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structure of (phospho)lipids significantly influences liposome structure, charge, drug loading capability, and cellular uptake. [2] Consequently, these parameters can often not be controlled independently. Furthermore, special designed lipoids have to be integrated in liposomes during the production process to achieve further functionalization, e.g., targeting structures or "stealth" modification with poly(ethylene glycol) (PEG). [3] PEG-coating was one of the first polymer grafting strategies applied for liposomes. [4] Comparable modifications were performed with lipoid-polymer conjugates bearing polymer species other than PEG, such as polyacrylamides, poly(vinylpyrolidone), and polyglycerol, [5] or modifications with block copolymers. [6] Nevertheless, increased liposome leakage and the loss of vesicular shape have been reported. [7] Furthermore, the common strategy of liposome modification with lipoid-polymer conjugates follows a "preinsertion" strategy that incorporates lipoidpolymer conjugates added to the lipid composition during the liposome formation process, typically via thin lipid film hydration or ethanol injection procedure. [8] An efficient strategy in which the drug is first efficiently encapsulated in a stable vesicle of controlled morphology and, in a second step, the liposome's Liposomes are promising drug carriers already used in clinical practice, but feasible methods for surface modifications are needed to enhance the application spectrum. This work describes the establishment of the first representative of amphiphilic functionalized oligomers as universal tool for the tuning of liposome characteristics based on a flexible building block strategy. The oligomer binds to liposomes composed of different lipids and modifies the surface characteristics. The charge of neutrally and even negatively charged liposomes is switched to a positive surface charge by grafting liposomes with the novel oligomer to create hybrid vesicles while integrity and structure of liposomes is not affected. The role of the alkyl chain anchors of the oligomer as driving force for formation of hybrid vesicles is demonstrated. The oligomer modification of liposomes is utilized to enhance the biological behavior of the vesicles demonstrated by an enhanced uptake in fibroblasts.

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Thermodynamic and structural properties of the N -alkanoyl-substituted α-amino acids threonine and serine, differing only by one CH 3 group in the head group, are determined and compared. Detailed characterization of the influence of stereochemistry proves that all enantiomers form an oblique monolayer lattice structure whereas the corresponding racemates build orthorhombic lattice structures due to dominating heterochiral interactions, except N -C16- dl -serine-ME as first example of dominating homochiral interactions in a racemic mixture of N -alkanoyl-substituted α-amino acids. In all cases, the liquid expanded–liquid condensed (LE/LC) transition pressure of the racemic mixtures is above that of the corresponding enantiomers. Phase diagrams are proposed. Using the program Hardpack to predict tilt angles and cross-sectional area of the alkyl chains shows reasonable agreement with the experimental grazing incidence X-ray diffraction (GIXD) data.

The stratum corneum represents the first skin barrier against chemical and physical damage. These unique properties are based on its peculiar lipid composition with ceramides (CERs) as the main protagonists. In this study, the structural and chemical properties of the α-OH phytosphingosine [AP] CER class have been investigated. α-OH CERs are present in the stratum corneum in their d-forms; however, in most model systems the diastereomer mixture with the synthetically produced l-form is used. The d-form is well-known to form a hydrogen bonding network that helps to reduce the permeability of the lipid matrix, while the l-form does not show any hydrogen bonding network formation. In this paper, 2D (monolayers) and 3D (aqueous dispersions) models have been used to thoroughly study the physical–chemical behaviors of CER­[AP] diastereomers taking into account how the symmetry of the chain pattern influences the behavior of the molecules. The chains of both diastereomers arrange in an oblique unit cell, but only the d-CER­[AP] forms a supramolecular lattice (subgel phase) in both model systems. Interestingly, the chain pattern does not play any role in structure formation since the hydrogen bonding network dictates the packing properties. The 1:1 mixture of the diastereomers phase separates into two domains: one is composed of practically pure d-form and the other one is composed of a mixture of the l-form with a certain amount of d-form molecules.