The Effect of Heparin and Peptide Conjugation on the Structure and Properties of Polysaccharides in Solutions and Hydrogels

Cells are able to produce their native ECM and self-organize into complex tissues as long as their native microenvironment is duplicated in vitro. Therefore, multifunctional biomimetic matrices that can serve as adaptive networks and perform each of the ECM`s different roles simultaneously are required for successful tissue regeneration. Much effort in creating such networks has focused on incorporating biological features (such as peptides or proteins) within synthetic scaffolds.

Among various scaffold materials that have been investigated, hydrogels remain the most appealing candidates due to their structural similarity to the natural ECM. Hydrogels composed of natural polymers, such as polysaccharides (e.g. Alginate), are especially attractive, as they have a large variety of compositions and properties that cannot be easily mimicked in a laboratory. Since polymeric networks containing multiple polysaccharides may better mimic the complicated environment of the ECM, the addition of heparin and peptide (e.g. G₄RGDY), a polysaccharide with attractive biological properties, to Alginate hydrogels seems highly promising.

Thorough characterization of these hydrogels, in all aspects, will enable the development of specifically tailored materials for use in different applications.

Apart from its direct role in cell interaction, the addition of heparin and peptide may also impact the hierarchical structural organization of a surrogate ECM, allowing for changes in physical and mechanical properties. The focus of this project is to fully characterize the effect that covalently binding of heparin and peptide can have on solution and gels of Alginate using several techniques- Fourier transform infrared spectroscopy (FTIR), rheology and small angle x-ray scattering (SAXS).

Results show that incorporation of both heparin and RGD peptide had a synergetic effect on the alginate rheological properties and that the order of conjugation plays a major role in determining these properties.