Nanocellulose-based hydrogels for smart sensors

With the rapid development of smart sensor technology, there is a growing demand for high-performance sensing materials. However, the shortcomings of traditional hydrogels in terms of performance and stability limit their application in the field of high-end smart sensors. Nanocellulose, as a novel biomass material, stands out due to its renewability and the abundant hydroxyl functional groups on the surface that facilitate chemical modification. This not only brings new ideas for the optimization of hydrogel properties, but also provides a broad space for the expansion of hydrogel applications. Here, this review comprehensively summarizes the research progress of nanocellulose-based hydrogels in the field of sensing, and provides an in-depth analysis of the unique advantages of nanocellulose in hydrogel sensors, including tunable mechanical properties, excellent resistance to water loss, and self-healing properties. In addition, the article discusses in detail the key regulatory strategies and functionalization methods of nanocellulose-based hydrogels. Subsequently, it focuses on the progress of research and application of nanocellulose-based hydrogel in multiple areas of physical sensors (strain/pressure), chemical sensors (ion, gas, pH), and biosensors (urea, lactate, glucose). Finally, the future development of nanocellulose-based hydrogels in the field of smart sensors is envisioned.