Hydrogels ionic interactions

Poly(L-lysine)-based hydrogel Ionic interaction pH [20]... 

Fig. 1 Representative methods of hydrogel formation. (A) Chemically cross-linked hydrogels are prepared from monomers, oligomers, or polymers in the presence of cross-linking agents. The chemical cross-linking proceeds via radical polymerization or polycondensation reaction. (B) Physically cross-linked hydrogels can be formed by ionic interactions, hydrophobic interaction, or hydrogen bonding.

Figure 20.10. Amphiphilic ionic self-complementary peptides. This class of peptides has 16 amino acids, c. 5 nm in size, with an alternating polar and non-polar pattern. They form stable (3-strand and 3-sheet structures thus, the side chains partition into two sides, one polar and the other non-polar. They undergo self-assembly to form nanofibers with the non-polar residues inside positively and negatively charged residues form complementary ionic interactions, like a checkerboard. These nanofibers form interwoven matrices that further form a scaffold hydrogel with a very high water content ( 99.5%). The simplest peptide scaffold may form compartments to separate molecules into localized places where they can not only have high concentration, but also form a molecular gradient, one of the key prerequisites for prebiotic molecular evolution.

De Boisseson, M.R., Leonard, M., Hubert, P., Marchal, P., Stequert, A., Castel, C., Favre, E., Dellacherie, E. Physical alginate hydrogels based on hydrophobic or dual hydrophobic/ ionic interactions Bead formation, structure, and stability. J. Colloid Interface Sci. 273, 131-139 (2004)... 

Figure 30 High water-content moldable hydrogels made from clay-organic composites driven by noncovalent ionic interactions. Reproduced from...

Some hydrogels are formed by physical interactions between pol)iner chains. These interactions include hydrogen bonding, hydrophobic interactions, and ionic interactions. Several types of physical gels are listed in Table 1. 

Thermoreversible supiamolecular 2006 [47] assembly fast gelation and slow dissociation intetmolecular ionic interactions stimuli-sensitive hydrogels... 

Hydrogels have been synthesized based on both chemical (covalent bonds between polymer chains) and physical crosslinking (e.g., polymer chain entanglements, ionic interactions, and hydrogen bonds) methods (Hoffman, 2002) (Figure 1.5). Covalently crosslinked thermo-responsive hydrogels exhibit reversible swelling of the crosslinked... 

Park, M.-R., Seo, B.-B. and Song, S.-C. (2013). Dual ionic interaction system based on polyelectrolyte complex and ionic, injectable, and thermosensitive hydrogel for sustained release of human growth hormone. Biomaterials, 34,1327-1336. 

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