Introduction

Hydrogels, three-dimensional networks of cross-linked polymers, have garnered significant attention in recent years due to their tunable properties and diverse applications. This mini-review focuses on advancements in hydrogel research over the past five years (2020-2024), based on the provided literature. We will explore progress in three key areas: enhancing mechanical properties, developing advanced wound healing applications, and creating novel hydrogel-based sensors.

Enhanced Mechanical Properties of Hydrogels

A significant area of hydrogel research focuses on improving their mechanical properties, such as toughness, stretchability, and self-healing capabilities. Researchers have explored various strategies to achieve these enhancements.

One approach involves creating double-network (DN) hydrogels. Yilong Cheng's research group demonstrated that toughening DN hydrogels can be achieved by incorporating polyelectrolytes (Mengyuan Zhang et al., 2023, Advanced Materials). Xinling Wang's group further refined this approach, developing tough DN hydrogels with rapid self-reinforcement and low hysteresis by utilizing highly entangled networks (Zhu Ruixin et al., 2024, Nature Communications).

Another strategy involves incorporating nanofillers, such as cellulose nanofibrils (CNFs) and MXenes, to reinforce the hydrogel matrix. Feng Jiang's group has shown the potential of CNFs in enhancing hydrogel properties, demonstrating a "salting out-alignment-locking" tactic to create strong and tough hydrogels (Xia Sun et al., 2024, Advanced Materials). Long-Cheng Tang's group explored the use of quaternized CNFs and MXenes to create conductive hydrogels for flexible strain sensors (Qing-Yue Ni et al., 2024, Journal of Material Science and Technology). Chaoji Chen's group has also demonstrated the use of cellulose-bentonite coordination interactions to create strong, tough, ionic conductive, and freezing-tolerant all-natural hydrogels (Siheng Wang et al., 2022, Nature Communications).

Zhigang Suo's group investigated the fundamental relationship between polymer entanglements and mechanical properties, revealing insights into fracture, fatigue, and friction in polymers with a high entanglement density (Junsoo Kim et al., 2020, Science; Junsoo Kim et al., 2021, Science). Chao Wang's group recently developed a hyperelastic hydrogel exhibiting an ultralarge reversible biaxial strain, pushing the boundaries of hydrogel deformability (Lili Chen et al., 2024, Science). Youhui Lin's group has also demonstrated the creation of bioinspired structural hydrogels with highly ordered hierarchical orientations by flow-induced alignment of nanofibrils (Shuihong Zhu et al., 2024, Nature Communications).

Hydrogels for Advanced Wound Healing

Hydrogels have emerged as promising materials for wound healing applications due to their biocompatibility, ability to maintain a moist wound environment, and capacity to deliver therapeutic agents. Recent research has focused on developing multifunctional hydrogels that address various challenges in wound healing, particularly in diabetic and infected wounds.

Baolin Guo's research group has been particularly active in this area, developing a range of advanced hydrogel dressings. These include antibacterial adhesive hydrogels with on-demand removability (Yuqing Liang et al., 2020, ACS Nano; Yuqing Liang et al., 2021, ACS Nano), physical double-network hydrogel adhesives with self-healing and antioxidant properties (Xin Zhao et al., 2020, Advanced Functional Materials), pH/glucose dual-responsive hydrogels for diabetic foot wound healing (Yongping Liang et al., 2020, ACS Nano; Yongping Liang et al., 2021, ACS Nano; Yongping Liang et al., 2022, ACS Nano), conductive adhesive self-healing hydrogels for photothermal therapy (Jiahui He et al., 2020, Chemical Engineering Journal), mussel-inspired adhesive antioxidant antibacterial hemostatic composite hydrogels (Yutong Yang et al., 2021, Bioactive Materials), antibacterial adhesive self-healing hydrogels for diabetic wound healing (Jueying Chen et al., 2022, Acta Biomaterialia), bacteria-induced tobramycin releasing self-healing hydrogels for infected burn wound healing (Ying Huang et al., 2022, ACS Nano), antibacterial conductive self-healing hydrogel wound dressings (Lipeng Qiao et al., 2023, Bioactive Materials), physical dynamic double-network hydrogels as dressings to facilitate tissue repair (Baolin Guo et al., 2023, Nature Protocols), and bacteria-responsive programmed self-activating antibacterial hydrogels (Yutong Yang et al., 2024, National Science Review).

Other research groups have also contributed significantly to this area. Xiaojun He's group developed immunoregulatory hydrogels for diabetic wound repair using photoenhanced glycyrrhizic acid (Yuna Qian et al., 2021, Advanced Materials; Yuna Qian et al., 2022, Advanced Materials). Chenhui Zhu's group created an artificial nonenzymatic antioxidant MXene nanosheet-anchored injectable hydrogel for diabetic wound healing (Yang Li et al., 2022, ACS Nano). Xing Zhao's group developed an all-natural immunomodulatory bioadhesive hydrogel that promotes angiogenesis and diabetic wound healing by regulating macrophage heterogeneity (Yajun Fu et al., 2023, Advanced Science). Mohammad-Ali Shahbazi's group designed a whole-course-repair system based on neurogenesis-angiogenesis crosstalk and macrophage reprogramming to promote diabetic wound healing (Yuan Xiong et al., 2023, Advanced Materials). Xiaoliang Qi's group engineered melanin-reinforced biopolymer hydrogels for highly efficient bacteria-infected diabetic wound healing (Yajing Xiang et al., 2023, Chemical Engineering Journal). Tao Xiang's group developed a wound microenvironment self-adaptive hydrogel with efficient angiogenesis for promoting diabetic wound healing (Zijian Shao et al., 2022, Bioactive Materials). Juan Ye's group created a tough, antibacterial, and antioxidant hydrogel dressing that accelerates wound healing and suppresses hypertrophic scar formation in infected wounds (Xiaoqing Liu et al., 2024, Bioactive Materials). Bing Liu's group developed a programmed microalgae-gel that promotes chronic wound healing in diabetes (Yong Kang et al., 2024, Nature Communications). Mary B. Chan-Park's group created hydrogel dressings with intrinsic antibiofilm and antioxidative dual functionalities that accelerate infected diabetic wound healing (Dicky Pranantyo et al., 2024, Nature Communications).

Hydrogels for Sensing Applications

The development of hydrogel-based sensors has also seen significant advancements. These sensors leverage the unique properties of hydrogels, such as their flexibility, stretchability, and sensitivity to various stimuli, for applications in wearable electronics, biomedical monitoring, and environmental sensing.

Guodong Li's group developed conductive hydrogels for fabricating flexible strain sensors (Gang Li et al., 2021, Small). Pengbo Wan's group created healable, degradable, and conductive MXene nanocomposite hydrogels for multifunctional epidermal sensors (Xiaobin Li et al., 2021, ACS Nano). Sufeng Zhang's group developed super stretchable, self-healing, adhesive ionic conductive hydrogels for high-performance strain sensors (Xue Yao et al., 2022, Advanced Functional Materials). Guoying Gu's group created high-stretchability, ultralow-hysteresis conducting polymer hydrogel strain sensors for soft machines (Zequn Shen et al., 2022, Advanced Materials). Chuan Fei Guo's group developed highly conducting and stretchable double-network hydrogels for soft bioelectronics (Gang Li et al., 2022, Advanced Materials). Wentao Liu's group created highly sensitive and robust polysaccharide-based composite hydrogel sensors with underwater repeatable self-adhesion and rapid self-healing for human motion detection (Qiangjun Ling et al., 2022, ACS Applied Materials & Interfaces). Xin Jing's group developed multifunctional organohydrogels with ultralow-hysteresis, ultrafast-response, and whole-strain-range linearity for self-powered sensors (Jian Zou et al., 2023, Advanced Functional Materials). Dan Yang's group created self-adhesive, self-healing, biocompatible and conductive polyacrylamide nanocomposite hydrogels for reliable strain and pressure sensors (Yongji Li et al., 2023, Nano Energy). Ning Hu's group engineered smart composite hydrogels for wearable disease monitoring (Jianye Li et al., 2023, Nano-Micro Letters). Haibin Gu's group developed collagen-based organohydrogel strain sensors with self-healing and adhesive properties for detecting human motion (Qiangjun Ling et al., 2023, ACS Applied Materials & Interfaces). Chunya Wang's group created a 10-micrometer-thick nanomesh-reinforced gas-permeable hydrogel skin sensor for long-term electrophysiological monitoring (Zongman Zhang et al., 2024, Science Advances). Maolin Yu's group developed MXene hybrid conductive hydrogels with mechanical flexibility, frost-resistance, and photothermoelectric conversion characteristics for multiple sensing applications (Mengjuan Hou et al., 2024, Chemical Engineering Journal). Yiying Yue's group developed nanocellulose-mediated conductive hydrogels with NIR photoresponse and fatigue resistance for multifunctional wearable sensors (Chenyu Sang et al., 2024, Carbohydrate Polymers) and nanocellulose-mediated bilayer hydrogel actuators with thermo-responsive, shape memory and self-sensing performances (Yuanyuan Ma et al., 2024, Carbohydrate Polymers). Weizheng Li's group demonstrated stretch-induced conductivity enhancement in highly conductive and tough hydrogels (Xiaowei Wang et al., 2024, Advanced Materials). Chaoji Chen's group also developed cellulose nanofiber-mediated manifold dynamic synergy enabling adhesive and photo-detachable hydrogel for self-powered E-skin (Lei Zhang et al., 2024, Nature Communications).

Conclusion

The past five years have witnessed significant progress in hydrogel research, particularly in enhancing mechanical properties, developing advanced wound healing applications, and creating novel hydrogel-based sensors. These advancements are driven by innovative material design, a deeper understanding of structure-property relationships, and the integration of hydrogels with other functional materials. While significant strides have been made, further research is needed to address remaining challenges, such as improving long-term stability, biocompatibility, and scalability for widespread adoption in various applications.

✨ About This POST
This mini-review post was generated through Scinapse. Scinapse provides reliable research trend analysis using citation analysis and AI technology.
Check out the trends in your field too!
Get started at https://scinapse.io