http://www.mdpi.com/journal/nanomaterials Latest open access articles published in Nanomaterials at http://www.mdpi.com/journal/nanomaterials http://www.mdpi.com/2079-4991/2/2/134 Magnetic nanocrystals have been investigated extensively in the past several years for several potential applications, such as information technology, MRI contrast agents, and for drug conjugation and delivery. A specific property of interest in biomedicine is magnetic hyperthermia—an increase in temperature resulting from the thermal energy released by magnetic nanocrystals in an external alternating magnetic field. Iron oxide nanocrystals of various sizes and morphologies were synthesized and tested for specific losses (heating power) using frequencies of 111.1 kHz and 629.2 kHz, and corresponding magnetic field strengths of 9 and 25 mT. Polymorphous nanocrystals as well as spherical nanocrystals and nanowires in paramagnetic to ferromagnetic size range exhibited good heating power. A remarkable 30 °C temperature increase was observed in a nanowire sample at 111 kHz and magnetic field of 25 mT (19.6 kA/m), which is very close to the typical values of 100 kHz and 20 mT used in medical treatments. http://www.mdpi.com/2079-4991/2/2/134 Mon, 07 May 2012 00:00:00 CEST Nanomaterials 2012-05-07 2 2 Article 134 146 2079-4991 Iron Oxide Nanocrystals for Magnetic Hyperthermia Applications 2012-05-07 doi: 10.3390/nano2020134 Leisha M. Armijo Yekaterina I. Brandt Dimple Mathew Surabhi Yadav Salomon Maestas Antonio C. Rivera Nathaniel C. Cook Nathan J. Withers Gennady A. Smolyakov Natalie L. Adolphi Todd C. Monson Dale L. Huber Hugh D. C. Smyth Marek Osiński http://www.mdpi.com/2079-4991/2/2/113 A simple preparation of metal sulfide nanoparticles via the decomposition of thiobenzoate precursors at room temperature is presented and discussed. Long chain alkylamines were found to mediate the breakdown of metal thiobenzoates, such as those containing Ag, Cu, In and Cd, to produce uniform Ag2S, Cu2−xS, In2S3 and CdS nanoparticles respectively. The long chain amines are assumed to play dual roles as the nucleophilic reagent and the capping agent. It was found that sizes of the nanoparticles can be controlled by changing the type of amine used, as well as the molar ratio between amine and the precursor. We performed DFT calculations on a proposed mechanism involving an initial nucleophilic addition of amine molecule onto the thiocarboxylates. The proposed reaction was also confirmed through the analysis of by-products via infrared spectroscopy. On the basis of this understanding, we propose to manipulate the stability of the precursors by coordination with suitable stabilizing groups, such that the reaction kinetics can be modified to generate different nanostructures of interest. http://www.mdpi.com/2079-4991/2/2/113 Tue, 03 Apr 2012 00:00:00 CEST Nanomaterials 2012-04-03 2 2 Article 113 133 2079-4991 From Metal Thiobenzoates to Metal Sulfide Nanocrystals: An Experimental and Theoretical Investigation 2012-04-03 doi: 10.3390/nano2020113 Zhihua Zhang Wen Pei Lim Chiong Teck Wong Hairuo Xu Fenfang Yin Wee Shong Chin http://www.mdpi.com/2079-4991/2/2/92 Near-infrared (NIR) fluorescent probes offer advantages of high photon penetration, reduced light scattering and minimal autofluorescence from living tissues, rendering them valuable for noninvasive mapping of molecular events, assessment of therapeutic efficacy, and monitoring of disease progression in animal models. This review provides an overview of the recent development of the design and optical property of the different classes of NIR fluorescent nanoprobes associated with in vivo imaging applications. http://www.mdpi.com/2079-4991/2/2/92 Fri, 30 Mar 2012 00:00:00 CEST Nanomaterials 2012-03-30 2 2 Review 92 112 2079-4991 Near-Infrared Fluorescent Nanoprobes for in Vivo Optical Imaging 2012-03-30 doi: 10.3390/nano2020092 Chai-Hoon Quek Kam W. Leong http://www.mdpi.com/2079-4991/2/1/79 In order to study and develop an economical solution to environmental pollution in water, a wide variety of materials have been investigated. Natural zeolites emerge from that research as the best in class of this category. Zeolites are natural materials which are relatively abundant and non biodegradable, economical and serve to perform processes of environmental remediation. This paper contains a full description of a new method to characterize the superficial properties of natural zeolites of exotic provenience (Caribbean Islets) with atomic force microscopy (AFM). AFM works with the simplicity of the optical microscope and the high resolution typical of a transmission electron microscope (TEM). If the sample is conductive, structural information of mesoporous material is obtained using scanning and transmission electron microscopy (SEM and TEM), otherwise the sample has to be processed through the grafitation technique, but this procedure induces errors of topography. Therefore, the existing AFM method, to observe zeolite powders, is made in a liquid cell-head scanner. This work confirms that it is possible to use an ambient air-head scanner to obtain a new kind of microtopography. Once optimized, this new method will allow investigation of organic micelles, a very soft nanostructure of cetyltriammonium bromide (CTAB), upon an inorganic surface such as natural zeolites. The data also demonstrated some correlation between SEM microphotographies and AFM 3D images. http://www.mdpi.com/2079-4991/2/1/79 Mon, 05 Mar 2012 00:00:00 CET Nanomaterials 2012-03-05 2 1 Article 79 91 2079-4991 A New Method for Characterization of Natural Zeolites and Organic Nanostructure Using Atomic Force Microscopy 2012-03-05 doi: 10.3390/nano2010079 Domenico Fuoco http://www.mdpi.com/2079-4991/2/1/65 The wettability of reactively sputtered Y2O3, thermally oxidized Y-Y2O3 and Cd-CdO template assisted Y2O3 coatings has been studied. The wettability of as-deposited Y2O3 coatings was determined by contact angle measurements. The water contact angles for reactively sputtered, thermally oxidized and template assisted Y2O3 nanostructured coatings were 99°, 117° and 155°, respectively. The average surface roughness values of reactively sputtered, thermally oxidized and template assisted Y2O3 coatings were determined by using atomic force microscopy and the corresponding values were 3, 11 and 180 nm, respectively. The low contact angle of the sputter deposited Y2O3 and thermally oxidized Y-Y2O3 coatings is attributed to a densely packed nano-grain like microstructure without any void space, leading to low surface roughness. A water droplet on such surfaces is mostly in contact with a solid surface relative to a void space, leading to a hydrophobic surface (low contact angle). Surface roughness is a crucial factor for the fabrication of a superhydrophobic surface. For Y2O3 coatings, the surface roughness was improved by depositing a thin film of Y2O3 on the Cd-CdO template (average roughness = 178 nm), which resulted in a contact angle greater than 150°. The work of adhesion of water was very high for the reactively sputtered Y2O3 (54 mJ/m2) and thermally oxidized Y-Y2O3 coatings (43 mJ/m2) compared to the Cd-CdO template assisted Y2O3 coating (7 mJ/m2). http://www.mdpi.com/2079-4991/2/1/65 Wed, 29 Feb 2012 00:00:00 CET Nanomaterials 2012-02-29 2 1 Article 65 78 2079-4991 Wettability of Y2O3: A Relative Analysis of Thermally Oxidized, Reactively Sputtered and Template Assisted Nanostructured Coatings 2012-02-29 doi: 10.3390/nano2010065 Harish C. Barshilia Archana Chaudhary Praveen Kumar Natarajan T. Manikandanath http://www.mdpi.com/2079-4991/2/1/54 Near-monodispersed water soluble SnS nanoparticles in the diameter range of 3–6 nm are synthesized by a facile, solution based one-step approach using ethanolamine ligands. The optimal amount of triethanolamine is investigated. The effect of further heat treatment on the size of these SnS nanoparticles is discussed. Diffuse reflectance study of SnS nanoparticles agrees with predictions from quantum confinement model. http://www.mdpi.com/2079-4991/2/1/54 Mon, 16 Jan 2012 00:00:00 CET Nanomaterials 2012-01-16 2 1 Article 54 64 2079-4991 Synthesis and Size Dependent Reflectance Study of Water Soluble SnS Nanoparticles 2012-01-16 doi: 10.3390/nano2010054 Ying Xu Najeh Al-Salim Richard D. Tilley http://www.mdpi.com/2079-4991/2/1/31 New catalytic materials, based on palladium immobilized in ionic liquid supported on alginate, were elaborated. Alginate was associated with gelatin for the immobilization of ionic liquids (ILs) and the binding of palladium. These catalytic materials were designed in the form of highly porous monoliths (HPMs), in order to be used in a column reactor. The catalytic materials were tested for the hydrogenation of 4-nitroaniline (4-NA) in the presence of formic acid as hydrogen donor. The different parameters for the elaboration of the catalytic materials were studied and their impact analyzed in terms of microstructures, palladium sorption properties and catalytic performances. The characteristics of the biopolymer (proportion of β-D-mannuronic acid (M) and α-L-guluronic acid (G) in the biopolymer defined by the M/G ratio), the concentration of the porogen agent, and the type of coagulating agent significantly influenced catalytic performances. The freezing temperature had a significant impact on structural properties, but hardly affected the catalytic rate. Cellulose fibers were incorporated as mechanical strengthener into the catalytic materials, and allowed to enhance mechanical properties and catalytic efficiency but required increasing the amount of hydrogen donor for catalysis. http://www.mdpi.com/2079-4991/2/1/31 Wed, 11 Jan 2012 00:00:00 CET Nanomaterials 2012-01-11 2 1 Article 31 53 2079-4991 Study of Alginate-Supported Ionic Liquid and Pd Catalysts 2012-01-11 doi: 10.3390/nano2010031 Claire Jouannin Chloë Vincent Isabelle Dez Annie-Claude Gaumont Thierry Vincent Eric Guibal http://www.mdpi.com/2079-4991/2/1/15 Accurate determination of the intensity-average diameter of polystyrene latex (PS-latex) by dynamic light scattering (DLS) was carried out through extrapolation of both the concentration of PS-latex and the observed scattering angle. Intensity-average diameter and size distribution were reliably determined by asymmetric flow field flow fractionation (AFFFF) using multi-angle light scattering (MALS) with consideration of band broadening in AFFFF separation. The intensity-average diameter determined by DLS and AFFFF-MALS agreed well within the estimated uncertainties, although the size distribution of PS-latex determined by DLS was less reliable in comparison with that determined by AFFFF-MALS. http://www.mdpi.com/2079-4991/2/1/15 Thu, 05 Jan 2012 00:00:00 CET Nanomaterials 2012-01-05 2 1 Article 15 30 2079-4991 Accurate Size and Size-Distribution Determination of Polystyrene Latex Nanoparticles in Aqueous Medium Using Dynamic Light Scattering and Asymmetrical Flow Field Flow Fractionation with Multi-Angle Light Scattering 2012-01-05 doi: 10.3390/nano2010015 Haruhisa Kato Ayako Nakamura Kayori Takahashi Shinichi Kinugasa http://www.mdpi.com/2079-4991/2/1/1 Several mesoporous silica nanoparticle (MSN) contrast agents have been synthesized using a co-condensation method to incorporate two different Gd3+ complexes at very high loadings (15.5–28.8 wt %). These MSN contrast agents, with an MCM-41 type pore structure, were characterized using a variety of methods including SEM and TEM, nitrogen adsorption measurements, thermogravimetric analysis (TGA), direct current plasma (DCP) spectroscopy, and powder X-ray diffraction (PXRD). The magnetic resonance (MR) relaxivities of these contrast agents were determined using a 3 T MR scanner. The r1 relaxivities of these nanoparticles range from 4.1 to 8.4 mM−1s−1 on a per Gd basis. Additionally, the MSN particles were functionalized with an organic fluorophore and cancer cell targeting peptide to allow for demonstration of both the optical and MR contrast enhancing capabilities in vitro. http://www.mdpi.com/2079-4991/2/1/1 Tue, 27 Dec 2011 00:00:00 CET Nanomaterials 2011-12-27 2 1 Article 1 14 2079-4991 Mesoporous Silica Nanoparticles with Co-Condensed Gadolinium Chelates for Multimodal Imaging 2011-12-27 doi: 10.3390/nano2010001 Kathryn M. L. Taylor-Pashow Joseph Della Rocca Wenbin Lin http://www.mdpi.com/2079-4991/1/1/79 Quantum Dots (QDs) are promising alternatives to organic dyes as sensitisers for photocatalytic electrodes. This review article provides an overview of the current state of the art in this area. More specifically, different types of QDs with a special focus on heavy-metal free QDs and the methods for preparation and adsorption onto metal oxide electrodes (especially titania and zinc oxide) are discussed. Eventually, the key areas of necessary improvements are identified and assessed. http://www.mdpi.com/2079-4991/1/1/79 Tue, 15 Nov 2011 00:00:00 CET Nanomaterials 2011-11-15 1 1 Review 79 88 2079-4991 Quantum Dot Sensitized Photoelectrodes 2011-11-15 doi: 10.3390/nano1010079 Thomas J. Macdonald Thomas Nann http://www.mdpi.com/2079-4991/1/1/64 Plasmid DNA can be used as a template to yield gold, palladium, silver, and chromium nanoparticles of different sizes based on variations in incubation time at 70 °C with gold phosphine complexes, with the acetates of silver or palladium, or chromium acetylacetonate. The employment of mild synthetic conditions, minimal procedural steps, and aqueous solvents makes this method environmentally greener and ensures general feasibility. The use of plasmids exploits the capabilities of the biotechnology industry as a source of nanoreactor materials. http://www.mdpi.com/2079-4991/1/1/64 Fri, 21 Oct 2011 00:00:00 CEST Nanomaterials 2011-10-21 1 1 Article 64 78 2079-4991 Fabrication of Size-Tunable Metallic Nanoparticles Using Plasmid DNA as a Biomolecular Reactor 2011-10-21 doi: 10.3390/nano1010064 Jacopo Samson Irene Piscopo Alex Yampolski Patrick Nahirney Andrea Parpas Amit Aggarwal Raihan Saleh Charles Michael Drain http://www.mdpi.com/2079-4991/1/1/31 Metal nanoparticles are being extensively used in various biomedical applications due to their small size to volume ratio and extensive thermal stability. Gold nanoparticles (GNPs) are an obvious choice due to their amenability of synthesis and functionalization, less toxicity and ease of detection. The present review focuses on various methods of functionalization of GNPs and their applications in biomedical research. Functionalization facilitates targeted delivery of these nanoparticles to various cell types, bioimaging, gene delivery, drug delivery and other therapeutic and diagnostic applications. This review is an amalgamation of recent advances in the field of functionalization of gold nanoparticles and their potential applications in the field of medicine and biology. http://www.mdpi.com/2079-4991/1/1/31 Tue, 14 Jun 2011 00:00:00 CEST Nanomaterials 2011-06-14 1 1 Review 31 63 2079-4991 Functionalized Gold Nanoparticles and Their Biomedical Applications 2011-06-14 doi: 10.3390/nano1010031 Pooja M. Tiwari Komal Vig Vida A. Dennis Shree R. Singh http://www.mdpi.com/2079-4991/1/1/20 The fabrication and characterization of template silver nanoshell structures and the encapsulation of gold nanoparticles using biocompatible poly(oxyethylene)-poly(butylene) diblock co-polymer vesicles is described in this work. These vesicles have a narrow diameter size distribution around 200 nm. Silver nanoparticles (Ø = 1–10 nm) functionalized with decanethiol were successfully entrapped in the hydrophobic membrane and non-functionalized gold nanoparticles (Ø = 3.0–5.5 nm) were encapsulated in the vesicle core. Transmission Electron Microscopy confirms the localisation of the particles; silver functionalized nanoparticles appear to thicken the vesicle membrane as shown with TEM image analysis. The enhancement of the optical properties is confirmed using transmission spectrophotometry; the 430 nm plasmon resonance peak of the silver nanoparticles was replaced by a broader extinction spectrum to beyond 700 nm (O.D. = 0.8). For a number density of 4.8 x 1012 mL-1 the scattering cross section was calculated to be 0.92 x 10-4 μm2 with a scattering coefficient of 0.44 mm-1. The measurements indicate scattering cross section of 3.8 x 10-5 μm2, attenuation coefficient of 0.18 mm-1 and extinction efficiency equal to 1.2 x 10-3. Stable and biocompatible block co-polymer vesicles can potentially be used as plasmon-resonant optical contrast agents for biomedical applications. http://www.mdpi.com/2079-4991/1/1/20 Mon, 09 May 2011 00:00:00 CEST Nanomaterials 2011-05-09 1 1 Article 20 30 2079-4991 Metallic Nanoparticle Block Copoloymer Vesicles with Enhanced Optical Properties 2011-05-09 doi: 10.3390/nano1010020 Juan Leonardo Martinez-Hurtado http://www.mdpi.com/2079-4991/1/1/3 The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs) and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases. http://www.mdpi.com/2079-4991/1/1/3 Wed, 06 Apr 2011 00:00:00 CEST Nanomaterials 2011-04-06 1 1 Article 3 19 2079-4991 Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes 2011-04-06 doi: 10.3390/nano1010003 Thomas M. Higgins Holly Warren Marc in het Panhuis http://www.mdpi.com/2079-4991/1/1/1 It is my great pleasure to welcome you to Nanomaterials, a new open access journal, which is dedicated to the fabrication, characterization, functionalization, modeling and application of nanomaterials. In answer to the title question, I would like to (mis)quote one of my favourite pieces of literature: I "[We] hold these truths to be self-evident, that all men ... are endowed ... with certain unalienable rights, that among these are ..." free access to information and education. The prime goal of Nanomaterials is to publish first-class, original research articles under an open access policy with minimal fees for the authors. The quality of the published articles will be assured by a fast yet rigorous peer-review process. [...] http://www.mdpi.com/2079-4991/1/1/1 Thu, 04 Nov 2010 00:00:00 CET Nanomaterials 2010-11-04 1 1 Editorial 1 2 2079-4991 Another Journal on Nanomaterials? 2010-11-04 doi: 10.3390/nano1010001 Thomas Nann