Quazi Mohzibudin Z, Quazi Aaquib Saeed, Song Youngseo, Park Nokyoung
Department of Chemistry and The Natural Science Research Institute, Myongji University, Myongji-ro, Yongin 17058, Gyeonggi-do, Republic of Korea.
Department of Biochemistry, Government Medical College and Hospital, Jalgaon 425001, MH, India.
Int J Mol Sci. 2025 Sep 17;26(18):9066. doi: 10.3390/ijms26189066.
Functional hydrogels are a growing class of soft materials. Functional hydrogels are characterized by their three-dimensional (3D) polymeric network and high water-retention capacity. Functional hydrogels are deliberately engineered with specific chemical groups, stimuli-responsive motifs, or crosslinking strategies that impart targeted biomedical or environmental roles (e.g., drug delivery, pollutant removal). Their capacity to imitate the extracellular matrix, and their biocompatibility and customizable physicochemical properties make them highly suitable for biomedical and environmental applications. In contrast, non-functional hydrogels are defined as passive polymer networks that primarily serve as water-swollen matrices without such application-oriented modifications. Recent progress includes stimuli-responsive hydrogel designs. Stimuli such as pH, temperature, enzymes, light, etc., enable controlled drug delivery and targeted therapy. Moreover, hydrogels have shown great potential in tissue engineering and regenerative medicine. The flexibility and biofunctionality of hydrogels improve cell adhesion and tissue integration. Functional hydrogels are being explored for water purification by heavy metal ion removal and pollutant detection. The surface functionalities of hydrogels have shown selective binding and adsorption, along with porous structures that make them effective for environmental remediation. However, hydrogels have long been postulated as potential candidates to be used in clinical advancements. The first reported clinical trial was in the 1980s; however, their exploration in the last two decades has still struggled to achieve positive results. In this review, we discuss the rational hydrogel designs, synthesis techniques, application-specific performance, and the hydrogel-based materials being used in ongoing clinical trials (FDA-approved) and their mechanism of action. We also elaborate on the key challenges remaining, such as biocompatibility, mechanical stability, scalability, and future directions, to unlocking their multifunctionality and responsiveness.
功能性水凝胶是一类不断发展的软材料。功能性水凝胶的特点是具有三维（3D）聚合物网络和高保水能力。功能性水凝胶是通过特定的化学基团、刺激响应基序或交联策略精心设计而成的，这些赋予了其特定的生物医学或环境功能（如药物递送、污染物去除）。它们模仿细胞外基质的能力、生物相容性和可定制的物理化学性质使其非常适合生物医学和环境应用。相比之下，非功能性水凝胶被定义为主要作为水溶胀基质的被动聚合物网络，没有这种面向应用的修饰。最近的进展包括刺激响应性水凝胶设计。诸如pH值、温度、酶、光等刺激能够实现可控药物递送和靶向治疗。此外，水凝胶在组织工程和再生医学中显示出巨大潜力。水凝胶的柔韧性和生物功能性改善了细胞黏附和组织整合。正在探索功能性水凝胶用于通过去除重金属离子和检测污染物来进行水净化。水凝胶的表面功能已显示出选择性结合和吸附，以及使其对环境修复有效的多孔结构。然而，长期以来水凝胶一直被认为是临床进展中潜在的候选材料。首次报道的临床试验是在20世纪80年代；然而，在过去二十年中对它们的探索仍难以取得积极成果。在这篇综述中，我们讨论了合理的水凝胶设计、合成技术、特定应用性能，以及正在进行的临床试验（FDA批准）中使用的基于水凝胶的材料及其作用机制。我们还阐述了仍然存在的关键挑战，如生物相容性、机械稳定性、可扩展性以及未来方向，以释放它们的多功能性和响应性。
