The publication of patent applications by the U.S. Patent and Trademark Office (USPTO) provides a means of following new developments in a field of interest. One such field of interest is nanotechnology, and reviewing some of the published applications in this field gives some insight into opportunities for further exploration and future patent protection.
The number of issued patents involving nanotechnology has increased by more than 600% in the last five years, from 370 in 1997 to 2,650 in 2002. While only 2% of all patents issued in 2002 involved nanotechnology, that was much higher than the 0.3% in 1997. About 90% of the applications came from private corporations, while universities filed roughly 7%, and about 3% were filed by government agencies and collaborative research centers. Nanotechnology-related patent applications are evenly split between process and product inventions. Most of the inventions are refinements to known technology, but a significant number can be considered "revolutionary" or pioneering in nature. The rest of this article shows the diversity of chemical engineering applications using nanotechnology.
The extremely high surface area of nanoparticles has been known to raise reaction rate coefficients and ultimately reduce the energy requirements for a reactor. According to patent application no. 2002/0100578, nanoparticles are also useful in heat-transfer fluids, where the particles' high surface area raises the convective heat-transfer coefficients and heat capacities of the fluids and increases collision-induced motion, all of which result in significant energy and cost savings for heat-transfer systems.
Nanoparticle-containing fibers can be improved by forming them from nanoparticles that are surface-derivatized with functional groups that allow the nanoparticles themselves to link together in a "polymerization" reaction (2003/0083401). The fiber is said to benefit from reduced agglomeration of the particles and greater control of their size, both of which enhance product uniformity.
Drug delivery has benefited from nanotechnology. Orally administered nanowires (termed "nanorobots") deliver antibodies to specific cells and probe and manipulate bio-molecules at the cellular and subcellular levels. Nanowires can be made to act as antibodies themselves by attaching at one end a ligand to bind to a specific target molecule and at the other end a ligand that attracts immune cells (2002/0187504). With the assistance of a surface stabilizer, insulin is formed into nanoparticles, which provide a rapid onset of insulin activity and prolonged activity (2003/0095928). Nanotechnology is also used to deliver Taxol, antigens and antibiotics such as penicillin.
Nanoparticles have also been used to provide the controlled release of fragrances, biocides and antifungals on textiles. For instance, "textile-reactive" nanoparticles can be made to bind to the textile fiber through a covalent bond (2003/0013369).
Nanoscale polymers can increase the stability and consistency of hair- and skin-care preparations. Polymers with a diameter of 10-500 ran provide increased dermatological compatibility and improved sensory properties due to their high compatibility with keratin (2003/0086894,2003/0059385 and 2003/0003070).
In coatings, nanoparticle hardcoats have been applied to the surfaces of glass, quartz, wood and metal, as well as thermoset and thermoplastic materials such as acrylics and polycarbon ates, providing protection of the sub-strate. Smudge resistance can be increased by using nanoparticles with exposed reactive groups that covalently attach to smudge-resistant components (2003/0068486).
The incorporation of nanoparticles into composite materials imparts novel properties to macro-sized materials without altering other, favorable properties. For example, embedding silver nanoparticles makes glass photochromic (i.e., capable of light-induced, reversible darkening); the nanoparticles are incorporated into the glass at room temperature without the need for processing at higher temperatures (2003/0099834).
The use of nanoparticles in separation technology has seen numerous improvements as well. For example, superparamagnetic nanoparticles are placed in contact with a liquid or gaseous medium to bind to specified targets in the medium; a magnetic field then separates the target-laden nanoparticles from the medium (2003/0038083). The advantage of nanoparticles is that they do not retain magnetism after the field is removed, since retained magnetism causes the laden nanoparticles to aggregate, which inhibits separation.
The qualities that make any invention patentable are novelty, nonobviousness, and utility. While many unique properties of nanotechnology are already known, more are being discovered, as are new ways of exploiting known properties, all of which can lead to patentable inventions. The growth of patents in nanotechnology is a clear indication of the potential of this field.