Bioconjugation of Noble Metal Nanoparticles and Their Applications to Biolabeling and Bioimaging - From Bioimaging to Biosensors: Noble Metal Nanoparticles in Biodetection - page 15

2.2.1 DNAConjugation
Noble metal nanoparticle-DNA conjugates, especially Au nanoparticle-
DNA conjugates, have been utilized in many applications, including
hybridization sensing, 32 self-assembly, 33 and delivery. 34 Covalent
attachment of DNA to noble metal nanoparticles is straightforward
and generally accomplished by thiol linkers. 35 The DNA are usually
modiied at the terminal base with thiol groups, and the thiol groups
can directly react with the nanoparticles and to form covalent Au-S
bonds (Fig. 2.1). The length of DNA can affect the conjugated
numbers on the particle surface. The density of the conjugated DNA
numbers also affects the stability in solvents. The DNA-conjugated
noble metal nanoparticles can be stable in aqueous solution under
higher salt concentrations as the conjugated DNA helps them resist
salt effects.
Figure 2.1 Conjugation of Au nanoparticles with thiol-modiied DNA.
Short DNA and long DNA affect the conjugated numbers on the
nanoparticle surface.
Oligonucleotide-conjugated noble metal nanoparticles can
hybridize with complementary oligonucleotide. This idea is used
to design DNA detection assays. For example, light scattering
techniques are employed to demonstrate the speciic binding to
speciic DNA (Fig. 2.2). This scenario is that the DNA-conjugated