Aspects of three types of hydrogels for biomedical applications

Abstract Some of the chemical and physical properties of three different hydrogels are analyzed as they relate to biological compatibility. The importance of the permeability and diffusion coefficients, porosity, and the possible role of quasiorganized water within the hydrogels are emphasized. It is suggested that the biological environment with its dissolved components such as ions, proteins, carbohydrates, lipids, and enzymes will influence the ultimate biological performance of hydrogels. This biological performance will depend not only on the hydrophilicity of the system but on numerous other parameters including the chemical composition, types and number of crosslinks, presence of functional groups, quasi‐organized water structure, porosity, and the thermodynamic interaction parameters between the components of the biological environment and the gel. It is suggested that the presence of anionic gorups on certain synthetic hydrogel surfaces may be not essential for blood compatibility, provided that such materials are carefully distinguished from other hydrophilic gels.