Time and temperature dependent aggregation behaviour of the ganglioside GM1 in aqueous solution.

Gangliosides are marked amphiphiles with several ramified sugar rings and a ceramide moiety. Therefore they form micelles in aqueous solution. This aggregation behavior is studied with static and dynamic light scattering and small angle X-ray scattering. The shape and the size of the GM1 micelles in dependence of time and temperature are investigated. Some data have been published recently where two stable states for the micelles are found. This bistability is said to be achieved by temperature rise from room temperature up to 55 degrees C. The authors did not find such an internal structural change of the micelle in the experiments. Instead the authors found some large aggregates of the ganglioside in parallel to the micelle caused by the low solubility of this system at room temperature. These aggregates are dissolved quickly with increasing temperature or slowly with time at room temperature. So the variation of the scattering intensity is explainable by dissolving the large particles, meanwhile the structure of the GM1 micelles is the same all the time.