Application of self-healing hydrogels for sports injury prevention and rehabilitation

Abstract

BACKGROUND: Self-healing hydrogel, as a novel smart material, has attracted much attention in sports medicine and rehabilitation engineering due to its high water content, favorable biocompatibility, tailorable mechanical properties, and intrinsic ability to self-heal after damage. OBJECTIVE: To systematically review the progress of self-healing hydrogels in the prevention, treatment, and rehabilitation of sports injuries. METHODS: A search was conducted on authoritative domestic and international databases including CNKI, X-mol, and PubMed. Research literature involving self-healing hydrogels and sports medicine was selected. English and Chinese search terms included "self-healing hydrogel, sports injury repair, activity monitoring, smart rehabilitation, wearable sensors." Based on inclusion criteria, 136 articles were finally included in this review. RESULTS AND CONCLUSION: Self-healing hydrogels show significant advantages in the repair of ligaments, tendons, cartilage, and bone tissue, providing essential mechanical support and promoting cell adhesion, proliferation, and differentiation. By controlling the release of drugs or growth factors, they achieve anti-inflammatory, analgesic, and accelerated tissue regeneration effects. In the fields of motion monitoring and rehabilitation, self-healing hydrogels serve as core components of flexible sensors for real-time monitoring of movement posture and joint stress, and can be integrated with virtual reality, augmented reality, and telemedicine platforms to promote intelligent and precise rehabilitation training. Self-healing hydrogels are evolving toward functional integration, extending beyond simple material repair to a synergistic platform integrating monitoring, treatment, and rehabilitation. Despite significant progress in recent years, challenges remain in mechanical durability, rapid healing efficiency, scalable preparation, and clinical translation. Future research should focus on optimizing high-strength, multi-stimuli-responsive hydrogel designs, deepening the integration of sports biomechanics and artificial intelligence, constructing data-driven personalized rehabilitation models, and promoting interdisciplinary collaboration and establishment of testing standards, to provide more scientific and standardized solutions for the prevention, intervention, and rehabilitation of sports injuries.

1. Introduction

With the high-intensity development of competitive sports and the popularity of public fitness, the incidence of sports-related injuries has increased year by year, especially acute injuries and chronic strains in high-load areas such as the knee, ankle, and shoulder joints, which have become important issues affecting athletes' performance and the general population's participation in sports [1-5]. Traditional treatment methods such as surgical repair, drug intervention, and rehabilitation training can restore function to some extent, but they have shortcomings in mechanical matching, long-term stability, and individualized rehabilitation [6-10]. Therefore, there is an urgent need for new intelligent materials to break through traditional limitations and improve the efficiency and precision of sports injury prevention and rehabilitation [11-12]. Self-healing hydrogels, as a rapidly developing intelligent soft material in recent years, provide a new opportunity to solve this problem [13].

Self-healing materials generally refer to material systems that can autonomously repair damage and restore their structure and performance without external intervention [14]. According to different repair mechanisms, self-healing properties can be further divided into "self-repair" and "self-recovery" categories: the former emphasizes that the material can re-adhere at the macroscopic level to restore overall shape, such as hydrogels recombining into a complete structure after being cut; the latter repairs internal damage through processes such as molecular diffusion, chain entanglement, or recombination of ionic bonds, restoring its viscoelasticity and three-dimensional network structure. These properties endow self-healing hydrogels with unique advantages in resisting crack propagation, extending service life, and improving service reliability [15-16].

Inspired by nature's "self-healing" phenomena, researchers have introduced physical cross-linking to endow synthetic polymer hydrogels with autonomous healing functions. For example, pH-responsive polymer hydrogels developed by mimicking blue mussel secretions can rapidly repair in physiological environments; hydrogels loaded with healing agents or embedded with three-dimensional vascular-like networks mimic skin tissue regeneration [17-21]. Hydrogels have high water content, tunable network structure, and good biocompatibility, and have been widely used in wound dressings, contact lenses, tissue engineering scaffolds, and drug delivery [15,22-28]. However, traditional hydrogels often exhibit brittleness and low toughness, with fracture energy typically less than 10 J·m-2 [29], far below the high toughness of articular cartilage (≈1,000 J·m-2) and strength (up to 30 MPa) [30-31]. In application scenarios such as sports injury repair and exercise loading, traditional hydrogels often have insufficient mechanical adaptability. To address this limitation, researchers have introduced sacrificial bonds, composite or hybrid structures, and interpenetrating polymer networks into hydrogel networks, significantly enhancing energy dissipation and overall toughness. This series of improvements has promoted the continuous development of "high-toughness self-healing hydrogels" [32-35]. Such materials can not only withstand relatively large deformations but also combine with...