Electrostatic binding

This work was supported by the National Science Foundation (CHE 9102657). The CFKR is supported jointly by the Biotechnology Research Resources Division of the NIH (RR00886) and by The University of Texas at Austin. 

Center for Fast Kinetics Research The University of Texas at Austin, Austin, Texas 78712, U.S.A. 

Harriman, A. Energy Resources Through Photochemistry and Catalysis (ed. Gratzel, M.), p. 163, Academic Press, London (1983). 

Crown Ethers and Cryptands, Royal Society of Chemistry, London (1991). 

Davila, J. Harriman, A. Milgrotn, L.R. Chem. Phys. Lett.,136, 427 (1987) 

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SPV- from the electric field of the polycation, which leads to a first-order back ET kinetics. Since the addition of NaCl interferes with the electrostatic binding of SPV- by QPh-14, SPV- can escape into the bulk phase by diffusion. Therefore, the back ET occurs via a bimolecular process when NaCl is added. 

Oppositely charged ions are attracted to each other by electrostatic forces and so will not be distributed uniformly in solution. Around each ion or polyion there is a predominance of ions of the opposite charge, the counterions. This cloud of counterions is the ionic atmosphere of the polyion. In a dynamic situation, the distribution of counterions depends on competition between the electrostatic binding forces and the opposing, disruptive effects of thermal agitation. 

Electrostatic binding Groove binding Intercalative binding Fig. 5 Schematic representation of various binding modes of small molecules to DNA... 

Although non-covalent interactions of anions are one of the most actively explored areas of supramolecular chemistry [15], the anion sensing and recognition have up to now relied primarily on electrostatic binding or hydrogen bonding to the receptor [16,54-61]. However, recent UV-Vis and NMR spectral studies clearly reveal that complex formation takes place in the solutions between halides and neutral olefinic and aromatic it-acceptors such as those in Fig. 3 [23,62],... 

The method for creating acceptor sink condition discussed so far is based on the use of a surfactant solution. In such solutions, anionic micelles act to accelerate the transport of lipophilic molecules. We also explored the use of other sink-forming reagents, including serum proteins and uncharged cyclodextrins. Table 7.20 compares the sink effect of 100 mM (5-cyclodextrin added to the pH 7.4 buffer in the acceptor wells to that of the anionic surfactant. Cyclodextrin creates a weaker sink for the cationic bases, compared to the anionic surfactant. The electrostatic binding force between charged lipophilic bases and the anionic surfactant micelles... 

By the immobilization results it has been possible to know that the RML shows, at neutral pH, a total positive charge. This positive charge doesn t permit to immobilize this enzyme by electrostatic binding forces that involving amino groups. 

Owing to their unique (tunable-electronic) properties, semiconductor (quantum dots) nanocrystals have generated considerable interest for optical DNA detection [12], Recent activity has demonstrated the utility of quantum dot nanoparticles for enhanced electrical DNA detection [33, 34, 50], Willner et al. reported on a photoelectrochemical transduction of DNA sensing events in connection with DNA cross-linked CdS nanoparticle arrays [50], The electrostatic binding of the Ru(NH3)63+ electron acceptor to the dsDNA... 

J. Shen and J. Wendoloski, Electrostatic binding energy calculation using the finite... 

Adsorption the process of solute accumulation at a cell membrane surface. For cations, this usually involves electrostatic binding to anionic groups on the cell membrane. 

The redox groups can be introduced by coordination, electrostatic binding or covalent attachment to the polymer backbone. 

A large number of examples of redox polyelectrolyte monolayers have been reported [42[. Anson described the adsorption of poly(acrylic acid) onto glassy carbon with electrostatic binding of Ru(NH3)6 and Co(NH3)6 ions from solution [43]. Finklea [44] adsorbed poly(4-vinyl-I-methyl-pyridinium methylsulfate) on self-assembled mercapto-undecanoic self-assembled monolayer (SAM) on gold electrodes to... 

The first report of surface-immobilized dendrimers was in 1994 [54]. Subsequently, our research group showed that the amine-terminated PAMAM and PPl dendrimers could be attached to an activated mercaptoimdecanoic acid (MUA) self-assembled monolayer (SAM) via covalent amide linkages [55, 56]. Others developed alternative surface immobilization strategies involving metal com-plexation [10] and electrostatic binding [57]. These surface-confined dendrimer monolayers and multilayers have found use as chemical sensors, stationary phases in chromatography, and catalytic interfaces [41,56,58,59]. Additional applications for surface-confined dendrimers are inevitable, and are dependent only on the synthesis of new materials and the development of clever, new immobilization strategies. 

Acetylation of slides prevents nonspecific, electrostatic binding of DNA probe to the cells. It is important that the acetylation solution be prepared immediately before use, with stirring, and that it not be reused. Prepare as follows add O.IM triethanolamine to a Coplin jar with a magnetic stirring bar. As stirring proceeds, add sufficient acetic anhydride to give a final concentration of 0.25% (v/v). 

In the second approach, M-POMs containing protons as counter ions were used to fulfill electrostatic binding of M-POM to the support in one stage via the formation of anion-cation pairs (Eqs. 3 and 4) ... 

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