Q-dextran 4 (QD4)
Q-dextrans 4 only contain quaternary amine groups and unlike DEAE-dextrans, Q-dextrans will be charged over the normal range of use for dextrans (pH 4-10). The nitrogen content is approx. 2% (by elemental analysis) which corresponds to approximately one quaternary ammonium group for every four glucose units. These derivatives are very soluble in water and are supplied as white powders. It can be inferred from the molecular weight determinations (GPC), that the hydrodynamic volumes of Q-dextrans do not differ greatly from dextran itself. These products will have a much stronger net charge than corresponding DEAE-dextrans and thus give enhanced responses in systems where this effect is important. Polycationic products exhibit a wide variety of effects in cellular systems and are of interest as adjuvants in vaccines.