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Nguyen T. K. Thanh

Other affiliations: Royal Institution, Aston University, University of Amsterdam  ...read more
Bio: Nguyen T. K. Thanh is an academic researcher from University College London. The author has contributed to research in topics: Nanoparticle & Iron oxide nanoparticles. The author has an hindex of 36, co-authored 114 publications receiving 11390 citations. Previous affiliations of Nguyen T. K. Thanh include Royal Institution & Aston University.


Papers
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TL;DR: It is shown that the data produced here can be used to determine both size and concentration of gold nanoparticles directly from UV-vis spectra, and the precision of various methods are discussed.
Abstract: The dependence of the optical properties of spherical gold nanoparticles on particle size and wavelength were analyzed theoretically using multipole scattering theory, where the complex refractive index of gold was corrected for the effect of a reduced mean free path of the conduction electrons in small particles. To compare these theoretical results to experimental data, gold nanoparticles in the size range of 5 to 100 nm were synthesized and characterized with TEM and UV−vis. Excellent agreement was found between theory and experiment. It is shown that the data produced here can be used to determine both size and concentration of gold nanoparticles directly from UV−vis spectra. Equations for this purpose are derived, and the precision of various methods is discussed. The major aim of this work is to provide a simple and fast method to determine size and concentration of nanoparticles.

2,981 citations

Journal ArticleDOI
TL;DR: A progress report on the biomedical applications of magnetic nanoparticles since 2003 is presented in this paper, with a focus on magnetic actuation for in vitro non-viral transfection and tissue engineering.
Abstract: A progress report is presented on a selection of scientific, technological and commercial advances in the biomedical applications of magnetic nanoparticles since 2003. Particular attention is paid to (i) magnetic actuation for in vitro non-viral transfection and tissue engineering and in vivo drug delivery and gene therapy, (ii) recent clinical results for magnetic hyperthermia treatments of brain and prostate cancer via direct injection, and continuing efforts to develop new agents suitable for targeted hyperthermia following intravenous injection and (iii) developments in medical sensing technologies involving a new generation of magnetic resonance imaging contrast agents, and the invention of magnetic particle imaging as a new modality. Ongoing prospects are also discussed.

1,315 citations

Journal ArticleDOI
TL;DR: The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles.
Abstract: Nanostructures have attracted huge interest as a rapidly growing class of materials for many applications. Several techniques have been used to characterize the size, crystal structure, elemental composition and a variety of other physical properties of nanoparticles. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed. In addition, given that the significance of nanoparticles in basic research and applications is constantly increasing, it is necessary that researchers from separate fields overcome the challenges in the reproducible and reliable characterization of nanomaterials, after their synthesis and further process (e.g. annealing) stages. The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles. Different characterization techniques are classified according to the concept/group of the technique used, the information they can provide, or the materials that they are destined for. We describe the main characteristics of the techniques and their operation principles and we give various examples of their use, presenting them in a comparative mode, when possible, in relation to the property studied in each case.

910 citations

Journal ArticleDOI
TL;DR: Based on protein folding considerations, a pentapeptide ligand, CALNN, which converts citrate-stabilized gold nanoparticles into extremely stable, water-solublegold nanoparticles with some chemical properties analogous to those of proteins, has been designed.
Abstract: Based on protein folding considerations, a pentapeptide ligand, CALNN, which converts citrate-stabilized gold nanoparticles into extremely stable, water-soluble gold nanoparticles with some chemical properties analogous to those of proteins, has been designed. These peptide-capped gold nanoparticles can be freeze-dried and stored as powders that can be subsequently redissolved to yield stable aqueous dispersions. Filtration, size-exclusion chromatography, ion-exchange chromatography, electrophoresis, and centrifugation can be applied to these particles. The effect of 58 different peptide sequences on the electrolyte-induced aggregation of the nanoparticles was studied. The stabilities conferred by these peptide ligands depended on their length, hydrophobicity, and charge and in some cases resulted in further improved stability compared with CALNN, yielding detailed design criteria for peptide capping ligands. A simple strategy for the introduction of recognition groups is proposed and demonstrated with bi...

680 citations


Cited by
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TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

11,752 citations

Journal ArticleDOI
TL;DR: The advent of AuNP as a sensory element provided a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.
Abstract: Detection of chemical and biological agents plays a fundamental role in biomedical, forensic and environmental sciences1–4 as well as in anti bioterrorism applications.5–7 The development of highly sensitive, cost effective, miniature sensors is therefore in high demand which requires advanced technology coupled with fundamental knowledge in chemistry, biology and material sciences.8–13 In general, sensors feature two functional components: a recognition element to provide selective/specific binding with the target analytes and a transducer component for signaling the binding event. An efficient sensor relies heavily on these two essential components for the recognition process in terms of response time, signal to noise (S/N) ratio, selectivity and limits of detection (LOD).14,15 Therefore, designing sensors with higher efficacy depends on the development of novel materials to improve both the recognition and transduction processes. Nanomaterials feature unique physicochemical properties that can be of great utility in creating new recognition and transduction processes for chemical and biological sensors15–27 as well as improving the S/N ratio by miniaturization of the sensor elements.28 Gold nanoparticles (AuNPs) possess distinct physical and chemical attributes that make them excellent scaffolds for the fabrication of novel chemical and biological sensors (Figure 1).29–36 First, AuNPs can be synthesized in a straightforward manner and can be made highly stable. Second, they possess unique optoelectronic properties. Third, they provide high surface-to-volume ratio with excellent biocompatibility using appropriate ligands.30 Fourth, these properties of AuNPs can be readily tuned varying their size, shape and the surrounding chemical environment. For example, the binding event between recognition element and the analyte can alter physicochemical properties of transducer AuNPs, such as plasmon resonance absorption, conductivity, redox behavior, etc. that in turn can generate a detectable response signal. Finally, AuNPs offer a suitable platform for multi-functionalization with a wide range of organic or biological ligands for the selective binding and detection of small molecules and biological targets.30–32,36 Each of these attributes of AuNPs has allowed researchers to develop novel sensing strategies with improved sensitivity, stability and selectivity. In the last decade of research, the advent of AuNP as a sensory element provided us a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.37 Figure 1 Physical properties of AuNPs and schematic illustration of an AuNP-based detection system. In this current review, we have highlighted the several synthetic routes and properties of AuNPs that make them excellent probes for different sensing strategies. Furthermore, we will discuss various sensing strategies and major advances in the last two decades of research utilizing AuNPs in the detection of variety of target analytes including metal ions, organic molecules, proteins, nucleic acids, and microorganisms.

3,879 citations

01 Jun 2005

3,154 citations