The formation of micelles, bilayers or vesicles in aqueous solution depends on the structural properties of the surfactant. Vesicles can act as drug delivery systems in many biotechnological applications. To be suitable as a carrier, surfactant vesicle should have high affinity for the biological membranes and high stability under physiological conditions to release its content in a controlled way. Sultaine surfactants are characterized by low irritancy and non denaturizing-protein effect. The aggregation behaviour of a new synthesized sultaine has been studied in buffer solution at pH 7.4. Spontaneously formed vesicles can be observed by optical microscopy (Fig.1). The sultaine transition temperature has been determined by DSC and Nile Red fluorescence. Two critical vesicular concentrations (CVC1 and CVC2) have been fluorimetrically found and two kind of aggregates have been identified and investigated: vesicles above the CVC1 and closely packed aggregates above the CVC2. The sultaine vesicles formed above the CVC1 decreases their stability from 25 to 75°C due to the membrane association promoted at high temperature. Dynamic Laser Light Scattering and fluorescence measurements confirm the presence of larger aggregates above the CVC2 due to the vesicles assembly promoted at high sultaine concentration.
Effect of Concentration and Temperature on Vesicles Formed by a New Sultaine Surfactant
CERICHELLI, GIORGIO;
2011-01-01
Abstract
The formation of micelles, bilayers or vesicles in aqueous solution depends on the structural properties of the surfactant. Vesicles can act as drug delivery systems in many biotechnological applications. To be suitable as a carrier, surfactant vesicle should have high affinity for the biological membranes and high stability under physiological conditions to release its content in a controlled way. Sultaine surfactants are characterized by low irritancy and non denaturizing-protein effect. The aggregation behaviour of a new synthesized sultaine has been studied in buffer solution at pH 7.4. Spontaneously formed vesicles can be observed by optical microscopy (Fig.1). The sultaine transition temperature has been determined by DSC and Nile Red fluorescence. Two critical vesicular concentrations (CVC1 and CVC2) have been fluorimetrically found and two kind of aggregates have been identified and investigated: vesicles above the CVC1 and closely packed aggregates above the CVC2. The sultaine vesicles formed above the CVC1 decreases their stability from 25 to 75°C due to the membrane association promoted at high temperature. Dynamic Laser Light Scattering and fluorescence measurements confirm the presence of larger aggregates above the CVC2 due to the vesicles assembly promoted at high sultaine concentration.Pubblicazioni consigliate
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