Author: Coviello, T.; Matricardi, P.; Marianecci, C.; Alhaique, F.
Hydrogels are three-dimensional, hydrophilic, polymeric networks, with chemical or physical cross-links, capable of imbibing large amounts of water or biological fluids. Among the numerous macromolecules that can be used for hydrogel formation, polysaccharides are extremely advantageous compared to synthetic polymers being widely present in living organisms and often being produced by recombinant DNA techniques, Polysaccharides are usually non-toxic, biocompatible and show a number of peculiar physico-chemical properties that make them suitable for different applications in drug delivery systems, techniques used for the hydrogel network preparation, on the drug delivery results, on clinical applications as well as on the possible use of such systems as scaffolds for tissue engineering, hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluid, These networks can be classified into two main categories according to the type of cross-linking among the macromolecules, whether chemically or physically based, however, it should be pointed out that both chemical and physical cross-links can occur in the same hydrogel network, In their ability to retain a significant amount of water, hydrogels are quite similar to natural living tissues, rendering them useful for a wide variety of biomedical applications, use of hydrogels as matrices for the encapsulation of living cells, as biologically friendly scaffolds for tissue engineering and for the controlled release of proteins, hydrogels suitable as delivery systems, formulation of modified release dosage forms and devices
