The Synergy between Topography and Lipid Domains in the Plasma Membrane of Mast Cells Controls the Localization of Signaling Proteins and Facilitates their Coordinated Activation.

Similar to T cells and B cells, mast cell surfaces are dominated by microvilli, and like these other immune cells we showed with microvillar cartography (MC) that key signaling proteins for RBL mast cells localize to these topographical features. Although stabilization of ordered lipid nanodomains around antigen-crosslinked IgE-FcεRI is known to facilitate necessary coupling with Lyn tyrosine kinase to initiate transmembrane signaling in these mast cells, the relationship of ordered-lipid nanodomains to membrane topography had not been determined. With nanoscale resolution provided by MC, SEM and co-localization probability (CP) analysis, we found that FcεRI and Lyn kinase are positioned exclusively on the microvilli of resting mast cells in separate nano-assemblies, and upon antigen-activation they merge into overlapping populations together with the LAT scaffold protein, accompanied by elongation and merger of microvilli into ridge-like ruffles.

A Simple Preparation Method for Full-Range Electron Tomography of Nanoparticles and Fine Powders.

Electron tomography has become a valuable and widely used tool for studying the three-dimensional nanostructure of materials and biological specimens. However, the incomplete tilt range provided by conventional sample holders limits the fidelity and quantitative interpretability of tomographic images by leaving a "missing wedge" of unknown information in Fourier space. Imaging over a complete range of angles eliminates missing wedge artifacts and dramatically improves tomogram quality.

Block copolymer self-assembly-directed single-crystal homo- and heteroepitaxial nanostructures.

Epitaxy is a widely used method to grow high-quality crystals. One of the key challenges in the field of inorganic solids is the development of epitaxial single-crystal nanostructures. We describe their formation from block copolymer self-assembly-directed nanoporous templates on single-crystal Si backfilled with Si or NiSi through a laser-induced transient melt process.

Single-molecule observation of protein adsorption onto an inorganic surface.

Understanding the interactions between silicon-based materials and proteins from the bloodstream is of key importance in a myriad of realms, such as the design of nanofluidic devices and functional biomaterials, biosensors, and biomedical molecular diagnosis. By using nanopores fabricated in 20 nm-thin silicon nitride membranes and highly sensitive electrical recordings, we show single-molecule observation of nonspecific protein adsorption onto an inorganic surface. A transmembrane potential was applied across a single nanopore-containing membrane immersed into an electrolyte-filled chamber.

Atomic-scale imaging of nanoengineered oxygen vacancy profiles in SrTiO3.

At the heart of modern oxide chemistry lies the recognition that beneficial (as well as deleterious) materials properties can be obtained by deliberate deviations of oxygen atom occupancy from the ideal stoichiometry. Conversely, the capability to control and confine oxygen vacancies will be important to realize the full potential of perovskite ferroelectric materials, varistors and field-effect devices. In transition metal oxides, oxygen vacancies are generally electron donors, and in strontium titanate (SrTiO3) thin films, oxygen vacancies (unlike impurity dopants) are particularly important because they tend to retain high carrier mobilities, even at high carrier densities.

Star-shaped azo-based dipolar chromophores: design, synthesis, matrix compatibility, and electro-optic activity.

Three new azo-benzene-based push-pull chromophores with dendritic architecture were synthesized as active materials for electro-optic applications. These chromophores were synthesized in six or seven synthetic steps with an overall yield of around 80% per step and high purity. UV-vis spectroscopy showed significant influence of the transient dipole moment on the observed r(33) values.

Direct fabrication of large micropatterned single crystals.

Micropatterning of single crystals for technological applications is a complex, multistep process. Nature provides alternative fabrication strategies, when crystals with exquisite micro-ornamentation directly develop within preorganized frameworks. We report a bio-inspired approach to growing large micropatterned single crystals.