Green Fabrication Approach to Hydrogel Synthesis by Using Natural Polymers, their Characterization, and Applications

Background: Cross-linked networks of polymers are referred to as hydrogels because they possess the ability to retain water within the interstitial spaces of the polymer chains. The fundamental building block of life is a polymer. Researchers' interest in polymers has expanded due to the widespread availability of polymers exhibiting desirable characteristics, a key factor in the development of contemporary healthcare products. The synthesis of hydrogels involves the integration of various natural polymers. In the realm of biomedical applications, hydrogels can be employed to deliver drugs or cells, regenerate both hard and soft tissues, adhere to moist tissues, halt bleeding, provide contrast during imaging, shield tissues or organs from radiation, and enhance the biological adaptability of therapeutic implants. These attributes render hydrogels advantageous for a diverse array of distinct and critical diseases and medical scenarios, as well as in less conventional fields such as environmental engineering. Objectives: The primary objective of this review is to explore the literature related to hydrogels. This includes the classification of hydrogels, examination of natural polymers such as collagen, inulin, pectin, alginate, tragacanth, lignin, and chitosan, which are employed in hydrogel synthesis. The review also covers the general preparation of hydrogels, the methodologies involved in their preparation, common techniques used in characterization, release kinetics, and the diverse applications of hydrogels. Conclusion: This research covers the study of natural polymers such as inulin, alginate, lignin, pectin, collagen, chitosan, and tragacanth, employed in the synthesis of hydrogels. The key areas of focus encompass the classification of hydrogels, procedures for hydrogel preparation, various methods for hydrogel characterization, in vitro and in vivo release kinetics of hydrogels, and the application of hydrogels prepared from specific natural polymers across diverse fields.