Biocompatible and Degradable Alginate Hydrogel as a Template for Cell Culture and Molecular Release
Hydrogels are soft and hydrated biomaterials, which are often used for mimicking cell environments in 2D and 3D. With their softness and biocompatibility, these hydrogels are also predestinated material matrixes for drug release purposes for cells in vitro as well as in vivo experiments and can be of great benefit for clinical use. Hydrogel matrices can be prepared from synthetic or natural origins, with physical crosslinking (e.g. in calcium alginate) or with covalent crosslinker. They can be modified in a variety of different ways, e.g. by different types of crosslinker, by varying the degree of crosslinking, or by adapting the microstructure of the hydrogels.
Here, we present our results of a covalently crosslinked alginate hydrogel which can be used as degradable and biocompatible cell culture matrix and as a degradable drug release template. The covalently crosslinked alginate is prepared with carbodiimide chemistry. The carboxyl groups of the alginate and a crosslinker with diamine groups are used and have the advantage of cleavable hydrazine bonds from the crosslinker.
For loading a model drug into the alginate matrix, templates were first dried and then hydrated in a solution containing the desired model drug. In this way we were able to adjust the uptake of the model drug. Next, the release of the model drug in a known volume was investigated. The network densities of the hydrogels used were found to be important for the release. The network densities determine the mechanical properties of the alginates as well as the swelling behavior of the hydrogel scaffolds, the model drug uptake, the material degradation and the release.
Our approach, using biocompatible, degradable and covalently crosslinked alginates enabled us to use degradable drug release templates for future applications in in vitro cell cultures or even in vivo experiments in tissues, where a physical crosslinking by ions would be disadvantageous.
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