Biomimetic structural composites

In this context it is interesting to note that archaea, which possess S-layers as exclusive cell wall components outside the cytoplasmic membrane (Fig. 14), exist under extreme environmental conditions (e.g., high temperatures, hydrostatic pressure, and salt concentrations, low pH values). Thus, it is obvious one should study the effect of proteinaceous S-layer lattices on the fluidity, integrity, structure, and stability of lipid membranes. This section focuses on the generation and characterization of composite structures that mimic the supramolecular assembly of archaeal cell envelope structures composed of a cytoplasmic membrane and a closely associated S-layer. In this biomimetic structure, either a tetraether... 

FIG. 14 Schematic illustration of an archaeal cell envelope structure (a) composed of the cytoplasmic membrane with associated and integral membrane proteins and an S-layer lattice, integrated into the cytoplasmic membrane, (b) Using this supramolecular construction principle, biomimetic membranes can be generated. The cytoplasmic membrane is replaced by a phospholipid or tetraether hpid monolayer, and bacterial S-layer proteins are crystallized to form a coherent lattice on the lipid film. Subsequently, integral model membrane proteins can be reconstituted in the composite S-layer-supported lipid membrane. (Modified from Ref. 124.)... 

The only clinically approved and therefore most studied natural siderophore is des-ferrioxamine B (DFO), and hence it serves as a reference compound in evaluating new biomimetic siderophores. The following discussion will include a short description of several natural hydroxamate siderophore families in separate tables, followed by the various attempts to prepare novel simplified structures that reproduce biological activity. These tables are not intended to cover the entire archive of known siderophores, but merely to allow the reader to observe structural variations, their chemical composition and location as well as conserved domains. 

From Composite to Complex Structures. .. Through Biomimetics... 

Self-assembled and spontaneously adsorbed monolayers offer a facile means of controlling the chemical composition and physical structure of a surface. As discussed later in Chapter 5, applications of these monolayers include modeling election transfer reactions, biomimetic membranes, nano-scale photonic devices, solar energy conversion, catalysis, chemical sensing and nano-scale lithography. 

Following the introduction of MCM-41 type materials [1], the synthesis of surfactant templated nanostructured materials has attracted the attention of the scientific community because it provides the possibility of tailoring pore size, geometry and surface chemistry through control of the synthesis conditions. Potential applications of these materials range from separations and catalysis [2] to the production of biomimetic materials [3] and devices for optical and electronic applications [4]. Several synthesis protocols have been developed in the last ten years and are the focus of many recent reviews [5]. Despite the enormous experimental effort to develop methods to control the structure and composition of templated nanoporous materials, modeling the different processes has remained elusive, mainly due to the overlapping kinetic and thermodynamic effects. The characterization of... 

---