Recent Patents on Nanotechnology - Volume 6, Issue 1, 2012

It is a great pleasure for us to address these words in the 5th anniversary of Recent Patents on Nanotechnology (NANOTEC) with which, we would like to congratulate to all the authors, reviewers, past and present Editorial Board Members, the Bentham people involved in the NANOTEC production, as well as readers, whom have made possible that NANOTEC was indexed and abstracted (ISI Web of Knowledge, Thomson Reuters) for the first time, reaching a 0.949 impact factor in 2010. Nanotechology is clearly interesting from the point of view of basic research but it also deals with the development of new materials, devices, or other systems in which the unique properties and behavior afforded by the nanometric scale open way to a world of wonders in which researchers and technologists need to shear experience for enlarging the current knowledge. In this way, NANOTEC intends to provide a platform for this purpose and brings out the opportunity to learn about nanotechnology in relation to their applications and their implications in the current and future society. Therefore, papers in these years have addressed issues not only related to the latest approaches applied for developing new materials with dimensions on the nanoscale but also to the use of nanotechnology in medicine, electronics, biomaterials, energy production and other fields of application. At the same time, it is also clear that nanotechnology, as any new technology, raises other concerns with special relevance in those related to toxicity and environmental impact of nanomaterials, and such issues have been also addressed in our Journal. We hope that in the next years the journal will continue increasing its impact and the readership. Finally, we would like to thank Bentham Science Publishers for appointing us as Chiefs of the Editorial Board of the journal, and also acknowledge the kind assistance of the entire Bentham team, and lately to Ms. Humera Sharif, who have helped us in these years in managing the journal.

Thermalization of photogenerated carriers in bulk materials is the main bottleneck for the conversion efficiency of conventional inorganic solar cells. Furthermore, the achieved conversion efficiency has nearly saturated during the last decade despite extensive research. Therefore, new device concepts to break through the efficiency barrier are highly requested. Nanotechnologies are the building blocks for next-generation solar cells because low-dimensional quantum structures can possibly reduce thermalization and extend the light absorption range. In addition, very thin nanostructured inorganic solar cells provide us with good opportunity to reach highly competitive mass production. Hereafter, recently invented inorganic solar cells using quantum structures will be reviewed.

Photovoltaics are amongst the most popular renewable energy sources and low-cost solar cell technologies are making progress to the market. Research on dye-sensitized solar cells (DSSCs) usually based on nanocrystalline TiO2 has been extensively pursued, and the number of papers and patents published in this area has grown exponentially over the last ten years. Research efforts have largely focused on the optimization of the dye, but recently the TiO2 nanocrystalline electrode itself has attracted more attention. It has been shown that particle size and shape, crystallinity, surface morphology and chemistry of the TiO2 material are key parameters to be controlled for optimized performance of the solar cell. This article will review the most recent research activities on nanostructured TiO2 for improvement of the DSSC performance.

This review attempts to visualize the actual impact of nanocellulose-based materials in different areas. A detailed search in recent patent databases on nanocellulose showed the importance of this material, as well as relevant topics concerning its technological preparations to obtain versatile new composites materials, and the applications of nanocellulose in different domains. At the present moment, the most common techniques for nanocellulose preparation were found to be acid and enzymatic procedures, oxidation, electrospinning, high pressure homogenization, and steam explosion processes. Concerning nanocellulose composites, several aspects were found in recent patents ranging from simple to complex structures with different properties. As unique materials, nanocellulose can be used in different areas of expertise, such as in biomedical and technical applications. This review is a useful tool for researchers to provide an update on nanocellulose patents in an expanding and interesting field of nanotechnology.

The aim of the article is to present a method for identifying trends in patent applications for nanotechnology applied to the health sector around the world, based on the International Patent Classification. This classification divides the sector into: dental care, drugs, diagnostic kits, and medical apparatus & medical care. The Derwent database was mined for patent documents using nanotechnology terms associated with the IPC subclasses from the health subsectors. The number of patents was found to be rising, led by the United States, particularly universities and R&D centers. In the dental care subsector, nanotechnology was found to be used in composite material for manufacturing dental appliances. In drugs, the focus is on the use of nanoparticulate compositions comprising agents that are useful for a variety of diseases. In diagnostic kits, nanostructures have been patented that are capable of detecting target analytes. Meanwhile, in medical apparatus & medical care, patent applications have been made for nanocapsules and/or nanocomposite materials inserted in devices and guide catheters. A study was also made of patents in Brazil, where the same assignees and the same country (United States) as in the survey of global patents were found to be the leading patent applicants / holders.

Ge nanowires exhibit wide application potential in the fields of nanoscale devices due to their excellently optical and electrical properties. This article reviews the recent progress and patents of Ge nanowires. The recent progress and patents for the synthesis of Ge nanowires using chemical vapor deposition, laser ablation, thermal evaporation, template method and supercritical fluid-liquid-solid method are demonstrated. Amorphous germanium oxide layer and defects existing in Ge nanowires result in poor Ohmic contact between Ge nanowires and electrodes. Therefore, Ge nanowires should be passivated in order to deposit connecting electrodes before applied in nanoelectronic devices. The experimental progress and patents on the application of Ge nanowires as field effect transistors, lithium batteries, photoresistors, memory cell and fluid sensors are discussed. Finally, the future development of Ge nanowires for the synthesis and practical application is also discussed.

Silver nanoparticles (AgNP; many other names such as nanosilver and colloidal silver) have already been used in everyday consumer products requiring broad spectrum antibiotic performance because of their enormous surface area and reactivity. Faunce and Watal [1] recently have critically analyzed the international regulatory issues for medical and domestic use in USA, EU, UK, and Australia. They found that in spite of the fact numerous studies have been made in the past decades, but many scientists are still uncertain of its safety. Very recently, Powers mentioned in her dissertation that her results showed positive that Ag+ and AgNP are developmental neurotoxicants in vitro and in vivo [2]. Therefore, there is a need to conduct a study to identify a global landscape of AgNPs and their products, and their manufacturers. A market- based intellectual property (IP) study has been conducted to examine the current global patent landscape of companies using AgNP in their consumer product development and production from 1980 to 2010. Detailed information in the compositions and formulations is extracted using a “two-stage” stage-gate process from the IP activity in the use of nanosilver. The first stage is in commercial products and the second stage is in consumer products. In the first stage for AgNP and AgNP-based commercial products, there were 7,422 patent families from January 1, 1980 to December 31, 2010. In the second stage for AgNP-based consumer products, 932 patent families from January 1, 1980 to December 31, 2010 were found. Korea, China and USA were found to be the major players in AgNP and AgNP-based commercial and consumer products. However, the recent patenting downturn was observed probably due to rising price in silver metal, regulatory uncertainty, public perception, and health safety & environmental (HS&E) issues.

We have reviewed the work on SOI slot optical waveguides followed by our work. In a slot waveguide structure, light can be confined in a low index slot guarded by high index slabs. Slot structures are being used in forming complex structures; such as ring resonator circuits. The increased round trip in ring resonator circuits signifies the importance of dispersion calculations. We did analytical and numerical investigations of slot structures' dispersion characteristics. Our dispersion tuned slot structures can help in reducing the dispersion effects on optical signal, which will in turn improve the efficiency of light-on-chip circuits. Since the advent of slot optical waveguides, SOI based slot optical waveguides have been under consideration. It has been found that glass based slot optical waveguide structures with relatively low refractive index contrast ratio can also play an important role in forming complex nano-size optical devices. We made use of power confined inside low index slot regions for a double slot structure. Opto-mechanical sensors have been proposed based upon: (a) variation in power confined inside low index slot region due to the movement of central high index slab under the action of external force (temperature, pressure, humidity, etc). vide Chinese Patent No. ZL 200710176770.1, 2007 (b) variation in power confined inside low refractive index slot regions due to movement of both slots under the action of external force (temperature, pressure, humidity, etc).

Full text available