In the discipline of bottom-up synthetic biology, vesicles define the boundaries of artificial cells and are increasingly being used as biochemical microreactors operating in physiological environments. As the field matures, there is a need to compartmentalize processes in different spatial localities within vesicles, and for these processes to interact with one another. Here we address this by designing and constructing multi-compartment vesicles within which an engineered multi-step enzymatic pathway is carried out. The individual steps are isolated in distinct compartments, and their products traverse into adjacent compartments with the aid of transmembrane protein pores, initiating subsequent steps. Thus, an engineered signalling cascade is recreated in an artificial cellular system. Importantly, by allowing different steps of a chemical pathway to be separated in space, this platform bridges the gap between table-top chemistry and chemistry that is performed within vesicles.

Effect of fluoride content of bioactive glasses on apatite deposition in simulated body fluid 2/15Summary Bioactive glasses are able to bond to bone through formation of carbonated hydroxyapatite in body fluids, and fluoridereleasing bioactive glasses are of interest for both orthopaedic and in particular dental applications for caries inhibition.Melt-derived glasses in the system SiO 2 -P 2 O 5 -CaO-Na 2 O with increasing amounts of CaF 2 were prepared by keeping network connectivity and the ratio of all other components constant.pH change, ion release and apatite formation during immersion of glass powder in simulated body fluid at 37°C over up to two weeks were investigated. Crystal phases formed in SBF were characterised using infra-red spectroscopy, X-ray diffraction with Rietveld analysis and solid-state nuclear magnetic resonance spectroscopy ( 19 F and 31 P MAS-NMR).Results show that incorporation of fluoride resulted in a reduced pH rise in aqueous solutions compared to fluoride-free glasses and in formation of fluorapatite (FAp), which is more chemically stable than hydroxyapatite or carbonated hydroxyapatite and therefore is of interest for dental applications. However, for increasing fluoride content in the glass, fluorite (CaF 2 ) was formed at the expense of FAp. Apatite formation could be favoured by increasing the phosphate content in the glass, as the release of additional phosphate into the SBF would affect supersaturation in the solution and

No abstract

SummaryFluoride prevents dental cavities, stimulates bone mineralisation and decreases the melting temperature of glasses and is therefore an interesting component of bioactive glasses for use as dental or orthopaedic biomaterials. However, when designing new glass compositions, the structural role of fluoride in the glass needs to be better understood. We have characterised a glass series in the system SiO 2 -P 2 O 5 -CaO-Na 2 O with increasing concentrations of CaF 2 . Network connectivity was fixed at 2.13 by adding CaF 2 while the ratio of all other components was kept constant. 19

The field of drug-membrane interactions is one that spans a wide range of scientific disciplines, from synthetic chemistry, through biophysics to pharmacology. Cell membranes are complex dynamic systems whose structures can be affected by drug molecules and in turn can affect the pharmacological properties of the drugs being administered. In this tutorial review we aim to provide a guide for those new to the area of drug-membrane interactions and present an introduction to areas of this topic which need to be considered. We address the lipid composition and structure of the cell membrane and comment on the physical forces present in the membrane which may impact on drug interactions. We outline methods by which drugs may cross or bind to this membrane, including the well understood passive and active transport pathways. We present a range of techniques which may be used to study the interactions of drugs with membranes both in vitro and in vivo and discuss the advantages and disadvantages of these techniques and highlight new methods being developed to further this field.