequently involved in polyacrylamide (PAM) polymerization and served as chemical crosslinking points to form the Me-PANI NPs@PAM hydrogel, endowing the hydrogel with controllable photothermal antibacterial abilities upon NIR irradiation without time and space limit. Importantly, due to the energy dissipation of Me-PANI NPs under stretch, the Me-PANI NPs@PAM hydrogel achieves a maximum stretching ratio of 400% mechanical flexibility. The developed hydrogel can be potentially applied as a novel wound dressing to realize controllable treatment of bacterial infections and accelerate skin wound healing.