Preparation and Characterization of Partially Oxidized Sodium Alginate

Sodium alginate has been widely used in a variety of biomedical applications.However,alginate(itself) has a very slow degradation rate,and its gels degrade in an uncontrollable manner,releasing high(molecular) weight strands that are difficult to drain from the body.In order to improve the biodegradability of alginate,commercially available high molecular weight alginate was oxidized with sodium periodate.The IR(analysis) confirmed the characteristic peak of aldehyde group in the oxidized alginate.Oxidized alginate fully degraded at physiological condition(37 ℃,pH=7.4 PBS) after 100 h incubation and the molecular weight reduced from 11.2×10~(4) g/mol to 3.6×10~(4) g/mol.When small amounts of uronate groups were oxidized,the aqueous solution of the oxidized alginates still formed hydrogels in the presence of calcium ions in a manner similar to that of native sodium alginate.However,the compressive strengths of these hydrogels were lower than those of unmodified alginate and decreased quickly with incubation time.