Phan Thi Thanh Binh K52 Advanced Program Chemistry
VIETNAM NATIONAL UNIVERSITY, HANOI
HANOI UNIVERSITY OF SCIENCE
FACULTY OF CHEMISTRY
Phan Thi Thanh Binh
STUDY ON SELECTED SYNTHESES OF GOLD
NANOPARTICLES
Submitted in partial fulfillment of the requirements for the degree of
Bachelor of Science in Chemistry
(Advanced Program)
Hanoi - 2012
Phan Thi Thanh Binh K52 Advanced Program Chemistry
VIETNAM NATIONAL UNIVERSITY, HANOI
HANOI UNIVERSITY OF SCIENCE
FACULTY OF CHEMISTRY
Phan Thi Thanh Binh
STUDY ON SELECTED SYNTHESES OF GOLD
NANOPARTICLES
Submitted in partial fulfillment of the requirements for the degree of
Bachelor of Science in Chemistry
(Advanced Program)
Hanoi - 2012
Phan Thi Thanh Binh K52 Advanced Program Chemistry
ACKNOWLEDGEMENT
I would like to express my gratitude Assoc. Prof. Dr. Tran Thi Nhu Mai for her
supervisor and guidance throughout all of my researches.
A very special thanks goes out to Professor Catherine J. Murphy and her group's
members, who gave truly help the progression and smoothness of the internship
program in University of Illinois at Urbana Champaign.
I am also thankful all of other members of Laboratory of Organic Catalyst for
their helps during my working time.

2.1 Seeded - growth method to synthesize gold nanorods 36
2.2 Hydrolysis Stober method to silica - coating gold nanorods 36
2.3 Hydrothermal method to synthesize gold nanoparticles template 37
2.4 Characterization Methods 38
CHAPTER 3: RESULTS AND DISCUSSIONS 44
3.1 PURPOSES 44
3.2 SYTHESIS AND CHARACTERIZATION OF GOLD NANORODS 45
3.2.1 The effects of AgNO3 volume on obtained gold nanorods 46
3.2.2 Effects of PEG - coating and silica - coating on gold nanoparticles 48
3.3 SYNTHESIS AND CHARACTERIZATION OF AU/SI (Au/Si_01) 53
3.2.1 N2 adsorption-desorption measurements 55
3.2.2 TEM, EDX and AAS methods 56
3.4 PROSPECTIVE APPLICATIONS 58
3.4.1 Gold nanorods 58
3.4.2 Au/Si material 59
CONCLUSION 61
REFERENCE 62
Phan Thi Thanh Binh K52 Advanced Program Chemistry
LIST OF FIGURES
Figure 1: Exponential growth in the number of publication on gold nanotechnology and nano-
medicine over the two past decades.[6] 11
Figure 2: Conversion of glucose to gluconic acid in alkaline aqueous solution 12
Figure 3: Approaches of loading/unloading therapeutics 17
Figure 4: Loading drugs into the interior of gold nanoparticles 18
Figure 5: Scheme of sensing layer preparation using both peptide and antibody 19
Figure 6: Gold nanodendrites 20
Figure 7: Gold Nanorods [21] 21
Figure 8:Sharpened nanorods [22] 21
Figure 9: Nanocages/nanoframes 22
Figure 10: Nanoshells [24] 22

Figure 38: EDX spectrum of Au/Si 58
Figure 39: Typical properties and applications of gold nanorods [43] 59
Figure 40: Products containing calcium gluconate 60
LIST OF TABLES
Table 1: Gold nanoparticles in photothermal therapy applications 15
Table 2: Summary of synthetic approaches to obtain various gold nanostructures 24
Table 3: Outline of relation between stability and zeta-potential 40
Table 4: Data of rainbow gold nanorods 46
Table 5: BET - data of Au/Si_01 55
Phan Thi Thanh Binh K52 Advanced Program Chemistry
INTRODUCTION
Normally, we also know that pure gold is a transition metal in the group 11 of
periodical table. It has a very high melting point and shows the nature as one of the
least reactive metals. However, it exhibits a beautiful appearance, amazing malleability
and ductility, of course, good conductivity. That means why gold have been more
widely used to craft expensive ornaments or gild electronic accessories than apply on
chemical field.
However, in the recent researches, the scientists have discovered that gold on
nanoscale represents a huge number of predominant effects that are full of promises to
play the role of aurotherapy, photothermal argents, and especially catalysis, optical
materials and biomedicine such as drug therapy or biosensor.
In fact, Murphy et al.[1] and Nikoobakht and El-Sayed[2] have been successful
to demonstrate a colloid method to synthesize mono - disperse nanorods at high yield
based on seeded growth method. After that, to increase the biological compatibility,
nanorods will be coated and functionalized by other materials, generally for instance, a
variety of silicates or polymers, which have the functional groups to be similar to acid
amines, enzymes such as thiolate, amines, carboxylate etc. In the first part of this
research, I have already prepared nanorods based on seeded - growth theory in the
Phan Thi Thanh Binh K52 Advanced Program Chemistry
presence of silver and cationic surfactant CTAB and . Then the Stober method was

particle size is an important consideration, many other factors such as geometry,
composition, oxidation state, and chemical/physical environment can play a role in
determining NP reactivity. However, the exact relationship between these parameters
and NP catalytic performance may be system dependent, and is yet to be laid out for
many nanoscale catalysts. Clearly, a systematic understanding of the factors that
control catalyst reactivity and selectivity is essential if trial and error methods are to be
avoided.
1.2 OVERVIEW OF GOLD NANOPARTICLES
The first scientific report describing the production of colloidal gold
nanoparticles was published in 1857 when Michael Faraday found that the ‘‘fine
particles’’ formed from the aqueous reduction of gold chloride by phosphorus could be
stabilized by the addition of carbon disulfide, resulting in a "beautiful ruby fluid".
Actually, the Human has a huge step up to approach the gold nanoparticles. Nowadays,
most colloidal synthetic methods for obtaining gold nano particles follow a similar
strategy, whereby solvated gold salt is reduced in the presence of surface capping
ligands which prevent aggregation of the particles by electrostatic and/or physical
repulsion.
Gold nanoparticles have been used
in biomedical applications since their first
colloidal syntheses more than three
centuries ago. Actually, over the past two
decades, their beautiful colors and unique
electronic properties have also attracted
serious attention due to their historical
applications in art, medicine and current
applications in enhanced optoelectronics
and photovoltaics. In spite of their modest
alchemical beginnings, gold nano-particles
possess physical properties that are
significantly different from both small

are supported on base metal oxides or carbon, very active catalysts are produced. One
of the potential advantages that Au catalysts offer compared with other precious metal
catalysts is lower cost and greater price stability, Au being substantially cheaper (on a
weight for weight basis) and considerably more plentiful than Pt. A huge number of
publications have exhibited the various application of gold nanoparticles as the role of
catalyst such as: pollution and emission control, chemical processing of bulk and
specialty chemicals, clean hydrogen production for the emerging hydrogen economy
including fuel cells, sensors for detecting pollutants [8].
Chemical Processes
Gluconic acid is an important food and beverage additive, and is also used as a
cleansing agent. The German group of researchers has suggested that the oxidation of
glucose to gluconic acid can be maintained at high activity and selectivity using a
stirred tank reactor for up to 110 days with a nanoparticulate Au on alumina catalyst
prepared by deposition precipitation with urea and incipient wetness methods (Fig. 2)
[9].
Figure 2: Conversion of glucose to gluconic acid in alkaline aqueous solution
Another differential of glucose - methyl gluconate, which plays an important
role as a solvent for semiconductor manufacturing processes, as a building block for
cosmetics, and as a cleaner for boilers and metals, has been also demonstrated a
process using Au catalyst with a capacity tons of month. So the methyl gluconate can
be synthesized directly by one - step production:
2 2 2 2 2
2HOCH CH OH MeOH O OHCH COOMe H O
+ + → +
Phan Thi Thanh Binh K52 Advanced Program Chemistry
The first application of Au/Pt catalyst in the vinyl acetate monomers (VAM)
manufacturing has been established. In the industrial scale, VAM is produced from
ethene, acetic acid, and oxygen using Au–Pd catalysts:
2 2 3 2 2 2 2 3 2
1

. Au is also particularly promising for color-change sensors used
for monitoring components of body liquids.
Phan Thi Thanh Binh K52 Advanced Program Chemistry
Optical properties - Chemical sensors and Imaging
Strong plasmon absorption and sensitivity to local environment have made
metal nanoparticles attractive candidates as colorimetric sensors for analytes including
DNA, metal ions, and antibodies [10]. These visible color changes are due to metal
nanoparticle aggregation, which in turn affects the plasmon coupling and induced
dipoles. Taking the example of use of gold nanoparticles as selective sensors for Li
+
[11], this solution-based sensor utilizes nanoparticles functionalized with a ligand that
binds to gold via a thiol at its back end, and a phenanthroline derivative at the front end
to selectively bind to Li
+
as a bidentate ligand.
Resonant Rayleigh scattering from metallic nanoparticles is a unique
characteristic of nanoscale metals. Due to the fact of the sensitivity of these plasmon
resonant particles (PRPs) to local chemical environment, refractive index, and
nanoparticle size and shape, resonant Rayleigh scattering from gold nanoparticles,
made by colloidal or lithographic techniques, has been utilizing for biological and
chemical analyses [12]. Moreover, the applications have been straighten in the elastic
light scattering from metallic nanoparticles that is measured to infer nanoparticle
position, local environment, or (in the case of nanorods) relative orientation.
Inelastic visible light scattering from metal nanoparticles is also a useful means
to gain chemical information about the nanoparticle’s environment. Surface-enhanced
Raman scattering (SERS) is a powerful analytical tool for determining chemical
information for molecules on metallic substrates on the 10 - 200 nm size scale. Raman
vibrations of molecules are in general very weak; but in the presence of metals (copper,
silver, gold) with nanoscale roughness, the molecular Raman vibrations excited by
visible light are enhanced by orders of magnitude.

properties make gold nanoparticles promising candidates for photothermal therapy of
cancer and various pathogenic diseases. The common use of gold nanoparticles in
photothermal therapy are abundant in the literature is sum up in Table 1.
Table 1: Gold nanoparticles in photothermal therapy applications
Nanoform Particle size (nm) Available region Applications
Gold - silica
nanoshells
110 - 150 Vis - NIR ablating various cancerous
cell lines in vitro and treating
of cancer in animal models in
vivo
Phan Thi Thanh Binh K52 Advanced Program Chemistry
Nanorods 33.7 ± 3.5 x
9.1±1.4,
50 x 12, 13x 47 etc.
plasmonic
phototherapeutis
ablate tumors in mouse
models of colon cancer and
squamous cell carcinoma.
Nanocages 48.0 ± 3.5 NIR-absorbing Photothermal therapeutic
agents was demonstrated both
in vitro and in vivo.
Hollow gold
nanoshells
415 ± 2.3 NIR To be effective photo-thermal
therapeutics in both in vitro
and in vivo models.
Gold - gold sulfide
nanoparticles

agent via a cleavable linker (f). In this case, the gold surface is already passivated with
various functional groups and the drug attachment proceeds to the outermost layer on
top of the particles. Release can be triggered by hydrolysis, light, heat, and/or pH
changes. But in the case of (g), charged biomolecules ( e.g. DNA or siRNA) can be
easily attached to the surfaces of complementary charged gold nanoparticles by
electrostatic-conjugation or the related layer-by-layer (LbL) coating. Release of
payload can be triggered by the use of charge-reversal polyelectrolytes combined with
pH change. Finally, drug molecules are incorporated into the matrix of a thermo-
sensitive, crosslinked polymer (h). Then, release can be triggered by the photothermal
heating by gold nanoparticles also incorporated into the matrix.
Phan Thi Thanh Binh K52 Advanced Program Chemistry
Furthermore, under the appropriate excitement, the loading inside the
nanoparticles could be happened by some ways.
Figure 4: Loading drugs into the interior of gold nanoparticles
In the detail:
(a) Gold nanocages (hollow gold cubes with porous walls) are functionalized
with a thermosensitive polymer brush layer at their exterior surface to cage drug
molecules in their interior. Laser irradiation induces local heat flux and thus, collapse
of the thermo-sensitive polymer to release the caged drug molecules.
(b) Gold nanocages with the drugs dispersed into a thermosensitive material in
the interior of the nanoparticles. Laser irradiation results in phase-change (melting) of
the thermosensitive ‘‘filler’’ and thus enhances drug release.
(c) A gold nanoshell covers a liposome carrying drugs in its interior. Gold
nanoshells absorb light and convert it to heat and these events result in disintegration
and clearance of the carrier, as well as release of its encapsulated drugs.
Optional applications
Besides the great potential for gold nanoparticles as drug delivery carriers, they
have also been used to stabilize and enhance the efficiency of other drug delivery
carriers such as liposomes and microcapsules. Moreover, gold nanoparticles were
incorporated in various types of materials to fabricate gold-containing devices for drug

diverse biomolecules when a target - specific sensing layer is formed in the surface of
structure [17].
Figure 6: Gold nanodendrites
In addition, the Au microelectrode sensor has been developed for detection of Hg (II)
in a low concentration as well. In short speaking, a simple and reproductile carbon
microelectrode array (CMA), designed to eliminate diffusive interference among the
microelectrodes, has been fabricated and used as a frame to build a gold nicroelectrode
array (GMA) sensor [18].
1.2.2 Synthesis and Functionalization
A variety of synthetic methods and gold nanoparticles forms
In historical sequence, interest in the shape-controlled synthesis of gold
nanostructures began booming in the early 1990's when Masuda et al. and Martin [19]
developed techniques to prepare gold nanorods by electrochemical reduction into
nanoporous aluminium oxide membranes. However, in the beginning, the obtained
nanorods had mono - disperse structures relatively, but because of the low yield and
large diameter (>100nm), the optical response is difficult to discern and largely
Phan Thi Thanh Binh K52 Advanced Program Chemistry
dominated by multipolar plasmon resonance modes [20]. This negative effects had
been improved by Wang and coworker later by electrochemical oxidation of a gold
plate electrode in the presence of cationic, quaternary ammonium surfactants (CTAB
or TOAB). The resulting particles synthesized by this method has only ~ 10nm in
diameter. It also existed many disadvantages needed to upgrade, though.
In general based on previous
achievements and in particularly seeded growth
method, Murphy et al. and Nikoobakht and El-
Sayed later demonstrated a colloidal growth
method to produce mono - disperse gold
nanorods in high yield (Fig. 7). In this method,
small (~1.5 nm diameter) single-crystal seed
particles, produced from the reduction of

reduction of silver nitrate, based on a phenomenon
known as galvanic replacement, whereby more noble
metal ions (e.g. Au, Pt) spontaneously oxidize the
surface atoms of a less noble metal (e.g. Ag, Cu) with
concomitant reduction of the more noble metal [23].
Figure 9:
Nanocages/nanoframes
Figure 10: Nanoshells [24]
Silica-gold coreshell nanoparticles, or
gold nanoshells (Fig. 10), have recently attracted
much attention, for example, Aden and Kerber
(1951) or Halas and his coworkers (1998), due to
their interesting optical properties and numerous
biomedical applications. In a typical synthesis,
silica nanoparticle cores are synthesized by the
base-catalyzed condensation of orthosilicate (i.e. Stober hydrolysis) and functionalized
with an amine - terminal silane. Small, anionic gold nanoparticles synthesized from the
aqueous reduction of chloroauric acid by tetrakis (hydroxymethyl) phosphonium
chloride (THPC) are electrostatically adsorbed onto the surfaces of the silica cores and
added to a solution of mildly reduced chloroauric acid. When formaldehyde is added to
the solution, the adsorbed gold particles serve as nucleation sites for the further
reduction of gold around the silicacore, subsequently forming a conformal nanoshell.
Caruso and coworkers obtained hollow gold nanospheres by calcination or
dissolution of polystyrene–gold core–shell nanoparticles (Fig.11). In this case,
polystyrene nanospheres were bounded by polyelectrolyte multilayer films and 4 -
(dimethylamino) pyridine (DMAP) stabilized
gold nanospheres (approx. 6 nm diameter) were
electrostatically adsorbed to the
polyelectrolyte surface. After that,
Phan Thi Thanh Binh K52 Advanced Program Chemistry

seeds added to the growth solution, obtaining cubes with edge lengths ranging from 38
± 7 nm to 269 ± 18 nm width at high yield up to 95%.
Besides, nano - gold has been found in other various shapes and sizes such as
tetrahexahedra, rhombic dodecahedra, obtuse triangular bipyramids (Fig. 14)
synthesized by a number of methods.
Figure 14: Complex nanostructures
In brief, Table 2 covered approaching methods to make gold nanoparticles:
Table 2: Summary of synthetic approaches to obtain various gold nanostructures
Phan Thi Thanh Binh K52 Advanced Program Chemistry
Au nanoform Approached methods Authors
Nanospheres Citrate - mediate reduction J. Turkevich at al. (1951)
G.Frens (1973)
Nanorods (colloidal) Seeded growth (CTAB) C.J. Murphy (2001)
B. Nikoobak & El-Sayed (2003)
Nanoshells Overgrowth of core - bound particles N.J. Halas (1998)
Hollow nanospheres
Overgrowth of core - bound particles,
galvanic displacement Z.Liang (2003)
H. - P. Liang & L. Jiang (2005)
Nanocages/frames
PVP - stabilized polyol, galvanic
displacement Y. Xia (2002, 2006)
Nanocubes/octahedra
PVP - stabilized polyol, seeded
growth (CPC/CTAC) W. Niu (2008), Jang (2010)
Icosahedra/tetrahedra
PVP - stabilized polyol, seeded
growth (CTAC) F. Kim (2004)
J. Zhang (2008, 2010)
Nanoprisms Biosynthesis seed growth (CTAB) S. Shankar (2004)