Gold, interactions involving

Adsorption is the simplest method of immobilization as it does not involve the formation of covalent bond formation between the ODN and the surface (see Fig. 7.1b). Instead, it relies on electrostatic interactions between negatively charged sugar-phosphate skeleton of DNA and positively charged electrode surface and/or interactions involving the nucleobases and the surface. Physical adsorption is often achieved on electrochemical oxidized carbon electrodes [11-14] (HOPGE, GCE, CPE) and less often on gold [15] or ITO [16] surfaces. For examples, cationic polymers, such as chitosan, have... 

In order to understand better the namre of the interactions involved in nanofibre formation, attenuated total reflection Fourier-transform infrared (FTIR) spectroscopy analyses were conducted on pure MEA and a MEA/HAUCI4 system, before reduction of the gold precursor. The disappearance of the signal at 2,554.3 cm (corresponding to the vibration of the thiol) after addition of gold precursor confirms the formation of an Au-S bond in the system, as shown in Fig. 12. Moreover, the appearance of a new signal at 3,648 cm and the shift observed for the OH vibration frequency reveal the presence of hydrogen bonds in the fibres [62, 63]. 

Large differences between the interfacial properties of ds and ssDNAs observed earlier by capacitance measurements [10, 37] suggested that a.c. impedance measurements could be used to detect DNA hybridization on electrodes [433, 434] (Sect. 12.8.). A three-component ODN system on a gold electrode (involving avidin-biotin interactions) was used to detect specific DNA sequences by means of faradaic impedance spectroscopy [435]. Impedance spectroscopy does not seem, however, to be the most convenient method for the DNA biosensor faster and simpler voltam-metric or chronopotentiometric methods will probably be more convenient. Gon-ductivity of the perfect DNA, contrasting with a loss of conductivity in duplexes with mismatched bases, may be of use in... 

The ions Ga, In, T1, Sn and Pb have the electronic configurations Core (n-l)d ns. The three p-orbitals are therefore vacant and can accept electrons from the filled 7i-orbitals of the arene. Transition elements are also capable of coordination with arenes (p. 204), but here there are important additional interactions involving the metal d-orbitals. Copper(I), silver(I) and gold(I) form... 

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