History And Future Of Nanotechnology

History of nanotechnology

Human dreams and imagination often give rise to new science and technology. Nanotechnology, a 21st-century frontier, was born out of such dreams. Nanotechnology is defined as the understanding and control of matter at dimensions between 1 and 100 nm where unique phenomena enable novel application Although human exposure to nanoparticles has occurred throughout human history, it dramatically increased during the industrial revolution. The study of nanoparticles is not new. The concept of a “nanometer” was first proposed by Richard Zsigmondy, the 1925 Nobel Prize Laureate in chemistry. He coined the term nanometer explicitly for characterizing particle size and he was the first to measure the size of particles such as gold colloids using a microscope.

Modern nanotechnology was the brain child of Richard Feynman, the 1965 Nobel Prize Laureate in physics. During the 1959 American Physical Society meeting at Caltech, he presented a lecture titled, “There’s Plenty of Room at the Bottom”, in which he introduced the concept of manipulating matter at the atomic level. This novel idea demonstrated new ways of thinking and Feynman’s hypotheses have since been proven correct. It is for these reasons that he is considered the father of modern nanotechnology.

Almost 15 years after Feynman’s lecture, a Japanese scientist, Norio Taniguchi, was the first to use “nanotechnology” to describe semiconductor processes that occurred on the order of a nanometer. He advocated that nanotechnology consisted of the processing, separation, consolidation, and deformation of materials by one atom or one molecule. The golden era of nanotechnology began in the 1980s when Kroto, Smalley, and Curl discovered fullerenes and Eric Drexler of Massachusetts Institute of Technology (MIT) used ideas from Feynman’s “There is Plenty of Room at the Bottom” and Taniguchi’s term nanotechnology in his 1986 book titled, “Engines of Creation: The Coming Era of Nanotechnology.” Drexler proposed the idea of a nanoscale “assembler” which would be able to build a copy of itself and of other items of arbitrary complexity. Drexler’s vision of nanotechnology is often called “molecular nanotechnology.” The science of nanotechnology was advanced further when Iijima,2 another Japanese scientist, developed carbon nanotubes.

The beginning of the 21st century saw an increased interest in the emerging fields of nanoscience and nanotechnology. In the United States, Feynman’s stature and his concept of manipulation of matter at the atomic level played an important role in shaping national science priorities. President Bill Clinton advocated for funding of research in this emerging technology during a speech at Caltech on January 21, 2000. Three years later, President George W. Bush signed into law the 21st Century Nanotechnology Research and Development Act. The legislation made nanotechnology research a national priority and created the National Technology Initiative (NNI). Today, the NNI is managed within a framework at the top of which is the President’s Cabinet-level National Science and Technology Council (NSTC)and its Committee on Technology. The Committee’s Subcommittee on Nanoscale Science, Engineering, and Technology (NSET) is responsible for planning, budgeting, implementation, and review of the NNI and is comprised of representatives from 20 US departments and independent agencies and commissions

Future of nanotechnology

In a timeframe of approximately half a century, nanotechnology has become the foundation for remarkable industrial applications and exponential growth. For example, in the pharmaceutical communities of practice, nanotechnology has had a profound impact on medical devices such as diagnostic biosensors, drug delivery systems, and imaging probes. In the food and cosmetics industries, use of nanomaterials has increased dramatically for improvements in production, packaging, shelf life, and bioavailability. Zinc oxide quantum dot nanoparticles show antimicrobial activity against food-borne bacteria, and nanoparticles are now used as food sensors for detecting the food quality and safety. The most recent goals and accomplishments of each of the US federal entities listed on  are summarized in the NSTC’s report titled, “Supplement to the President’s Budget for Fiscal Year 2015—The National Nanotechnology Initiative.”

Today, nanotechnology impacts human life every day. The potential benefits are many and diverse. However, because of extensive human exposure to nanoparticles, there is a significant concern about the potential health and environmental risks. These concerns led to the emergence of additional scientific disciplines including nanotoxicology and nanomedicine. Nanotoxicology is the study of potential adverse health effects of nanoparticles. Nanomedicine, which includes subsectors such as tissue engineering, biomaterials, biosensors, and bioimaging, was developed to study the benefits and risks of nanomaterials used in medicine and medical devices. Some of the potential benefits of medical nanomaterials include improved drug delivery, antibacterial coatings of medical devices, reduced inflammation, better surgical tissue healing, and detection of circulating cancer cells. However, due to lack of reliable toxicity data, the potential to affect human health continues to be a major concern.

Safety evaluation of nanomaterials

Safety of consumer products containing nanomaterials was an early societal concern. When US regulatory agencies adopted the NNI definition of the nanomaterials, it was expected that the risk assessment techniques used for drugs and toxic chemicals would be used for the risk evaluation of nanomaterials. However, reports of large data gaps indicated the need to augment conventional toxicity testing methods. Walker and Bucher summarized four reasons why nanomaterials need to be assessed differently than through the conventional methods: (a) new routes of exposure emerge when a nanomaterial is small enough to enter new cellular portals; (b) Surface properties impact dosimetry because they alter the toxicokinetics of materials of similar size and shape; (c) The new commercial applications might lead to new biological interactions and unforeseen toxicities; and (d) Assessment of relative risk using dose expressed in terms of mass may lead to false outcomes because some nanomaterials’ dose can scale with a size-dependent property such as surface area. Because physical properties of nanomaterials are relevant to the first three steps in the US risk assessment/management paradigm, namely hazard identification, dose–response assessment, and exposure assessment, they are relevant to the fourth step, risk characterization. Since much of the needed physical characteristics information (e.g. shape, composition, surface area, surface properties, and agglomeration state) is unavailable, the need for reliable and reproducible exposure and toxicity data persists. Although significant progress in research in nanotoxicology and nanomedicine has been made in recent years, much more work remains to be done.

The challenges are not the United States’ alone. Unfortunately, there is no internationally accepted standard protocol for toxicity testing of nanomaterials. Furthermore, there are few if any internationally accepted well-characterized–positive controls available at the present time for nanomaterial studies. The current practice is for investigators to use their own protocols and compare the results with the vehicle control. Under such circumstances, it is difficult to compare published nanotoxicity results. In this context, internationally approved models and methods are needed to enable regulatory agencies to evaluate the safety of nanomaterials. Efforts are ongoing and methods for safety evaluation of nanomaterials have been developed. Standardized methods have also been suggested for this purpose. Availability of reference materials for nanotoxicity testing has been initiated by the UK Nanotechnology Research Coordination Group and the US National Nanotechnology Characterization Laboratory. The International Alliance for Nano Environment, Human Health and Safety Harmonization has started developing test protocols for nanotoxicity testing. In the light of the toxicity testing in the 21st century proposed by the US National Research Council (NRC),high-throughput screening of nanomaterials seems promising and may be possible in the not too distant future. Although the complex nature of the nanomaterials makes the development of their safety assessment challenging, the future of the nanotechnology appears to be bright.

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