The word ‘gel’ refers to a wide class of materials displaying a high capability of absorbing and retaining a liquid medium. Hydrogels are defined as a particular type of macromolecular gels, formed via chemical or physical stabilization of the polymer chains into a three- dimensional network, for which the absorbed liquid is water or a water solution. The hydrophilic nature of hydrogels gives them unique properties in terms of biocompatibility, rubbery mechanical properties similar to those of soft tissues, and mild-gelling conditions, that are suitable for drug delivery and cell transplantation strategies. Moreover, the strong sensitivity to certain environmental stimuli, displayed by some hydrogels in terms of reversible swelling/deswelling phase transitions, makes them particularly attractive as smart materials for use in a wide range of applications. In this chapter, we introduce the theory describing the sorption thermodynamics of chemical hydrogels, discussing the relationships between their microstructural parameters and the resulting macroscopic properties. Various approaches to evaluate the most relevant network parameters affecting the hydrogel swelling capability and mechanical stiffness will be discussed. It is worth noting that the same theory, traditionally formulated for chemical hydrogels, might be applied to describe the behaviour of physical hydrogels as well.
Biocompatibility and other properties of hydrogels in regenerative medicine
SANNINO, Alessandro;MADAGHIELE, Marta;
2009-01-01
Abstract
The word ‘gel’ refers to a wide class of materials displaying a high capability of absorbing and retaining a liquid medium. Hydrogels are defined as a particular type of macromolecular gels, formed via chemical or physical stabilization of the polymer chains into a three- dimensional network, for which the absorbed liquid is water or a water solution. The hydrophilic nature of hydrogels gives them unique properties in terms of biocompatibility, rubbery mechanical properties similar to those of soft tissues, and mild-gelling conditions, that are suitable for drug delivery and cell transplantation strategies. Moreover, the strong sensitivity to certain environmental stimuli, displayed by some hydrogels in terms of reversible swelling/deswelling phase transitions, makes them particularly attractive as smart materials for use in a wide range of applications. In this chapter, we introduce the theory describing the sorption thermodynamics of chemical hydrogels, discussing the relationships between their microstructural parameters and the resulting macroscopic properties. Various approaches to evaluate the most relevant network parameters affecting the hydrogel swelling capability and mechanical stiffness will be discussed. It is worth noting that the same theory, traditionally formulated for chemical hydrogels, might be applied to describe the behaviour of physical hydrogels as well.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
