2-(4-Fluoro­phen­yl)-1-(4-meth­oxy­phen­yl)-4,5-dimethyl-1H-imidazole

In the title compound, C18H17FN2O, the imidazole ring makes dihedral angles of 76.46 (7) and 40.68 (7)° with the meth­oxy­phenyl and fluoro­phenyl rings, respectively. The dihedral angle between the two benzene rings is 71.25 (6)°

Lophine (2,4,5-triphenyl-1H-imidazole)

The title compound, C21H16N2, has been known since 1877. Although the crystal structure of 36 derivatives of lophine are known, the structure of parent compound has remained unknown until now. The three phenyl rings bonded to the imidazole core are not coplanar with the latter, with dihedral angles of 21.4 (3), 24.7 (3), and 39.0 (3)°, respectively, between the phenyl ring planes in the 2-, 4- and 5-positions of the imidazole ring. The mol­ecules are packed in layers running perpendicular to the b axis. Although there are acceptor and donor atoms for hydrogen bonds, no such inter­actions are detected in the crystal in contrast to other lophine derivatives

Effect of Cationic Surfactants on Enhancement of Firefly Bioluminescence in the Presence of Liposomes

Firefly bioluminescence (BL) was greatly affected by cationic surfactants coexisting with liposomes containing phosphatidylcholine and cholesterol. In this study, the effects of the type and concentration of cationic surfactants on BL were studied in the presence of the liposomes. Three types of cationic surfactant: benzalkonium chloride (BAC), n-dodecyltrimethylammonium bromide (DTAB), and benzethonium chloride (BZC), were used. As a common effect in these surfactants, BL intensity was increased and then drastically decreased with increasing surfactant concentration. This can be explained by the formation of cationic liposomes as BL enhancers at low concentration of the surfactant, and by the transformation into cationic (mixed) micelles as inhibitors at high concentration. The maximal BL intensity and the concentration for the maximal BL were dependent on the type of the surfactants. To explain the differences in these parameters in the enhanced BL, we determined the distribution coefficient, K, of the surfactants to the liposomal membrane. The result indicated that the surfactant with higher K value gives the maximal BL intensity at lower concentration

Application of Horseradish Peroxidase-Encapsulated Liposomes as Labels for Immunodotblotting

Liposomes are spherical vesicles consisting of phospholipid bilayers surrounding an aqueous volume. Recently, attention has focused on liposomes as a signal-enhancement agent, since a number of marker molecules can be encapsulated in their aqueous interior. An antibody labeled with liposome encapsulating enzyme, such as glucose oxidase, has been employed for immunoassays. On the other hand, HRP-conjugated liposomes were prepared by covalently attaching HRP to the outside of the lipid bilayer of liposome. However, the preparation of HRP-conjugated liposomes was tedious and time-consuming, since several reaction steps are required for linking HRP covalently to the surface of liposomes. In order to hold simply HRP in liposomes, we examined how to encapsulate HRP into the aqueous interior of liposomes prepared by an extrusion technique (VETs).4 In addition, the HRP-encapsulated VETs were coupled covalently to anti-rabbit IgG(antibodytagged VETs).5 the detection of HRP encapsulated in the antibody-tagged VETs was made by luminol chemiluminescent (CL) method. On the other hand, biotin-tagged molecules are currently more universal as a marker in immunoassays compared to antibody-tagged marker moleucles. In the present study, the HRP-encapsulated liposomes containing biotinylated dipalmitoylphosphatidylethanolamin were prepared by an extrusion technique (biotin-tagged VETs). In addition, biotin-tagged VETs were applied to labels in immunodotblotting of rabbit IgG

On-chip genotoxic bioassay based on bioluminescence reporter system using three-dimensional microfluidic network

Microchip-based genotoxic bioassay using sensing Escherichia coli strains has been performed. In this method, the assay was conducted in three-dimensional microfluidic network constructed by a silicon perforated microwell array chip and two poly(dimethylsiloxane) (PDMS) multi-microchannel chips. The sensing strains having firefly luciferase reporter gene under transcriptional control of umuD as an SOS promoter were put into the channels on one of the PDMS chips and immobilized in the silicon microwells. Samples containing genotoxic substances and substrates for luciferase were into the channels on the other PDMS chip. The optimum conditions of the assay in the on-chip format have been investigated using mitomycin C (MMC) as a genotoxic substance. As a result, the dose-dependence of bioluminescence intensity was obtained at once on the chip. Additionally, the response ratios of the bioluminescence between mutagen- and non-induced strains were successfully enhanced by improving the on-chip assay methods and conditions. Several well-known genotoxic substances were subjected to the on-chip assay, and were detected with the detection limits comparable to those in the conventional method with reduced time

Aqueous Micellar Two-Phase Systems for Protein Separation

The extractive technique for protein purification based on two-phase separation in aqueous micellar solutions (aqueous micellar two-phase system (AMTPS)) is reviewed. The micellar solution of a nonionic surfactant, such as polyoxyethyl-ene alkyl ether, which is most frequently used for protein extraction, separates into two phases upon heating above its cloud point. The two phases consist of a surfactant-depleted phase (aqueous phase) and a surfactant-rich phase. Hydrophilic proteins are partitioned to the aqueous phase and hydrophobic membrane proteins are extracted into the sur-factant-rich phase. Because of the methodological simplicity and rapidity, this technique has become an effective means, and thus has been widely used for the purification and characterization of proteins. In contrast to polyoxyethylene alkyl ether, micellar solutions of a zwitterionic surfactant, such as alkylammoniopropyl sulfate, separate below the critical temperature. Alkylglucosides can also separate into two phases upon adding water-soluble polymers. Recently, these two-phase systems have been exploited for protein separation. Additionally, hydrophobic affinity ligands, charged polymers, and ionic surfactants have been successfully used for controlling the extractability of proteins in AMTPS

Uptake of Transition Metal Ions Using Liposomes Containing Dicetylphosphate as a Ligand

The uptake of Cu2+ was investigated using various types of liposomes composed of phosphatidylcholine (PC), cholesterol (Chol) and dicethylphosphate (DCP). DCP played a role as a ligand for Cu2+. Multilamellar vesicles (MLVs) were more effective for the uptake of Cu2+ compared to unilamellar vesicles prepared by the extrusion technique. The uptake efficiency of MLVs for Cu2+ was dependent on the molar ratio of DCP in MLVs. The uptake percent of Cu2+ was 92% using MLVs having a PC:DCP:Chol molar ratio of 4:3:3; 95% of the total vesicle Cu2+ was bound to DCP of the outer membrane surface of the MLVs, and the remaining 5% of the total Cu2+ was distributed into the interior side of the MLVs. MLVs having a PC:DCP:Chol molar ratio of 4:3:3 were also effective as separation media for Mn2+, Co2+, Ni2+ and Zn2+. The uptake efficiency of the MLVs for the transition-metal ions increased in the order Co2+< Zn2+ < Ni2+ < Mn2+ < Cu2+