Polysaccharides, such as alginates, are already being used as carriers for drug delivery. The physicochemical and
biological properties of alginates may be affected via irradiation and thermal treatments. To explore and compare effects of
two kinds of sterilization methods, gamma irradiation and moist heat, on sodium alginate (SA), physicochemical and biological
properties of SA powder and solutions were investigated after sterilization. Human umbilical vein endothelial cells (HUVEC)
was used to assess the cytotoxicity of the SA after sterilization. The research showed that 25 kGy gamma ray can effectively
sterilize microorganism. Both gamma irradiation and moist heat hardly affect the native pH of SA. Compared to irradiation
sterilization, moist heat sterilization showed smaller changes in intrinsic viscosity for all SA samples and lead to less glycosidic
bond breaking of SA powders. The moist heat sterilization can cause the main chain scission and double bonds formation of the
SA solutions. Cytotoxicity studies demonstrated that sterilized SA powers and SA solutions treated by gamma ray sterilization
can increase the viability of HUVEC. However, SA solutions treated by moist heat sterilization were found to present severe
cytotoxicity. The research results may provide interesting future advancements toward the development of SA-based products
for biomedical applications.