Volume 2, Issue 3

The blood-brain barrier (BBB), which protects the central nervous system (CNS) from unnecessary substances, is a challenging obstacle in the treatment of CNS disease. Many therapeutic agents such as hydrophilic and macromolecular drugs cannot overcome the BBB. One promising solution is the employment of polymeric nanoparticles (NPs) such as poly (lactic-co-glycolic acid) (PLGA) NPs as drug carrier. Over the past few years, significant breakthroughs have been made in developing suitable PLGA and poly (lactic acid) (PLA) NPs for drug delivery across the BBB. Recent advances on PLGA/PLA NPs enhanced neural delivery of drugs are reviewed in this paper. Both in vitro and in vivo studies are included. In these papers, enhanced cellular uptake and therapeutic efficacy of drugs delivered with modified PLGA/PLA NPs compared with free drugs or drugs delivered by unmodified PLGA/PLA NPs were shown; no significant in vitro cytotoxicity was observed for PLGA/PLA NPs. Surface modification of PLGA/PLA NPs by coating with surfactants/polymers or covalently conjugating the NPs with targeting ligands has been confirmed to enhance drug delivery across the BBB. Most unmodified PLGA NPs showed low brain uptake (<1%), which indirectly confirms the safety of PLGA/PLA NPs used for other purposes than treating CNS diseases.

Metallic nanorods have a wide range of important technological applications. Fabrication of metallic nanorods of ~100 nm using physical vapor deposition (PVD) has been commonplace for several decades. On this length scale, nanorods have similar functionalities to bulk thin films with the advantage of increased surface area. When the lateral dimension is decreased to ~10 nm new functionalities emerge that are not present in thin film counterparts, such as catalysis. Small metallic nanorods, those ~10 nm, have classically been made through solution-based synthesis. Alternatively, recent advances in scientific understanding, a framework of nanorod growth, have opened the door to the fabrication of small nanorods through PVD. Growing small nanorods through PVD offers technologically relevant advantages over solution-based processing like direct control of aspect ratio, pure high-vacuum processing, and oriented attachment to a substrate. Among materials, gold (Au) has a wide range of technological applications and is a good prototype for understanding the behavior of common face center cubic metals. This article reviews solution processing and PVD of small metallic nanorods using Au as a prototype, in terms of scientific understanding and fabrication knowledge, and further compares and contrasts the two approaches.

Nanoparticle-based technologies have played important roles in providing opportunities for the development of a new generation of sensing tools. Because of their unique optical, chemical, electrical, and catalytic properties, gold nanoparticles (AuNPs) have been extensively studied for biological and chemical detections as well as analytical applications. AuNP-based sensors are expected to change the foundations of sensing and detecting biomolecules and metal ions. The ease of surface functionalization of AuNPs allows chemists to create the desired functionalities for specific applications. In this review, we will discuss the use of surface-functionalized AuNPs for fabricating smart sensors that are capable of detecting heavy metal ions, glucose, and specific biomolecules such as protein and DNA.

Cooling is one of the most important technique challenges faced by a range of diverse industries and military needs. There is an urgent need for the innovative heat transfer fluids with improved thermal properties over the currently available. This review paper discusses the concept of using phase-changeable nanoparticles to increase the effective heat capacity and the heat transfer rate of the fluid. A large amount of heat can be absorbed or released when these nanoparticles undergo phase transition from solid to liquid or liquid to gas or vice versa and, thus, enhancing the heat transfer rate. Two types of phase-change fluids are introduced: one contains liquid nanodroplets that will evaporate at elevated temperatures or solidifies at reduced temperatures, called “nanoemulsion fluids”; the other is suspensions of solid-liquid metallic phase-change nanoparticles. The material synthesis and property characterizations of these phase-changeable fluids are two main aspects of this paper. The explosive vaporization of the dispersed nanodroplets would significantly improve the heat transfer in the nanoemulsion fluid. The solid-liquid metallic phase-change nanoparticles will increase the effective heat capacity and thermal conductivity of the base fluids simultaneously. This paper also identifies the several critical issues in the phase-changeable fluids to be solved in the future.

Research on the nanomaterials containing one or more transition metals is growing tremendously, thanks to the large number of preparation processes available and to the novel applications that can be envisaged in several fields. This review presents an overview of the selected studies in the field of antimicrobial textiles, employing bioactive nanophases of elements/compounds such as silver, copper, or zinc oxide. In addition, the history of use of these antimicrobials and their mechanism of action are shortly reported. Finally, a short description is provided of the deposition/preparation methods, which are being used in the authors’ labs for the development of the textiles modified by the novel nanoantimicrobials.

The unique chemical and physical properties of the nano and microscale materials have led to important roles in the several scientific and technological fields. The magnetic nano/microparticles are of great interest because of its potential applications in, e.g., hyperthermia, magnetic resonance imaging (MRI), catalytic applications, etc. The decomposition of iron pentacarbonyl is one of the most common methods for the preparation of magnetic iron oxide and iron nanoparticles. However, Fe(CO) 5 is severely toxic and alternative precursors should be used. Here, we describe the recent advances in the synthesis and characterization of the elemental iron and iron oxide nano/microcomposite particles by the thermal decomposition of ferrocene. The described synthesis process is based on simple nontoxic approaches including, for example, a solventless process. The particle size and size distribution as well as their composition, crystallinity, shape, and magnetic properties can be controlled via the synthesis conditions.

A growing number of initiatives on nanotechnology research, education, and industry have been recently launched by several Arab countries to quickly build scientific capacity and track worldwide developments in nanotechnology. Some countries, namely, the oil-rich countries, have allocated large funds to support these initiatives, which are intended to serve the national interests in energy, water and food supply, medicine, and local industry. The other Arab countries are also pursuing nanotechnology, however, with fewer funds but with more human resources. This study assesses the current status of nanotechnology in the Arab Republic of Egypt, Hashemite Kingdom of Jordan, Kingdom of Morocco, Kingdom of Saudi Arabia, Republic of Tunisia, State of Kuwait, State of Qatar, Sultanate of Oman, and the United Arab Emirates (UAE). The study is aimed at having a top-level overview of the status of existing, underdevelopment, and planed educational and research programs relevant to nanotechnology. The overview also includes nanotechnology research focus areas, challenges, and opportunities.