Bioconjugation of Noble Metal Nanoparticles and Their Applications to Biolabeling and Bioimaging - From Bioimaging to Biosensors: Noble Metal Nanoparticles in Biodetection - page 16

Au nanoparticles speciically and selectively recognize DNA targets
of interest. Subsequently, the targeted DNAs produce signals (light
scattering) detected by optical measurement. The colors observed
from the light scattering of noble metal nanoparticles depend on
their compositions, shapes, and diameters. 36 If DNAs are conjugated
with different noble metal nanomaterials, DNA-conjugated particles
can detect many different DNAs of interest at the same time because
of the different colors originating from distinct noble nanoparticles.
Taton et al . had shown a two-color DNA sandwich assay. 37 Different
diameter gold nanoparticle probes were used to give speciic
targeting for detection of interesting subjects on a chip. The signals
from different nanoparticles with distinct color provided clear
detection for targeted subjects.

Figure 2.2 DNA detection assay using light scattering. The a-DNA-
conjugated Au nanoparticles can speciically and selectively
bind to b-DNA after adding complementary a ′ b ′ -DNA, but
c-DNA is not able to hybridize with a-DNA-conjugated Au
nanoparticles. Thus, the site of b-DNA can observe responded
color using light scattering, while the site of c-DNA has no
signal.

2.2.2 Protein, Peptide, and Antibody Conjugation

Proteins, peptides, and antibodies have been extensively utilized
to conjugate with noble metal nanomaterials for biomedical
studies. 38-40 To directly conjugate with noble metal nanoparticles,
biomolecules may use their residual thiol groups to attach to the