betadex and phosphorylethanolamine

We report a means by which atomic and molecular secondary ions, including cholesterol and fatty acids, can be sputtered through single-layer graphene to enable secondary ion mass spectrometry (SIMS) imaging of untreated wet cell membranes in solution at subcellular spatial resolution. We can observe the intrinsic molecular distribution of lipids, such as cholesterol, phosphoethanolamine and various fatty acids, in untreated wet cell membranes without any labeling. We show that graphene-covered cells prepared on a wet substrate with a cell culture medium reservoir are alive and that their cellular membranes do not disintegrate during SIMS imaging in an ultra-high-vacuum environment. Ab initio molecular dynamics calculations and ion dose-dependence studies suggest that sputtering through single-layer graphene occurs through a transient hole generated in the graphene layer. Cholesterol imaging shows that methyl-β-cyclodextrin preferentially extracts cholesterol molecules from the cholesterol-enriched regions in cell membranes.

Topics: beta-Cyclodextrins; Cell Membrane; Cholesterol; Diagnostic Imaging; Ethanolamines; Fatty Acids; Graphite; Molecular Dynamics Simulation; Single-Cell Analysis; Spectrometry, Mass, Secondary Ion

A novel biodegradable amphiphilic copolymer composed of hydroxypropyl-β-cyclodextrin, polylactide, and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine, was successfully synthesized. The chemical structures of copolymers were determined by FT-IR, (1)H nuclear magnetic resonance (NMR) spectroscopy, (13)C NMR, (31)P NMR, thermogravimetric analysis ,and differential scanning calorimetry. Doxorubicin (DOX)-loaded copolymer nanoparticles (NPs) were prepared by double emulsion and nanoprecipitation methods. The factors of copolymer composition and fabrication methods, which influence size and encapsulation efficiency (EE) were investigated. Their EE to DOX could reach 90.6% at an available condition. In vitro release behavior of NPs showed a continuous release after a burst release. The antitumor activity of the DOX-loaded NPs against cancer HepG2 and A549 cells was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. The DOX-loaded copolymer NPs showed comparable anticancer efficacy with the free drug.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Antibiotics, Antineoplastic; beta-Cyclodextrins; Carcinoma, Non-Small-Cell Lung; Cell Survival; Doxorubicin; Drug Carriers; Ethanolamines; Excipients; Hep G2 Cells; Humans; Hydrophobic and Hydrophilic Interactions; Nanoparticles; Polyesters; Polymers; Tumor Cells, Cultured

The continuous nature of micro free-flow electrophoresis (mu-FFE) was used to monitor the effect of a gradient of buffer conditions on the separation. This unique application has great potential for fast optimization of separation conditions and estimation of equilibrium constants. COMSOL was used to model pressure profiles in the development of a new mu-FFE design that allowed even application of a buffer gradient across the separation channel. The new design was fabricated in an all glass device using our previously published multiple-depth etch method (Fonslow, B. R.; Barocas, V. H.; Bowser, M. T. Anal. Chem. 2006, 78, 5369-5374, ref 1). Fluorescein solutions were used to characterize the applied gradients in the separation channel. Linear gradients were observed when buffer conditions were varied over a period of 5-10 min. The effect of a gradient of 0-50 mM hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on the separation of a group of 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) labeled primary amines was monitored as a proof of concept experiment. Direct comparisons to capillary electrophoresis (CE) separations performed under the same conditions were made. Gradient mu-FFE recorded 60 separations during a 5 min gradient allowing nearly complete coverage across a range of HP-beta-CD concentrations. In comparison, 4 h were required to assess 15 sets of conditions across the same range of HP-beta-CD concentrations using CE. Qualitatively, mu-FFE separations were predictive of the migration order and spacing of peaks in CE electropherograms measured under the same conditions. Data were fit to equations describing 1:1 analyte-additive binding to allow a more quantitative comparison between gradient mu-FFE and CE.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; 4-Chloro-7-nitrobenzofurazan; Amino Acids; beta-Cyclodextrins; Buffers; Electrophoresis; Ethanolamines; Fluorescein; Fluorescent Dyes; Kinetics; Models, Theoretical; Viscosity