Advances in natural polymer-based hydrogels: synthesis, applications, and future directions in biomedical and environmental fields

Hydrogels, with their remarkable biocompatibility, biodegradability, and versatility, have garnered immense attention across biomedical and industrial landscapes. Among the diverse categories of hydrogels, those derived from natural polymers have risen to prominence, owing to their inherent biocompatibility and environmental sustainability. This review meticulously explores the forefront of innovations in the synthesis and applications of natural polymer-based hydrogels. Key natural polymers such as starch, chitosan, alginate, lignin, and carrageenan are scrutinized for their unique structural properties, gelation mechanisms, and the profound influence of crosslinking agents on their performance. The versatile applications of these hydrogels in domains like tissue engineering, controlled drug delivery, wound healing, and environmental remediation are critically evaluated. Particular emphasis is placed on overcoming challenges related to mechanical robustness, tuning degradation rates, and scaling production for broader applicability. By delving into these aspects, this review highlights the field's cutting-edge progress and illuminates the transformative potential of natural polymer hydrogels to address pressing biomedical and ecological challenges. Through this comprehensive synthesis of current advancements and emerging trends, the review aspires to inspire future research and innovation in harnessing the full potential of these sustainable biomaterials.