Acid-Base Properties and Biological Activity of Starch Phosphate Microgels

Abstract—The apparent ionization constants have been determined for phosphate groups of phosphorylated starch microgels with particle sizes of 300–500 µm. It has been shown that hydrogen bonds formed by phosphate and carbamate groups play an essential role in the acid-base equilibrium of starch phosphorylated in an orthophosphoric acid−urea system. It has been found that the acidic properties of starch phosphate microgels are almost independent of the ionic strength of a solution (0.05–0.5) and the concentration of phosphate groups (2.0–3.8 mmol/g). The cytostatic activity of starch phosphate microgels has been revealed in vitro using the HeLa cell culture.