Hydrogel-based drug delivery systems - a review

Hydrogels are unique polymer materials that possess hydrophilic chains, allowing them to effectively retain a considerable amount of water within their interstitial structures. The first hydrogel, developed in 1955 by Professor Lim and Wichterle from Prague, was specifically designed for manufacturing contact lenses. Hydrogel has the unique ability to absorb and retain a significant amount of water without dissolving. These gels consist of a three-dimensional (3D) network structure composed of cross-linked polymers. Hydrogels can undergo changes in their properties or behavior in response to different stimuli. There are two main problems addressed when using hydrogels: Firstly, it is imperative to conduct more in vivo research and how they behave after being implanted in humans. Secondly, it's crucial to create new, effective, and ecologically responsible ways to make hydrogels. Hydrogels have emerged as unparalleled vehicles for drug delivery, particularly in the context of brain or spinal cord lesions, heavy metal removal, tissue engineering, biosensor, regeneration, cancer, bioprinting, soft robots, biosensor, photonics, perfumery and food industry. In the future, it will be profitable to focus on the development of more sophisticated biopolymer-based hydrogels, combining natural polymers with elastin-cellulose and elastin-alginate mixes. Such developments would be very helpful in tissue regeneration.