Catanoinic systems spontaneously form micelles and vesicles, which are self-assembled spherical structures made up by surfactants. In the core of the micelle a drug, or other organic substance, can be kept to stabilize it when placed in an aqueous environment. The micelle-to-vesicle transition corresponds to the moment when the drug is releases, and understanding which factors that trigger this transition is thus of great interest for the pharmaceutical industry. In this study the micelle-to-vesicle transition in water and the effect of salt were studied for the systems 95 mol% SDS/DDAB and 95 mol% SDeS/DDAB with different total concentrations. The static light scattering measurements showed that the micelle-to-vesicle transition for the system 95 mol% SDS/DDAB was shifted to lower total concentrations both when 50 mM NaBr and 100 mM NaBr were added, and that the transition was unaffected by changing the anionic surfactant from SDS to SDeS when no salt had been added. A phase separation was observed when 50 mM NaBr was added to 95 mol% SDeS/DDAB (the Krafft point was probably reached), and when 100 mM NaBr was added to the same system the sample remained opaque one week after mixing the sample and also after heating it to 40°C in a water bath. The curve for sample 95 mol% SDS/DDAB 1/8192 mM + 100 mM NaBr was oscillating implying possible defects in the vesicle membrane. The cryo-TEM images confirmed the light scattering results and additionally showed that at higher total concentrations agglomeration occurred, while whenever salt was added less vesicles seemed to appear, while both discs and broken vesicles were present suggesting that the disc structure is preferred over the spherical structure when salt is present. Also a vesicle inside another vesicle was discovered for the sample 0.95 SDS/DDAB 3.75 mM + 50 mM NaBr. The mole fraction of anionic surfactant in the aggregates (x) was calculated using a MATLAB code based on the Poisson-Boltzmann theory. The results from the calculations showed that a higher amount of SOS was needed for the system 0.95 SOS/CTAB than the amount of SDS and SDeS needed for the systems 0.95 SDS/DDAB and 0.95 SDeS/DDAB when forming aggregates, indicating that a shorter chain of the anion and the higher spontaneous curvature of the cation leads to a higher curvature. Also a larger amount of cation was needed when the tail was single than when it was double in order to form stable spherical structures. Finally, as the total concentration decreased the x value also decreased in all cases, thus the spontaneous curvature was decreased.

Aujourd'hui, un grand nombre de nouvelles molécules peuvent être synthétisées à partir de la biomasse. Les tensioactifs dérivés de sucre sont notamment considérés comme une alternative aux tensioactifs fossiles en raison de leur biodégradabilité et de leur biocompatibilité. Cependant, les études associant la caractérisation physico-chimique et les propriétés biologiques de ce type de tensio-actifs sont limitées. Il est ainsi difficile de prédire les propriétés d'un tensioactif à partir de sa structure chimique. L'établissement d'une méthodologie permettant de relier la structure des surfactants à leurs propriétés apparait pertinent. Dans ce travail, quatre surfactants dérivés de sucre ayant chacun une chaîne C8 liée à une tête glucose ou maltose par un groupe amide ont été caractérisés par leurs propriétés tensio-actives dans différentes solutions (eau et milieu biologique). Leurs interactions avec des protéines ont également été analysées. Concernant l'évaluation des propriétés biologiques, des tests de cytotoxicité/irritation ont été effectués sur trois modèles in-vitro : 1) modèle cellulaire 20 (cellules L929 cultivées en monocouche), Il) modèle cellulaire 30 (cellules L929 cultivées dans un gel de collagène), Ill) épiderme humain reconstitué. Les résultats indiquent que les quatre surfactants synthétisés présentent de bonnes propriétés tensio-actives et trois d'entre eux sont moins cytotoxiques que des tensioactifs de référence. Plusieurs hypothèses permettant de relier la structure chimique des molécules à leurs propriétés physico-chimiques et biologiques ont été proposées. Des travaux futurs permettront d'enrichir la base de données sur les relations structure-propriétés des tensioactifs issus de la biomasse, et de l'utiliser pour synthétiser des surfactants présentant des propriétés adaptées aux applications envisagées. / Nowadays, a wide variety of new molecules can derive from biomass. Among them, the family of sugar-based surfactants, which are considered as alternatives to fossil-based surfactants, due to their relatively high biodegradability and biocompatibility, exhibit interesting properties both in terms of their self-assembly and their ability to induce biological responses. In the study, for the purpose to analyse these properties, different methodologies have been established. In this work, physico-chemistry and cellular biology methodologies are associated to analyse the properties of pre-selected molecules characterized by gradua) structure modifications. Firstly, we have screened synthesized sugar-based surfactants according to their solubility and their ability to reduce surface tension of water. Four pre-selected molecules, with a C8 chain linked to a glucose or maltose head through an amide functional group, either under the form of carbamoyl (carbohydrate scaffold bearing the carbonyl) or alkylcarboxamide (the alkyl chain bearing the carbonyl), were then dissolved in water/ cell culture media for surface tension measurements. Their behaviors in solutions were characterized by Krafft points, Critical Micellar Concentrations or self-assembling properties through different methods. To evaluate the cytotoxic/ irritant effects of these molecules on cells and tissues, 3 in-vitro models were established: I) 2D cell culture mode! (L929 cell monolayer) II) 3D ce!! culture mode! (L929 cells embedded in collagen gel) and III) Reconstituted human epidermis (differentiated human keratinocytes). Corresponding experiments were carried out on these models with increasing complexity. Results show that the synthesized sugar-based surfactants, GlulamideC8, Glu6amideC8, Glu6amideC8' and MallamideC8 can reduce the surface tension of water solution to the came level as standard surfactants (Tween 20 and Hecameg). In the meantime, GlulamideC8, Glu6amideC8' and MallamideC8 present Iess cytotoxicity effects on L929 cells both in the monolayer model and the 3D mode! than Tween 20 and Hecameg. All synthesized and standard surfactants (GlulamideC8, Glu6amideC8, Gu6amideC8', MallamideC8, Tween 20 and Hecameg) have no significant cytotoxic/ irritant effects on reconstituted human epidermis at 1000 ig/mL after 48 h of topical application. Discussions have been made according to the results of experiments to establish possible structures/ physico-chemical properties - cytotoxicity relationships of these surfactants.