Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Inve stigation of SERS of orga nic molecule bridge d go ld nanoparticles: Synthesis and
charac terization
Remziye Gü zel 1 *, , 2 3 and Ali Osman Solak 3
1
2 Dum
3 Ankara University, Faculty of Science, Department of Chemistry, Ankara, Turkey
Abstract -We describe the short range SERS effect of AuNP by bridging them with an organic molecule, HS(CH 2 ) 2 CONHPhSH, which
has very low inherent sensitivity of Raman scattering. The nanoparticles are contacted by S(CH 2 ) 2 CONHPhS- linker bridges in which
presence of different heteroatoms and functionalities makes it interesting for characterization by XPS, UV, RAIRS, EIS, TEM, Fluorescence
microscopy and SERS.
In recent years, investigation of nanomaterials, especially
metal nanoparticles, has attracted much importance, because
of their interesting chemical, mechanical and physical
properties and potential applications in nanoelectronic and
optoelectronic devices. Nowadays, much effort has been
committed to fabrication of metal nanocomposites, including
alloys, core-shell and mixed particles, due to their valuable
non-linear optical properties in optical switches [1,2], in
catalysis [3,4] and in surface-enhanced Raman scattering
(SERS) [5]. Nanostructured materials that can be tailored to
achieve greater mechanical properties along with their
electrical, optical, thermal and other functional properties are
essential for future applications in many industry sectors. The
electronic conduction of many different metal/organic/metal
systems has been studied experimentally [6]. The thiol group
forms a strong chemical bond to the gold surface. In the case
of physisorption, the molecule is bound to the surface by
weak Van der Waals forces [7].
In this work, we describe the short range SERS effect of
AuNP by bridging with an organic molecule,
HS(CH 2 ) 2 CONHPhSH, which has very low inherent
sensitivity of Raman scattering. We construct the
AuS(CH 2 ) 2 CONHPhSAu assembly in a step by step fashion
which allows us to follow the route of synthesis
spectroscopically and to investigate the individual SERS
effects of mono nanoparticles on the organic bridge. To
achieve this goal, firstly we describe the monolayer
attachment of mercaptopropionic acid (MPA) to the AuNPs
to construct MPA self assembled gold nanoparticles,
AuS(CH 2 ) 2 COOH. In the second step, the carboxylic acid
terminated self assembled monolayer (SAM) film
surrounding the AuNPs is activated with N-(3-
dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride
(EDC) to bind 4-aminothiophenol (ATP) to the
AuS(CH 2 ) 2 COOH forming a dithiol terminated protective
organic film (AuS(CH 2 ) 2 CONHPhSH). Lastly, Au
nanoparticles are bridged to this structure through the
terminal SH groups to construct the organic film bridged
AuS(CH2) 2 CONHPhSAu assembly. Then, we have
investigated the enhancement of the Raman signals of the
organic wire between metal nanoparticles by the
accumulation of the MPCs and assemblies on the glassy
carbon (GC) surface. The nanoparticles are contacted by -
S(CH 2 ) 2 CONHPhS- linker bridges in which presence of
different heteroatoms and functionalities makes it interesting
for characterization by XPS, UV-Vis, RAIRS, EIS,
Fluorescence microscopy and SERS. We emphasize the
effect of plasmon coupling on the
S(CH 2 ) 2 CONHPhS- bridge between Au and Au
nanoparticles. This effect can be exploited to build new
nanostructure architectures in the fabrication of single
molecule detection biosensors.
Formula
Structure
AuS(CH 2 ) 2 COOH
O
S OH
AuS(CH 2 ) 2 CONHPhSH
O
S NH
AuS(CH 2 ) 2 CONHPhSAu
O
S NH
Figure 1. Formula and structures of MPCs and nanoparticle-organic
molecule assembly forms [1].
I would like to thank Prof. Dr. Ali Osman SOLAK who
presenting us his research laboratory for our experiments
*Corresponding author: 0Tguzel.remziye@gmail.com
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S
SH
6th Nanoscience and Nanotechnology Conference, zmir, 2010 231