Biomedical Engineering Reference
In-Depth Information
FIGURE 4.6
Agarose gel electrophoresis of IOMNP (Ocean NanoTech's catalog # SHP5 and
SHP10 for 5 and 10
nm diameter with carboxyl group on the surface) with and without conjugated
BSA.
Courtesy of Ocean NanoTech.
(For color version of this figure, the reader is referred to the
online version of this topic)
Thiol-modified biomolecules are used for the preparation of nanobiosen-
sors. Thiols, when exposed to metallic gold, form a SAM.
47,86-89
This assembly
works on metallic NMs in a similar way.
A novel method for fabrication of a diphtheria potentiometric immunosen-
sor has been developed by means of self-assembling compound NMs to a thiol-
containing sol-gel network.
90
In this study, the following protocol was used to
create the NMs with self-assembled monolayers.
4.5.1 Preparation of SAMs on NMs for Protein Detection
SAMs on NMs may be prepared following ordinary protocols generally applied
to formation on other substrates. SAMs may be formed from thiols or silanes.
A general protocol used for AuNP and silver nanoparticle (AgNP) is described.
This protocol may be adopted for other systems with optimization.
4.5.1.1 Chemicals
(1)
AuNPs.
(2)
AgNPs.
(3)
3-Mercaptopropyltrimethoxysilane (MPS).
(4)
Aqueous NaOH.
(5)
Diphtheria antigen.
(6)
Antibody against diphtheria.
(7)
Reference electrode.
(8)
Gold electrode.
(9)
0.2 mol/L glycine-hydrochloric acid (Gly-HCl) buffer.
4.5.1.2 Protocol
(1)
Immerse a clean gold electrode in an MPS sol-gel solution to assemble a
silica sol-gel monolayer.
(2)
Dip the silica sol-gel monolayer into aqueous NaOH to polymerize into a
two-dimensional sol-gel network (2D network).
