Hydrogels are three-dimensional networks of polymers made of natural or synthetic materials that possess high degree of flexibility because of their high-water contents. Hydrogels also have the desired functionality, reversibility, sterilizability and biocompatibility to meet the requirements of materials and biology. The characteristics and classification of hydrogels depend on their properties, including source, configuration, cross-linking, physical structure, and ionic charge. According to physical structure, hydrogels are divided into amorphous, semi-crystalline, crystalline, and hydrocolloid aggregates. Based on the charges on the bound groups, hydrogels may be cationic, anionic, or neutral. In addition, hydrogels are classified into physically cross-linked (or self-assembled) hydrogels and chemically cross-linked hydrogels according to the cross-linking. Physically cross-linked hydrogels, also known as reversible gels, are relatively easy to produce without the use of cross-linking agents in the synthesis process. These hydrogels can be synthesized by ionic interaction, crystallization, stereocomplex formation, hydrophobized polysaccharides, protein interaction, and hydrogen bond. In chemically cross-linked hydrogels, there are covalent bonds between different polymer chains. The chemical cross-linking is formed by the addition of crosslinkers, polymer-polymer conjugation, and reactions catalyzed by photosensitive agents or enzymes. The networks produced by chemical cross-linking have relatively high mechanical strength, so chemically cross-linked hydrogels are typically stable with relatively long degradation times. Chemically and physically cross-linked hydrogels are prepared from natural and/or synthetic polymers. The use of natural polymers in hydrogel synthesis is advantageous in biomedical applications due to their biocompatibility, biodegradability and nontoxicity. Hydrogels of natural origin are generally obtained from renewable resources, including chitosan, alginate, hyaluronic acid, collagen, and agarose. Synthetic hydrogels are synthesized using synthetic polymers such as polyamides, polycarbonate urethane (PU), and polyethene glycol (PEG). The synthetic polymers are usually hydrophobic and possess strong covalent bonds within their matrix, which allows for higher durability and mechanical strength.
Hydrogels are capable of retaining a large amount of water or biological fluids and are characterized by a soft rubbery consistency similar to living tissues, making them ideal for a variety of applications. They can be applied to pharmaceuticals, biomedical implants, tissue engineering and regenerative medicines, cell culture, biomolecule separation, and barrier materials for devices. In particular, hydrogels mimic salient elements of native extracellular matrices (ECMs) and support cell adhesion, making them an important material for cell culture. In a range of cell culture applications, hydrogels facilitate revealing fundamental phenomena regulating cell behavior and provide tools for the expansion and directed differentiation of various cell types in ways not possible with conventional culture substrates. Amerigo Scientific offers high quality hydrogel products ranging from pre-configured hydrogels to hydrogel components for a vast range of experimental setups and applications.