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This article presents the recent progress of synchrotron scattering methods for elucidating the self-assembly pathways in dilute surfactant systems. An order of magnitude increases in the source brilliance, together with advanced detectors enable time-resolved structural investigations of relatively low contrast and dilute surfactant solutions in the millisecond range. This is demonstrated by monitoring the structural evolution in mixtures of cationic and anionic surfactants well below their individual critical micelle concentration, upon rapid mixing using a stopped-flow device. Despite the low concentration of surfactants in these samples, well-defined nanostructures were detected within in the mixing time of the stopped-flow device (ca. 2 ms). These transient structures have a more elongated morphology than spherical unilamellar vesicles and they grow over the subsequent seconds. The results demonstrate that the spontaneous self-assembly occurs even in dilute solutions without any pre-existing motifs, which may be relevant in applications where high surfactant concentrations are inappropriate. [ABSTRACT FROM AUTHOR]

Viruses have been of interest to mankind since their discovery as small infectious agents in the nineteenth century. Because many viruses cause diseases to humans and agriculture, they were rigorously studied for biological and medical purposes. Viruses have remarkable properties such as the symmetry and self-assembly of their protein envelope, maturation into infectious virions, structural stability, and disassembly. Solution X-ray scattering can probe structures and reactions in solutions, down to subnanometer spatial resolution and millisecond temporal resolution. It probes the bulk solution and reveals the average shape and average mass of particles in solution and can be used to study kinetics and thermodynamics of viruses at different stages of their life cycle. Here we review recent work that demonstrates the capabilities of solution X-ray scattering to study in vitro the viral life cycle. [ABSTRACT FROM AUTHOR]

Soft nanoarchitectures created by biomimetic self-assembly offer unexploited potential for therapeutic drug delivery applications, tissue engineering, and diagnostics. The lipid bilayer building blocks impart biocompatible properties and low toxicity of the resulting nanoassemblies. Our work provides a survey of the recent advances in design and structural studies of functional bicontinuous soft porous nanoarchitectures created from amphiphilic bilayer membrane building blocks. Depending on the packing symmetries and the densities of the curved lipid bilayers, organized in membrane-type nanoparticles, a class of multicompartment nanoobjects involving cubosomes, spongosomes, onion-like liposomes, or vesicles arranged in hierarchical supramolecular architectures, can be obtained. High resolution structural investigations by cryo-transmission electron microscopy microscopy and time-resolved small-angle X-ray scattering (SAXS) have demonstrated that binding and complexation of rigid protein molecules to flexible membrane-vesicle building blocks may generate significant changes in the curvature of the membrane interfaces and may induce formation of bicontinuous cubic nanoarchitectures. Enzyme-mediated cubic nanoarchitecture generation represents another low-energy fabrication method of nanoporous liquid crystalline assemblies. The kinetic pathway of packing ready-to-assemble membrane building blocks (vesicles, nanocubosomes) into nanoarchitectonic vehicles has been revealed by rapid-mixing stopped-flow SAXS experiments. [ABSTRACT FROM AUTHOR]

This review covers recent studies on the characterization of the dynamics of lipidic nanostructures formed via self-assembly processes. The focus is placed on two main topics: First, an overview of advanced experimental small-angle X-ray scattering (SAXS) setups combined with various sample manipulation techniques including, for instance, stop-flow mixing or rapid temperature-jump perturbation is given. Second, our recent synchrotron SAXS findings on the dynamic structural response of gold nanoparticle-loaded vesicles upon exposure to an ultraviolet light source, the impact of rapidly mixing negatively charged vesicles with calcium ions, and in situ hydration-induced formation of inverted-type liquid-crystalline phases loaded with the local anesthetic bupivacaine are summarized. These in situ time-resolved experiments allow real-time monitoring of the dynamics of the structural changes and the possible formation of intermediate states in the millisecond to second range. The need for investigating self-assembled systems, mainly stimuli-responsive drug nanocarriers, under nonequilibrium conditions is discussed. For pharmaceutically relevant applications, it is essential to combine these investigations with appropriate in vitro and in vivo studies. [ABSTRACT FROM AUTHOR]