Modeling of molecular weight changes of polysaccharides subjected to irradiation

Irradiation is widely used for the sterilization of biomaterials and is known to lead to a decrease in the molecular weight of polysaccharides. However, the quantitative relationship between irradiation parameters and polysaccharide molecular weight reduction remains poorly defined. In this study, the molecular weights of hyaluronic acid (HA) with different initial chain lengths were evaluated after ultraviolet, gamma ray and electron beam irradiation, to establish and verify a mathematical model to predict polysaccharide degradation. It was found that the molecular weight of HA decreases inversely with irradiation time or dose (R-squared: 0.71 - 0.96). Based on these data, a quantitative model was developed to predict the molecular weight of HA after irradiation sterilization, and its feasibility was validated through both theoretical analysis and experimental verification. Besides HA powders, this quantitative model also applies to HA solutions and other polysaccharides (alginate and dextran). To our knowledge, this is the first study to propose a predictive model for molecular weight changes of polysaccharides exposed to irradiation. It could potentially reduce the mis-estimation of polysaccharide properties, especially that influenced by molecular weight, such as degradation and viscoelasticity.