Impact of Colloids as Defects on the Structure Formation of Membrane-Forming Amphiphiles and Amphiphilic Block Copolymers
Project area:
Physical Chemistry of Molecules, Liquids, and Interfaces, Biophysical Chemistry
Project leaders:
Maskos, Michael, Prof. Dr.
Johannes Gutenberg University Mainz
Department of Chemistry
Duesbergweg 10-14, 55128 Mainz
+49 (0)6131 39-36119
maskos[a]uni-mainz.de
Bleul, Regina, Dr.
Fraunhofer Institute for Microengineering and Microsystems IMM
Carl-Zeiss-Str. 18-20, 55129 Mainz
+49 (0)6131 990-168
regina.bleul[a]imm.fraunhofer.de
Summary
For decades, membrane-forming amphiphiles have proven its importance as building components of versatile carrier and model systems. Even though liposomal carrier systems have been investigated in clinical applications since the 1990s, central questions regarding release mechanisms or the controlling of membrane permeability remain open until today. The permeability of bio membranes is set by additional molecules such as membrane proteins and ionic channels that create “defects” in the membrane. The effects of such defects are not adequately investigated neither for natural lipid membranes of biological origin nor for artificial membranes composed of polymers and surfactants.
However, complex mechanisms and phenomena such as local microphase separation and de-mixing,
clustering and domain formation are of great importance in controlling the self-assembly process of
membranes. Therefore, this project aims to control the self-assembly process of amphiphiles in the presence of colloidal nanostructures in order to improve the understanding on defect generation and its effects on the integrity and permeability of engineered vesicular membranes. This aim will be accomplished by investigating and exploiting the self-assembly process for small amphiphiles of natural or synthetic origin or polymeric amphiphiles in presence of inorganic colloid systems. In this project we choose low molecular weight phospholipids and non-ionic surfactants as small amphiphiles, di- and triblock-copolymers of varying molecular weight and different colloid systems. Hereby, the focus will be laid on noble metal and silica nanoparticles (mainly as model systems), magnetic iron oxide nanoparticles (spherical as well as disk-like as representatives for advanced imaging tracers as well as for magnetic fluid hyperthermia agents), fluorescent nanoparticles, i.e. quantum dots, and nanodiamonds (as nanosensoric systems).
Our expertise and experience particularly in micromixing technology to perform continuous formulation
processes of nanostructures will be applied to study the mechanisms and the dynamics of membrane formation of amphiphiles in presence of colloids as defect generating sources. Continuous micromixing technology allows a tight control over the reaction parameters and, in turn, results in high reproducibility and repeatability of the nanomaterial properties. Moreover, the powerful micromixing technique enables to study self-assembled structures not only at the thermodynamic equilibrium, but also to gain knowledge on the kinetics and mechanisms during self-assembly in presence of inorganic colloids. Resulting membrane structures, modified with induced defects caused by the colloid integration will be investigated comprehensively and analyzed with specific nanoanalytical tools at Fraunhofer IMM (e.g. flow dynamic light scattering, cryogenic transmission electron microscopy) and augmented by further techniques in collaboration within this SFB (X-ray photon correlation spectroscopy, magnetic nanoscopy, etc.).