Abstract: O-quaternized thiourea oligosaccharides was prepared with chitosan oligosaccharides as raw materials, and its structure was characterized by infrared spectrum (IR), UVVis absorption spectra and thermogravimetric analysisdifferential thermal analysis (TG-DTA) methods. Using the herring sperm DNA as a target, the action mode of O-quaternized thiourea oligosaccharides and herring sperm DNA was studied by UV-Vis absorption spectra, cyclic voltammetry (CV) and viscosity method. The experimental results show that the absorption peak of Oquaternized thiourea oligosaccharides appears at 213.5 nm and 280.0 nm, its thermal stability is poor, and the oxygenolysis begins at 180 ℃. The UVVis absorption peaks of Oquaternized thiourea oligosaccharides change after adding DNA, O-quaternized thiourea oligosaccharides reduce the current of the redox peak of the potassium ferricyanideDNA system, potential shifts positively, and the viscosity of DNA increases. The action mode of O-quaternized thiourea oligosaccharides and DNA is intercalation.

Key words: chitooligosaccharide, quaternization, herring sperm DNA, thiourea