Au-Thiol Binding

A similar immobilization methodology has been used to develop a DNA-sensing platform for Helicobacter pylori [13]. Rigid conducting gold nanocomposites have been also modified with this strategy. 

Shen et al. [16] have recently reported the development of an electrochemical DNAzyme biosensor based on DNA-Au bio-bar code amplification, which provides a platform for fabrication of sensors for analysis of many small molecules, especially for metal ions. For example, a specific DNAzyme for Pb + was immobilized onto an Au electrode surface via a thiol-Au interaction, taking advantage of cataljAic reactions of a DNAzyme upon its binding to Pb + and the use of DNA-Au bio-bar codes to achieve signal enhancement [16]. The presence of gold nanoparticles, enhancing the active surface 

Thin gold films deposited by low pressure gold sputtering or electrochemical deposition can provide a highly sensitive and reproducible electrode for the preparation of DNA biosensors without the requirement of the cleaning step. However, the thin gold film directly sputtered on a substrate very easily peels off 

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Red cells provide a useful model for studying the likely movement of gold into and out of cells. Itwas shown that Et3PAuCl moving into red cells binds to glutathione and hemoglobin [84, 85] providing ancillary evidence for the sulfhydryl shuttle. Similarly, [Au(CN)2] has been shown to enter red cells by the sulfhydryl shuttle and its uptake can be blocked by alkylation of membrane thiols [32]. 

Yu et al. prepared 48, bound to an Au(lll) surface by a thiol on the biphenyl end, then deprotected on the bipyrimidine end to expose a thiol to bind an Au nanoparticle. Rectification was measured by scanning tunneling spectroscopy (STS), and it could be reversed by the addition of acid, which protonated the pyrimidine rings, converting them from donor to acceptor [121]. Yu s group has also inverted the attachment of a rectifier, as shown with 49 and 50, and confirmed that the rectification direction reversed [122]. This was recently verified by STM-BJ measurements [123]. 

Cysteine, HS-CH2-CH(NH2)-COOH, binds covalently to gold due to the thiol group. When depositing enantiomeric pure (L-cysteine or D-cysteine) on Au( 110) at... 

Bifunctional linkers bearing functional groups like thiols, disulfides or phosphines are widely used for covalent binding between Au NPs and biomolecules. For example, Au NPs stabilized with a functionalized polysiloxane shell have been used for covalent binding to biomolecules [152]. 

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