ABSTRACT
Natural hydrogels from the biomass include collagen, fibrin, hyaluronic acid, matrigel, and derivatives of natural materials such as chitosan, alginate, and fibers of silk. In order to fit the new requirements and properties for different applications, smart hydrogel systems, with various chemically and structurally responsive moieties, were synthesized. In the technological field, the biopolymer-based hydrogels such as chitosan, alginate, starch, and cellulose were used to remove heavy metal ions from aqueous media. Thermosensitive hydrogels have been widely investigated for their adjustable swelling properties in response to temperature changes, leading to on-demand modulation of drug release from the gels. The pH plays an important role in different processes such as preparation, purification, hydrogel device formation, swelling, release, and degradation rate. In the search of new anticoagulants, I. Freeman et al. sulfated the uronic acids alginate and hydrogels of mixed alginate/alginate–sulfate were manufactured.
