Bilayer lipid membrane formation on surface assemblies with sparsely distributed tethers.

A combined computational and experimental study of small unilamellar vesicle (SUV) fusion on mixed self-assembled monolayers (SAMs) terminated with different deuterated tether moieties (-(CD)CD or -(CD)CD) is reported. Tethered bilayer lipid membrane (tBLM) formation of synthetic 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine was initially probed on SAMs with controlled tether (d-alkyl tail) surface densities and lateral molecular packing using quartz crystal microbalance with dissipation monitoring (QCM-D). Long time-scale coarse-grained molecular dynamics (MD) simulations were then employed to elucidate the mechanisms behind the interaction between the SUVs and the different phases formed by the -(CD)CD and -(CD)CD tethers.

Mixed Self-Assembled Monolayers with Terminal Deuterated Anchors: Characterization and Probing of Model Lipid Membrane Formation.

We describe herein a series of self-assembled monolayers (SAMs) on gold designed for adjustable tethering of model lipid membrane phases. The SAMs consist of deuterated aliphatic anchors, HS(CH)CONH(CHCHO)CHCONH-X, where X is either -(CD)CD or -(CD)CD, dispersed in a stable matrix of protein-repellent molecules, HS(CH)CONHCHCHOH. The mixed SAMs with variable surface densities of the anchors are thoroughly characterized before and after adsorption of phospholipids by means of ellipsometry, contact angle goniometry, and infrared reflection-absorption spectroscopy (IRRAS).

Protein-resistant hyperbranched polyethyleneimine brush surfaces.

A novel hyperbranched polyethyleneimine (PEI) modified gold surface has been designed, fabricated, and investigated with respect to its ability to resist non-specific adsorption of proteins. The facile synthesis strategy, based on self-assembly, involves immobilization of polyethyleneimine to gold surfaces modified with 11-mercaptoundecanoic acid (MuDA) monolayers using traditional carbodiimide chemistry. The hyperbranched polymer brushes were characterized by X-ray photoelectron spectroscopy (XPS).

Saccharide-functionalized alkanethiols for fouling-resistant self-assembled monolayers: synthesis, monolayer properties, and antifouling behavior.

We describe the synthesis of a series of mono-, di-, and trisaccharide-functionalized alkanethiols as well as the formation of fouling-resistant self-assembled monolayers (SAMs) from these. The SAMs were characterized using ellipsometry, wetting measurements, and infrared reflection-absorption spectroscopy (IRAS). We show that the structure of the carbohydrate moiety affects the packing density and that this also alters the alkane chain organization.

Fluorescence and FTIR Spectra Analysis of Trans-A₂B₂-Substituted Di- and Tetra-Phenyl Porphyrins.

A series of asymmetrically substituted free-base di- and tetra-phenylporphyrins and the associated Zn-phenylporphyrins were synthesized and studied by X-ray diffraction, NMR, infrared, electronic absorption spectra, as well as fluorescence emission spectroscopy, along with theoretical simulations of the electronic and vibration structures. The synthesis selectively afforded trans-A₂B₂ porphyrins, without scrambling observed, where the AA and BB were taken as donor- and acceptor-substituted phenyl groups. The combined results point to similar properties to symmetrically substituted porphyrins reported in the literature.

Long-chain alkylthiol assemblies containing buried in-plane stabilizing architectures.

A series of alkylthiol compounds were synthesized to study the formation and structure of complex self-assembled monolayers (SAMs) consisting of interchanging structural modules stabilized by intermolecular hydrogen bonds. The chemical structure of the synthesized compounds, HS(CH(2))(15)CONH(CH(2)CH(2)O)(6)CH(2)CONH-X, where X refers to the extended chains of either -(CH(2))(n)CH(3) or -(CD(2))(n)CD(3), with n = 0, 1, 7, 8, 15, was confirmed by NMR and elemental analysis. The formation of highly ordered, methyl-terminated SAMs on gold from diluted ethanolic solutions of these compounds was revealed using contact angle goniometry, null ellipsometry, cyclic voltammetry, and infrared reflection absorption spectroscopy.