Eco-hydrogels: The new frontier of sustainability: A review

The growing demand for eco-friendly materials to address environmental, economic, and health challenges is rapidly shifting the focus of materials science toward natural and bio-based alternatives. Among these, eco-hydrogels have emerged as a promising class of materials due to their biodegradability, non-toxicity, and renewable origin. This review goes beyond a mere summary of the literature by critically analyzing the sustainability potential of natural hydrogels compared to synthetic counterparts. We identify key knowledge gaps that hinder their large-scale application, including poor mechanical stability, lack of standardized green metrics, and limited scalability of production methods. Furthermore, we propose strategic directions to overcome these limitations, such as hybrid formulations, bio-inspired crosslinking, and lifecycle-based assessment tools. By mapping current progress and critical bottlenecks, this work aims to guide future research toward the development of next-generation hydrogels that are not only high-performing, but also environmentally sustainable. • Sustainability-centered classification : The review introduces a novel hydrogel classification system that prioritizes green chemistry and environmental impact. • Strategic research directions proposed : It outlines practical strategies to overcome eco-hydrogel limitations. • Critical gaps in current literature : The paper emphasizes both sustainability and economy impacts. • Emerging green technologies : It highlights green innovations such as NADES, enzymatic crosslinking, and mechanochemical synthesis methods • Real-world application challenges : The review highlights eco-hydrogels limitations including mechanical weakness and scale up challenges—while guiding future research.