Adsorption onto gold

Fig. 6 Average coverage of unmodified hatched bars) and thiol-modified solid bars) homo-OND films after one hour adsorption onto gold surfaces in 1M KH2PO4. The ratio between both bars indicates the ability of nonspecific binding to interfere with specific thiol binding for each sequence, i.e. the relative strength of nonspecific adsorption for each OND [24]...

Fig. 12.2. An increase of mass leads to an increase of the resonance frequency of elastic mechanic oscillator (left). Similar principle is used for detection of mercury vapour adsorption onto gold electrode of a quartz resonator (right).

In a related study, the authors used self-assembled DNA-polymer conjugates composed of hydrophilic DNA and hydrophobic polymer segments that had been modified with disulfide bridges to facditate their adsorption onto gold substrates leaving hydrophilic DNA exposed to the solution and thus readily available for hybridization, making these chip useful for biosensing applications [103]. 

Caruso, R, et al. Quartz crystal microbalance and surface plasmon resonance study of surfactant adsorption onto gold and chromium oxide surfaces. Langmuir, 1995. 11 p. 1546-1552. 

Studies from this laboratory 24-27 suggest that a sulfur atom is effective to immobilize promoters by irreversible adsorption onto gold and silver electrodes. To date, various sulfur containing promoters are known to give effective promoter-modified electrodes for cytochrome c. In the present paper, surface structures of such promoter-modified electrodes and electrochemistry of cytochrome c at these electrodes have been investigated to better understand the surface functions of such electrodes. 

One particularly novel carrier was reported to consist of 50-70 nm colloidal gold particles of the type often used in cytochemical labeling techniques for microscopy (Pow and Crook, 1993) (Chapter 24). Adsorption of peptide antigens onto gold and subsequent injection of the complex into rabbits in an adjuvant mixture resulted in rapid production of antibody of extremely high titer. The resultant antibodies could be used in immunocytochemistry at dilutions from l-in-250,000 down to l-in-1,000,000, which is orders-of-magnitude beyond the dilutions typically used with lower-titer antibodies. 

Hughes, H. C., Linge, H. G. (1989). Kinetics of gold chloride adsorption onto fresh activated coconut carbon. 

Paclawski, K., Wojnicki, M. (2009). Kinetics of the adsorption of gold(III) chloride complex ions onto activated carbon. 

Recent studies have indicated that the base composition of the OND can affect the efficiency of its ability to bind to a surface. This is most probably a consequence of the different affinity that each base shows for any particular surface [21-24], This has been clearly demonstrated in adsorption studies using homo-ONDs (unmodified and thiol modified) onto gold surfaces [23,24]. It was observed that unmodified homo-ONDs adsorb on gold with relative affinities A > C > G > T (Figs. 5 and 6). When performing competitive adsorption experiments with unmodified and thiol modified ONDs,... 

Fig. 5 FTIR spectra of ssDNA films adsorbed onto gold surfaces from aqueous solutions. Reference spectra for films of individual 5-mer homo-ONDs are shown along with spectra following competitive adsorption from their equimolar mixtures. The corresponding surface density, n, is indicated for each of the homo-ONDs (lO OND cm ) [23]...

Fig. 24a—e. Schematic illustration of monolayers formed by adsorption of mixtures of HStCHyhjOH and HS(CH2))9OH onto gold a pure monolayer of HS(CH2)19OH b-d monolayers containing different mixtures of the two components e pure monolayer of HS(CH2),, OH [175]... 

Au/SBA-15 prepared by anion adsorption onto SBA-15 functionalised by cationic groups also had large gold particles ( 8 nm) and low activity,... 

Several useful schemes for attaching nucleic acid probes onto electrode surfaces have thus been developed [2-8]. The exact immobilization protocol often depends on the electrode material used for signal transduction. Common probe immobilization schemes include attachment of biotin-functionalized probes to avidin-coated surfaces [15], self-assembly of organized monolayers of thiol-functionalized probes onto gold transducers [16], carbodiimide covalent binding to an activated surface [17], as well as adsorptive accumulation onto carbon-paste or thick-film carbon electrodes [15-30]. 

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