Bioconjugation of Noble Metal Nanoparticles and Their Applications to Biolabeling and Bioimaging - From Bioimaging to Biosensors: Noble Metal Nanoparticles in Biodetection - page 18

azide-modiied Au nanoparticles to react with acetylene-modiied
lipases, utilizing the copper (I)-catalyzed 1,2,3-triazole formation
between azides and terminal acetylenes. 38

(A)

(B)

Figure 2.3 Conjugation methods of noble metal nanoparticles with
biomolecules using (A) SMCC and (B) EDC. SMCC is a cross-link
for combination of amine and thiol groups and EDC is a reagent
for combination of amine and carboxylic acid groups to form
amide bonds.

2.2.3 Other Biomolecule Conjugation Methods

Conjugation of noble metal nanoparticles with biomolecules
proceeds not only through the formation of covalent bonds and
electrostatic interactions but also through host-guest systems. The
host-guest interactions can be seen in biomolecule systems such as
antibody-antigen, protein A (or protein G)-immunoglobulin G (IgG)
and biotin-avidin. The advantages of host-guest systems are high
selectivity and speciication and the strong interaction between
the host and guest substrates. In these systems, the orientation
and conformation of biomolecules does not undergo any change,
and thus, the biomolecules can keep their biological functions and
bioactivities. For examples, biotin-modiied DNA, peptides, and
antibodies can speciically target avidin-coated Au nanoparticles. 43,44
Recently, similar conjugating strategies (inorganic metal ion-
biomolecules systems) with speciic and strong interactions were
used to attach biomolecules on noble metal nanoparticles. A metal