Willner studies

What the Willner study highlights is the enormous possibilities of connecting electronic elements to proteins using nanopartides. In particular, the absence of... 

As dehydrogenases (DH) are widely distributed enzymes, a number of studies have been carried out with these biocatalysts. For example, Willner el al. [20] have used a PQQ-monolayer functionalized gold electrode for the catalytic oxidation of NADH in the presence of Ca2+. In this scheme, the pyrrolo-quinoline quinine co-factor, PQQ, was covalently linked, as before for the GOx system [15, 20, 21], to the Au electrode,... 

In a number of cases ITIES can be used to separate the products of a photoinduced electron-transfer reaction. An early example is the work by Willner et al. [7] at the water/toluene interface, who studied the photooxidation of [Ru(bpy)3]2+ in the aqueous phase. The excited state was quenched by hexadecyl- 4,4 bipyridinium, which becomes hydrophobic on reduction and crosses to the toluene phase. There are other examples and mechanisms at the present time their main interest resides in their chemistry, and in the separation of products that can be achieved at the interface. 

Van Huis and Schaefer [8] found that CIO4 has a minimum electronic energy structure of C2v symmetry in contrast with an experimental assignment from infrared spectra by Grothe and Willner [9]. These authors arrived at C31, as the appropriate symmetry group for CIO4 in a neon matrix. The continued interest in the perchlorate radical has prompted the present small study of its electronic features and bonding characteristics. 

Attempts to establish the existence and structure of chlorine tetraoxide have not led to a unique and undisputed situation. Byberg identified the species in his comprehensive studies on crystalline forms such as irradiated potassium perchlorate and was led to the exchange coupled interpretation [7]. Studies of the species in a neon matrix suggested the C31, form to Grothe and Willner [9]. Somewhat elaborate calculations by Van Huis and Schaefer [8] favor the C21, geometry as an optimized structure of the isolated radical. 

The main idea demonstrated by Willner and coworkers [20] is the ability to construct multilayered nanoparticle electrodes, which are porous. In a related study Patolsky et al. extended this idea further using biocatalysts to detect H2O2 [18]. In this example, the construction of the electrode is similar to the one described above but the redox-active bridging molecule was replaced with microperoxidase-11 (MP-11). 

Willner and Halpern185 have described quantitative O-methylation of ac-ridone (119) under phase transfer conditions. But a more detailed study on alkylation of acridone under biphasic conditions by Galy et al.1 6 arrives at another conclusion the reaction gives a mixture of N- and O-alkylation products, with the N-alkyl derivative (120) predominating (65-100%). The yield of isolated N-alkyl derivative is 41-66%. 

Di Chiara G, Acquas E, Carboni E (1991) In P. Willner and J. Scheel-Kruger (eds) Role of mesolimbic dopamine in the motivational effects of drug brain dialysis and place preference studies. In The mesolimbic dopamine system from motivation to action. John Wiley and Sons Publ., Chichester, UK... 

Willner and coworkers demonstrated three-dimensional networks of Au, Ag, and mixed composites of Au and Ag nanoparticles assembled on a conductive (indium-doped tin oxide) glass support by stepwise LbL assembly with A,A -bis(2-aminoethyl)-4,4 -bipyridinium as a redox-active cross-linker.8 37 The electrostatic attraction between the amino-bifunctional cross-linker and the citrate-protected metal particles led to the assembly of a multilayered composite nanoparticle network. The surface coverage of the metal nanoparticles and bipyridinium units associated with the Au nanoparticle assembly increased almost linearly upon the formation of the three-dimensional (3D) network. A coulometric analysis indicated an electroactive 3D nanoparticle array, implying that electron transport through the nanoparticles is feasible. A similar multilayered nanoparticle network was later used in a study on a sensor application by using bis-bipyridinium cyclophane as a cross-linker for Au nanoparticles and as a molecular receptor for rr-donor substrates.8... 

Photostimulation of the catalytic activities of bio-imprinted enzymes was studied by Willner and co-workers [25]. The goal of this study was to control the enzymatic activity with light. They linked a photoactive group such as nitropyran to a-chymo-trypsin. The resulting conjugated enzyme was allowed to interact with A -acetyl-L-phenylalanine (as template) in an an aqueous medium. After precipitating the enzyme-template complex, the template was carefully eluted from the enzyme. The catalytic activities of the non-imprinted and imprinted photoactive enzymes were... 

Several animal models of depressive disorders have been studied, and space does not permit detailed review of these findings. Animal models of depression have fallen into three general categories Stress induced, ethologically relevant, and genetic (Machado-Vieira et al., 2004). Of the stress-induced models, learned helplessness, chronic mild sh ess, and forced sw im (behavioral despair) are best characterized (Willner and Mitchell, 2002). 

Patolsky, R, Filanovsky, B., Katz, E., and Willner, I. Photoswitchable antigen-antibody interactions studied by impedance spectroscopy. /. Phys. Chem. B 1998, 2 02, 10359-10367. 

The avidin-biotin procedure has been extensively used in hybridization studies. Since the concentration of all analysed DNAs used is identical, the total concentration of the analysed samples is high. The amplification of the base-mismatch recognition event is necessary to improve sensitivity. The use of oligonucleotide-functionahzed Uposomes or biotin-labelled liposomes as probes for the dendritic amphfication of DNA-sensing processes was characterized by Willner and co-workers [62] and showed better performance using QCM than impedance spectroscopy measurements. 

Most of the electrochemical phenomena occur in size regimes that are very small. The effects of size on diffusion kinetics, electrical double layer at the interface, elementary act of charge transfer and phase formation have recently been reviewed by Petrri and Tsirlina [12]. Mulvaney has given an excellent account of the double layers, optical and electrochemical properties associated with metal colloids [11]. Special emphasis has been given to the stability and charge transfer phenomenon in metal colloid systems. Willner has reviewed the area of nanoparticle-based functionalization of surfaces and their applications [6-8]. This chapter is devoted to electrochemistry with nanoparticles. One of the essential requirements for electrochemical studies is that the material should exhibit good conductivity. 

The use of nanoparticle arrays to generate surface-confined architectures has been extensively studied by Willner and co-workers [6]. The structural motif involves the sequential electrostatic assembly of nanoparticles and the desired molecules on planar electrodes. An ITO substrate is functionalized using an aminosilane molecule to yield a charged surface. Negatively charged citrate-stabilized gold... 

Stellbrink, J., Allgaier, J., Willner, L., et al., 2002. Real time SANS study on head group self-assembly for lithium based anionic polymerizations. Polymer 43 (25), 7101-7109. 

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