Abstract: In order to determine the effect of ultrasonic treatment on the fibril formation and physicochemical properties of collagen from Carassius auratus skin, the self-assembly kinetics, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern, fluorescence spectra, circular dichroism spectra, fibrillar morphology and NIH/3T3 cell proliferation ability of the collagens with and without ultrasonic treatment were analyzed and compared. The results showed that the nucleation phase of collagen self-assembly was significantly shortened and the fibril formation rate was increased after ultrasonic treatment at 100–200 W for 1–10 min. When the ultrasonic power was 600 W or the ultrasonic time was longer than 10 min, the collagen subunit was degraded, and its characteristics as type I collagen were weakened. After sonication, the ratio of positive to negative Cotton effect (RPN) of collagen from Carassius auratus skin showed a downward trend, and its fluorescence intensity was increased remarkably, with about 3 nm blue shift being observed in the maximum emission wavelength. In addition, the collagen showed a large number of pores and loose cross-sections and its fibers were uniform in morphology after ultrasonic treatment. The results of cell proliferation test showed that ultrasonic treatment in the power range of 100–200 W for 1–10 min could significantly improve the NIH/3T3 cell proliferation capacity of collagen from Carassius auratus skin (P < 0.05). After ultrasonic treatment at 200 W for 1 min, the NIH/3T3 cell proliferation capacity of the collagen was increased by 10.1%. In conclusion, moderate sonication can promote the self-assembly process of collagen from Carassius auratus skin, and effectively improve its structure and physicochemical properties. This study suggests that ultrasonic treatment is an effective modification method for collagen from Carassius auratus skin.

Key words: ultrasonic treatment; Carassius auratus; collagen; self-assembly; physicochemical properties