Oligonucleotides thiol-modified

Taton et al. used gold nanoparticles functionalized with thiol-modified oligonucleotides to detect the presence of its complementary sequence hybridized on a transparent substrate (Fig. 13.9).16 In comparison to conventional fluorophore probes, this technique is three times more sensitive in discriminating an oligonucleotide sequence with a single basepair mismatch. In addition, signal amplification by reduction of silver ions on the nanoparticles drastically increased the sensitivity of... 

As a class, the cross-linkers used to attach thiol-modified oligonucleotides to solid supports are hetero-bifunctional, meaning that they possess functional groups capable of reaction with two chemically distinct functional groups, e.g., amines and thiols. Hetero-bifunctional cross-linkers can covalently bind two distinct chemical entities that would otherwise remain unre-active towards each other [8]. 

Modification of Aggregates with 5 Thiol Modified Aptamers and Oligonucleotides... 

One of the most common metal surfaces that oligonucleotides have been attached to is gold, which is readily conjugated with thiol-modified materials. 

Baker et al. [95] were the first to report the formation of DNA-SWCNT adducts in solution for DNA hybridization. The DNA-SWCNT complexes were synthesized by reacting oxidized SWCNTs with thionyl chloride and ethylenediamine to form amine-terminated sites, shown in Fig. 14.16. The amines were further reacted with succinimidyl 4-(Af-maleimidomethyl)cyclohexane-l-carboxylate (SMCC) forming maleimide groups which reacted with thiol-modified DNA. To confirm covalent attachment and to test the accessibility of the DNA-modified SWNTs, hybridization studies were conducted using fluorescently labeled DNA oligonucleotide targets. Shortly thereafter, the use of carbodiimide-assisted coupling... 

On the basis of the previous DNA assay, the Mirkin group has developed a silver staining method to enhance the sensitivity. In the sandwich-type format, thiol-modified oligonucleotides were attached to the soUd support These oligonucleotides and the DNA targets hybridized with the DNA functionalized AuNPs. The reduction of the added silver ions was catalyzed by the AuNPs. The concentration of the DNA target was proportional to that of silver, which was visualized with a flatbed scanner. This method was... 

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