Low-degree oxidized scleroglucan and its hydrogel.

A controlled oxidation of scleroglucan was performed with sodium periodate to prepare aldehyde derivatives (scleraldehyde) with a low degree of oxidation (10 and 20%), which were utilized for crosslinking reactions with hexamethylenediamine. The structural characterization of scleraldehydes and their corresponding hydrogels was attempted by small-angle X-ray scattering (SAXS). While scleraldehyde with a higher degree of oxidation (> or = 50%), according to an earlier research, was found to disentangle into single chains as the degree of oxidation increases; scleroglucan bearing a low percentage of aldehydic groups (up to 20%) retains mainly the conformation of the natural polysaccharide, thus the system can be represented as composed of triple helices with only minor disentanglements at the sites where the aldehyde groups are present. The hydrogel prepared from scleraldehyde with a low degree of oxidation is brittle and fragmented, in contrast to the elastic/homogeneous hydrogel earlier prepared from scleraldehyde with a high degree of oxidation. The hydrogel from scleraldehyde with a low degree of oxidation was found to possess a network structure that consisted mostly of the triple helices crosslinked in specific points where the triple helices are disentangled into single chains because of the presence of the aldehyde groups.