Recent Patents on Nanotechnology - Volume 2, Issue 3, 2008

Nanofluidics is a relatively new area of research, generally viewed as the study of the behavior, manipulation, and control of fluids at nanometer (<100 nm) scales. At nanometer scales, fluids exhibit unique physical behaviors which are not present in larger structures. Nanofluidic structures have been successfully applied to technologies including analytical separations and the manipulation of proteins, RNA and DNA. There are increasing numbers of applications emerging, as well as innovative fabrication methods enabling the development of these applications. This review covers some of the recent and significant patents relating to nanofluidic devices and methods. We particularly focus on nanofluidic patents targeted to separate, sense and manipulate biofluids and the presence of macromolecules therein. Moreover, several important fabrication methods are reviewed relating to forming microscale and nanoscale fluidic structures. This study found that a majority of the current nanofluidic patents are intended for bioengineering and biotechnology applications, and none of these patents used gas as a working fluid. To date, the number of nanofluidic patents has been very limited, though it is expected that the nanofluidic area will grow in the near future.

Trace detection of chemicals and biological species like industrial gases, proteins, drug molecules, and chemical warfare agents, is an important issue to human health and safety. Central to this issue is the development of high sensitivity, high selectivity, high stability and rapid detection chemical and bio-sensors. With special geometry and chemical and physical properties, one-dimensional (1-D) metal oxide nanostructures have become the promising candidates for chemical and biosensing applications in recent years. Here, we intend to provide an overview on this interesting and important field. In the first part, the patents for rational synthesis of 1-D metal oxide nanostructures on a large scale will be introduced. The patents on chemical and biosensors built on 1-D metal oxide nanostructures are then introduced in the second part. Finally, we provide a review of the recent development of electronic nose systems using 1- D metal oxide nanostructures, which show great potential for the improvement of sensing abilities.

The simplicity of the electrospinning fabrication process, the diversity of electrospinnable materials, and the unique features associated with electrospun fibers make this technique and resultant structures attractive for various applications. The past few years witnessed the significant progresses in the application areas of electrospun fibers, which were demonstrated by the numbers of the recent published patents on electrospinning. It is very apparent that the current focus has been shifted from studying the modification of the electrospinning conditions and apparatus for obtaining fibers with different sizes, shapes, morphologies, structures, alignments before 2000 to looking for the possible applications of these resultant nanofibers with broad functionalities after 2001. The current paper presents a systematic review on the recent applications of electrospun nanofibers in a broad range of fields including biomedical applications such as drug delivery, tissue engineering, wound dressing and cosmetics, functional materials and devices such as composite reinforcement, filters, protective clothing and smart textiles, and energy and electronics such as batteries/cells and capacitors, sensors and catalysts. Although some of these applications may be still remained in the laboratory in the current stage, plenty of successful examples have proved that electrospun nanofibers have a bright future in a variety of industries.

Semiconductor photocatalysts with potential applications in splitting of water, degradation of toxic contaminant, and solar cells are very important research topics in recent years. In this short review, recent progresses of the synthesis and photocatalytic properties of highly functional nanostructured photocatalysts are briefly summarized. The patents for fabricating semiconductor photocatalysts are introduced in the first part. In the second part, the patents to improve photocatalytic activities of nano/microstructured photocatalysts from soft chemical method and other routes are introduced. Finally, current and future developments on highly functional photocatalysts are reviewed.

The data on nanoflower-like nanostructures are generalized for several groups of inorganic compounds (carbon, elemental metals, their alloys and compounds with the elements of V and VI Groups of the Periodic Table), as well as for a few coordination and organic compounds. Their synthetic techniques include oxidation of elemental metals, reduction of metal salts, thermal decomposition of relatively unstable compounds, or electrochemical route. Some current and possible applications of nanoflowers are noted.

Nanotechnology is one of the fastest developing new areas in science and technology. Ionizing radiation is widely applied for nanostructure synthesis and nanomaterials modification. The ability to fabricate structures with nanometric precision is of fundamental importance to any exploitation of nanotechnology. Nanofabrication involves various lithographies to write extremely small structures. An interesting field of radiation nanotechnological application concerns the development of nano-ordered hydrogels for biosensors. New trends and more precise treatment technology were applied: surface curing and modification, polymer functionalization are good examples of such developments. Patents on application of ionizing radiation in nanotechnology focused on many different approaches to this topic, not only nanoparticles synthesis but also nanostructure modification or functionalization.

Increasing need for portable nanoelectronic devices triggers the development of dimensionally small batteries. Nanobatteries are being designed for specific applications, including computer chips, micro-electromechanical systems (such as micro-actuators, micro-instruments, or micro-robots), or nanostructured medical devices. As the size of power source should be commensurate with the device it powers, battery miniaturization is an important design challenge faced by the battery community. Further advantages of such minute batteries include the long shelf life and a quick ramp up to full power. Hence, design may enable the nanobattery to stay dormant for several years, and then getting reactivated, so that it can provide immediately a burst of high energy.

The kinetics of thermal degradation process on thermoplastic polyurethanes (TPUs) adhesives with hydrophilic nanosilicas was studied using isothermal thermogravimetric analysis within the temperature range from 360 °C to 460 °C in nitrogen. The effect of nanosilicas with different hydrophilic degree in the thermoplastic polyurethanes was investigated. It was found that the thermoxidative degradation of polyurethane-silica nanocomposites takes place in one step. An analysis of the isothermal methods to evaluate kinetic parameters of decomposition of solids from isothermal thermogravimetric data is presented. Patents WO07146353A2 and US20070292623A1 have some relevant information about the topic develop in this study, because the principle in both cases relies on the interactions between reactive groups in the polymer (TPUs) and the silanol in the silica nano-particles.

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