A series of "viologen" derivatives (4,4'-bipyridinium salts) carrying between 1 and 90 charges per molecule have been prepared and investigated for their activity against human immunodeficiency virus (HIV), herpes simplex virus (HSV), vesicular stomatitis, Punta Toro virus, Sindbis virus, Reovirus, and respiratory syncytial viruses. In general, most of the compounds showed good activities against HIV-1 (strain III(B)). In particular, compound 36 exhibited the highest in vitro activity and selectivity index against HIV-1 (strain III(B)) (EC(50) = 0.26 +/- 0.08 microM, SI = 75.7) in MT-4 cells. The results imply that the antiviral activity requires an optimal number and distance of the positive charges.

bon source and carbonization was performed at 900 C for 7 h [3,4]. The mesoporous carbon was then recovered by etching the silica in HF acid.Characterization: Powder XRD analysis was performed using a Philips 1830 powder diffractometer with Cu K radiation (40 kV, 40 mA). Nitrogen sorption isotherms and textural properties of the materials were determined at ±196 C using nitrogen in a conventional volumetric technique by a Coulter SA3100 sorptometer. Before analysis the samples were oven dried at 150 C and evacuated for 12 h at 200 C under vacuum. The surface area was calculated using the BET method based on adsorption data in the partial pressure (P/P 0 ) range 0.05 to 0.2 and total pore volume was determined from the amount of the nitrogen adsorbed at P/P 0 » 0.99. Scanning electron microscopy (SEM) images were recorded using a JEOL JSM-820 scanning electron microscope. Samples were mounted using a conductive carbon double-sided sticky tape. A thin (ca. 10 nm) coating of gold sputter was deposited onto the samples to reduce the effects of charging. Transmission electron microscopy (TEM) images were recorded on a JEOL 2000-FX electron microscope operating at 200 kV. Samples for analysis were prepared by spreading them on a holey carbon film supported on a grid. Elemental analysis (of the nitrogen-doped carbons) was carried out using a CHNS analyzer (Fishons EA 1108). X-ray photoelectron spectroscopy (XPS) was performed using a Kratos AXIS ULTRA spectrometer with a mono-chromated Al Ka X-ray source (1486.6 eV) operated at 10 mA emission current and 15 kV anode potential. The analysis chamber pressure was better than 10 ±9 torr. FAT (fixed analyser transmission) mode was used, with pass energies of 160 eV (or 80 eV) for survey scans and 40 eV for high resolution scans. A magnetic immersion lens system allowed the area of analysis to be defined by apertures, a slot' aperture of 300 lm 700 lm for wide/survey scans and a 110 lm aperture for high resolution scans. The take off angle for the photoelectron analyzer was 90 and the acceptance angle was 30 (in magnetic lens modes). Data analysis was carried out using CASAXPS software with Kratos sensitivity factors to determine atomic % values from the peak areas. Charge correction was applied to the data at the processing stage. The recent development in mobile electronic equipment has boosted the demand for low-cost flat-panel displays. Today, 90 % of the market is dominated by liquid-crystal displays (LCD), but new technologies such as organic light-emitting diode (OLED) and microencapsulated electrophoretic (MEP) displays have emerged recently.[1] Active or passive matrix addressable displays attract most commercial interest. However, for certain applications, other parameters, such as cost, power consumption, or high contrast are prevailing criteria, and switchable pictograms or icons are sufficient. The phenomenon of electrochromism is well known and involves electrically controlled light absorption in thin layers. [2,3] Alphanumeric electrochromic displays (ECDs) w...

The mechanism of charge propagation in "ion channel sensors" (ICSs) consisting of gold electrodes modified with a layer of charged proteins and highly charged redox-active marker ions in solution was investigated by electrochemical techniques, QCM and AFM. The study is based on seven proteins (concanavalin A, cytochrome c, glucose oxidase, lysozyme, thyroglobulin, catalase, aldolase, and EF1-ATPase) in combination with seven electroactive marker ions ([Fe(CN)6]3-, [Fe(CN)6]4-, [Ru(NH3)6]3+, mono-, di-, and trimeric viologens), as well as a series of suppressor and enhancer ions leading to the following general statements: (i) electrostatic binding of charged marker ions to the domains of the protein is a prerequisite for an electrochemical current and (ii) charge propagation through the layer consists of electron hopping along surface-confined marker ions into the pores between adsorbed proteins. It is further shown that (iii) marker ions and suppressor ions with identical charge compete for oppositely charged sites on the protein domain, (iv) electrostatically bound multilayers of marker or enhancer ions with alternating charge form on a charged protein domain, and (v) self-exchange and exergonic ET catalysis between adsorbed marker ions and marker ions in solution take place. In addition to fundamental insight into the mechanism of charge propagation, valuable information for the design, optimization, and tailoring of new biosensors based on the ICS concept is demonstrated by the current findings.

A series of "viologen" based dendrimers with polycationic scaffold carrying 10, 18, 26, 42, and 90 charges per molecule were used to determine the structure-activity relationship (SAR) with regard to HIV-1 inhibitory activity. The studies involved five compounds with a high activity against HIV-1 already utilized in our previous study (1) and five new dendrimers. Such dendrimers block HIV-1 entry into the cell, indicating that they bind to HIV-1 surface proteins and/or on the host cell receptors required for entry. The increasing positive character of dendrimers leads to more cytotoxicity. The 10 charges dendrimers (1, 6) have less influence on the cell viability but low inhibition of the binding of the CXCR4 mAb clone 1D9. Thus, dendrimers with 18 charges (2, 7) are the most promising CXCR4 imaging probes. We report the design, synthesis, and biological activity of new HIV-1 inhibitors that are conceptually distinct from those of the existing HIV-1 inhibitors.

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