Luis Liz-Marzan talks with
ScienceWatch.com and answers a few questions about
this month's Fast Moving Front in the field of
Chemistry. The author has also sent along images of
Article: Synthesis and optical properties of gold
nanodecahedra with size control
Authors: Sanchez Iglesias, A;Pastoriza-Santos,
I;Perez-Juste, J;Rodriguez-Gonzalez, B;de Abajo,
Journal: ADVAN MATER, 18 (19): 2529-+ OCT 4 2006
Addresses: Univ Vigo, Dept Quim Fis, Vigo 36310,
Univ Vigo, Dept Quim Fis, Vigo 36310, Spain.
Univ Vigo, CSIC, Unidad Asociada, Vigo 36310, Spain.
UPV EHU, CSIC, Ctr Mixto, San Sebastian 20080, Spain.
Donostia Int Phys Ctr, San Sebastian 20080, Spain.
Why do you think your paper is highly
Nanoparticle size and shape control is a hot topic within nanoscience and
nanotechnology. Although chemical methods for the synthesis of gold
nanoparticles have been reported since 150 years ago, and dozens of papers
are still published every month, our report deals with an extremely
controlled production of nanoparticles with highly regular geometry
(decahedrons or pentagonal bipyramids) in a wide range of sizes.
Additionally, the paper demonstrates how to manipulate the crystalline
structure (and, in turn, the shape) of the final nanoparticles, through
proper choice of the initial seeds. Finally, the careful demonstration that
the optical properties of such well-defined, though anisotropic
nanoparticles can be accurately predicted, makes it a round piece of work
in this hot area. In my opinion, this serves as an inspiration to other
researchers in the field.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
The paper describes a new synthesis protocol, which can be (and has already
been) used for nanocrystal size and shape manipulation, by simply tuning
the reaction conditions. This general protocol (seeded growth in
N,N-dimethylformamide (DMF), one of the usual organic solvents for numerous
processes) can thus be used for the fabrication of gold and silver
nanoparticles with variable sizes and shapes and, in turn, with tunable
Would you summarize the significance of your paper
in layman's terms?
Nanotechnology deals with the atom-by-atom manipulation of matter in the
nanometer scale. We use chemical processes to do so in such a way that
nanoscale pieces of gold (or other metals) can be fabricated with pretty
much the same size and a very regular shape (with 10 flat external faces
enclosing a decahedron). These pieces of gold (nanoparticles) are dispersed
in a solvent, so that they do not cluster together and thus their
single-particle properties are preserved. Additionally, by changing the
average size of the particles, the color (optical properties) of such
solutions can be varied at will. These optical properties can be exploited
in a number of applications, for example in ultrasensitive detection of
diseases or contaminants.
How did you become involved in this research and
were any particular problems encountered along the way?
My education was in the field of Physical Chemistry, and in particular in
Colloid Chemistry. My Ph.D. thesis (1989-1992) was already related to the
controlled fabrication of nanomaterials using colloidal solutions. Soon, I
realized that these systems had plenty of possibilities, not only from the
point of view of understanding size-dependent properties, but also with
respect to a wide range of applications where such properties could be
Starting my own research group, which could compete at an international
level, was a hard job because of the low level of funding on R&D in
Spain, when I returned from a postdoctoral stay abroad. The group is
currently well established, both regarding funding and external recognition
by our peers.
Where do you see your research leading in the
The production of monodispersed nanoparticles with well-defined
morphologies is still a challenge in many ways, as well as the controlled
assembly of such nanoparticles, and we shall continue working in these
directions. However, the research of my group is gradually leading toward
more practical applications of the systems and properties we have been
studying for some 12 years now. The design of both localized surface
plasmon resonance (LSPR) biosensors and surface-enhanced Raman scattering
(SERS) substrates, for applications in diagnostics, are currently active
areas of research and we foresee more intensive involvement in these
Do you foresee any social or political implications
for your research?
As indicated above, if we succeed in developing novel diagnostic tools
which are more sensitive or simpler to implement in everyday life, we shall
definitely make a huge social impact. Early detection of cancer or other
infectious diseases can significantly contribute to improve the quality of
life for all citizens. Equally important might be the ultrasensitive
detection of contaminants in the environment or chemical weapons.
Professor Luis M. Liz-Marzán
Departamento de Química Física and Unidad Asociada CSIC
Universidade de Vigo
Vigo, Spain Web
Figure 1: Transmission (TEM, left) and scanning
(SEM, right) electron microscopy images illustrating the morphology of gold
nanodecahedra (pentagonal bipyramids).
Top: Photograph of dispersions of gold nanodecahedra with different
particle sizes (increasing from left to right). Bottom: TEM images of
decahedral Au nanoparticles prepared by seeded growth in DMF, using
different amounts of Au seed solution. The scale is the same in all TEM
Keywords: nanoparticle size and shape control, chemical methods
for the synthesis of gold nanoparticles, decahedrons or pentagonal
bipyramids, anisotropic nanoparticles, N,N-dimethylformamide, tunable
optical properties, production of monodispersed nanoparticles,
well-defined morphologies, localized surface plasmon resonance
biosensors, surface-enhanced Raman scattering substrates.