Abstract
Nanotechnology is an emerging technology which is developing at an exponential rate. The technology utilizes novel characteristics of materials that are exhibited only at nanoscale level. Although still in early stages, this technology has signaled potential and breakthroughs in many areas such as medicine, computer technology, food industry, building construction, environment protection to mention just a few.
The many exciting products it promises have served to draw a lot of attention to it. Many findings of nanotechnology are quickly being implemented in viable commercial products. This is in spite of insufficient toxicological data about the environmental and biological effects of such nanomaterials.
As nanotechnology gains widespread application in various disciplines, it is imperative to understand its potential effects. This is important for its long terms sustainability. It is also equally critical to set up necessary control legislations and benchmark standards to control research and commercial application of this emerging technology.
The last half of the last century witnessed the technological world going “micro” evidenced by microdevices and microparticles. However, from the start of 21st century, the “micro” is poised to give way to the “Nano”. Nanotechnology is an emerging technology that is offering promises of breakthroughs cutting across multiple subjects such as medicine, food industry, energy sector and environmental remediation to mention a few.
The Potential of nanotechnology to solve hitherto “unsolvable” problems by conventional technologies has attracted the attention of government and commercial corporations with diverse interests. Billions of dollars for research and development continue to be channeled to nanotechnology projects all over the world. This paper presents the potential applications of nano-inventions in selected areas of medicine, pollution control, energy, construction, computer technology, and food sectors.
While the benefits of this emerging technology appear to be immense, its environmental and social effects also need to be given as much attention. Nanotechnology is a relatively nascent industry and its potential uses and effects need to be exhaustively established researched before mass production and commercialization. Nanotechnology is the most significant emerging technology today and will play a major role in social, economic, and environmental developments in this century.
What is nanotechnology?
Nanotechnology is the “creation of functional materials, devices, and systems through the manipulation of matter at a length of ~1-100 nm” (Srinivas, et al., 2010).
At such scale, matter exhibits new properties unlike those observed at larger scales (Wickson, Baun, & Grieger, 2010). This includes enhanced plasticity, change in thermal properties, enhanced reactivity and catalysis, negative refractivity, faster ion/electron transport and novel quantum mechanical properties (Vaddiraju, Tomazos, Burgess, Jain, & Papadimitrakopoulos, 2010).
The novel properties of matter at nanoscale has been explained by the presence of quantum effect, increase in surface area to volume ratio and alterations in atomic configurations (Wickson et al., 2010). The properties of nanomaterials may be characterized in terms of size, shape, crystallinity, light absorption and scattering, chemical composition, surface area, assembly structure, surface structure, as well as surface charge.
Some of the techniques used in nanoscience to study these properties include Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), Atomic Force Microscopy (ATM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), UV-Vis-nIR Spectroscopy, Extended X-ray Absorption Fine structure (EXAFS) , Photoluminescence Spectroscopy (XPS), Chemisorption among other new only developed ones.
The applications of nanotechnology are as a result of investigating and utilizing these properties (Wickson et al., 2010). There are a host of substances utilised in nanotechnology, the most researched ones are carbon, silicon dioxide and titanium dioxide (Robinson, 2010). Others are aluminum, zinc, silver, copper and gold (Robinson, 2010).
Nanotechnology projects continue to channel out a wide range of applications at a very high rate (Dang, Zhang, Fan, Chen, & C.Roco, 2010). This exponential growth rate is evident from the number of patent applications. Data by Dang and fellow researchers (2010) shows that patent application for nanotechnology inventions in developed countries increased from zero percent in 1991 to about 27 % in 2008 and that this growth is set to continue for the better part of this century.
Applications of nanotechnology
Spurred by huge funding from government and commercial players, nanotechnology projects continue to release more and more potential innovations into the market. This may be an indication that nanotechnology will in future play a pivotal role in scientific and economic development (Dang et al., 2010). Nanotechnology may be a critical solution for companies seeking to stay ahead of competitors. The potential of nanotechnology appears limitless as can be shown by the number of areas where it is already being applied.
Nanomedicine
This field encompasses pharmaceutical and medical nanotechnology. It is one of the most active areas of nanotechnology due it promises of novel therapeutic applications in crucial areas such as cancer therapy, drug delivery, imaging, biosensors and diagnosis.
Nanoparticles have been cited as having great potential in vivo imaging applications (Solomon & D’Souza, 2011). Already, a surface functionalized iron oxide nanoparticle is being used in modern imaging technologies such as magnetomotive imaging. This type of imaging is comparatively powerful and is expected to improve disease diagnosis significantly.
Nanoparticles are also being engineered to be used to enhance drug biodistribution and delivery to target sites in the body. This approach seeks to deliver drug agents to affected sites without damaging the healthy cells. This has been promising in the case of solid tumors whereby a transferrin-modified cyclodextrin nanoparticle successfully delivered anti-tumor agents to the target tumor site in human subjects (Solomon & D’Souza, 2011).
Nanoparticles have also displayed the ability to cross the blood-brain barrier, a major impediment to drug delivery to the brain, thus offering hope of improving the efficacy of some drugs. It has also been reported that nanoparticles conjugated to model antigens have been able to stimulate immunity in mice (Solomon & D’Souza, 2011). This indicates potential for application in improving vaccine therapy.
Elsewhere, nanoparticles have been used to engineer self-assembled tissue capable of repairing damaged tissues in rats though this is yet to be replicated in humans. Another area that has generated much interest is in production of microscopic and highly sensitive in vitro and in vivo biosensors. This application holds the promise of increasing portability and lowering the cost of such devices.
Nanoparticles are increasingly gaining application in cancer therapy. Nanoparticles are for this purpose is characterized by surface modifications that enable them interact with receptors of target cells. This makes it possible to develop therapies targeting cancerous cells only while leaving out healthy cells.
Free radical such as superoxide, hydroxides and peroxides has been known to produce disease initiating changes in cells. To counter this adverse effect, neuroprotective compound is being developed using carbon-60 fullerene (Silva, 2010). In terms of detection of biochemical compounds carbon nanotubes have been used for detection DNA and proteins in serum samples.
Nanotechnology has opened up new possibilities in regard to medical application. The technology has potential to alter medical therapy in many ways.
Pollution control
Waste disposal remains a challenging task for many industries. Current waste disposal technologies are expensive and require a lot of time to render the waste less harmful. In addition, current processes such as air stripping, carbon adsorption, biological reactors or chemical precipitation produce highly toxic wastes that require further disposal (Karn, Kuiken, & Otto, 2009).
Nanoremediation is a new form of waste disposal mechanism that utilizes nanoparticles to detoxify pollutants. nZVI, a nanoscale zero-valent iron has gained widespread use in this area and has been applied in remediating polluted in situ groundwater. This technology has been cited as cost-effective and faster compared to traditional pump-and-treat methods (Karn et al., 2009).
Other forms of pollution solutions employ the use of nanocatalysts. Just like biological and chemical catalysts, nanocatalysts speed up chemical reaction leading to decomposition of the reactive species. This is already being used to detoxify harmful vapor in cars and industrial machinery. Notable ongoing projects in pollution control include research on the recycling greenhouse gas emissions using carbon nanotubes (CNT) (Zhao, 2009).
For his effort, the researcher for this “green” solution received an $ 85,000 Foundation Research Excellence Award (Zhao, 2009). Nanoparticles have also been used to treat highly polluted industrial waste (Zhao, 2009). Nanotechnology is also aiding in improving current water purification technologies. The technology has made it possible to decrease the membrane pores to nanoscale levels leading to greater filtration power.
Energy applications
Nanotechnology has offered promises and potential for development of efficient and long-lasting energy devices. Nanofabricated energy storage compounds have been cited as potentially beneficial as they may serve as replacement for traditional environmentally harmful fossil fuels.
It is expected that nanoscience for energy application will transfer the nano-scale effects of energy carriers such as photons, phonons, electrons, and molecules to conventional photovoltaic, photochemical solar cells, thermoelectric, fuel cells and batteries. This is expected to greatly enhance the capacity, life, and efficiency of such energy producers. Laboratory tests have already shown that the nanomaterials-based electrodes enhance the charge storage capacity and reaction rates in fuel cells.
Also, nanomaterials such as carbon nanotubes and carbon nanohorns are proving useful in energy application due to their ability to provide excellent conductivity for charge transport (Yimin, 2011). Some nanomaterials e.g., PbTe-based quantum dot superlattice system, have demonstrated improved energy conversion efficiency. This property has been suggested to be replicated to produce more energy-efficient thermoelectric devices used to convert waste heat energy into electricity (Yimin, 2011).
This is necessary as the energy efficiency of most thermoelectric devices is very low. In terms of energy conservation, semiconductor nanostructures are actively being explored for the development of highly luminous and efficient light-emitting diodes (LED). This can have a significant impact in energy conservation as lighting uses about 20% of the total electric power generated (Yimin, 2011). Nanostructures are also gaining application in solar energy technologies.
Nonastructured photovoltaic materials have been cited as potentially significant in improving the efficiency of solar energy-based devices. To this end, nanomaterials, such as quantum dots and dye-sensitized semiconductors, are being tested for the possible production of next-generation solar devices projects (Yimin, 2011).
Nanotechnology has the potential to revolutionize man-made energy. Although still, in early phases, nanomaterials have the potential to deliver efficient, high capacity, clean and more durable energy solutions. The challenge, perhaps, remains the development of controlled large scale manufacturing approaches that will ensure greater realization of the powers of these promising materials.
Food nanotechnology
Application of nanoscience in food industry has opened up numerous new possibilities for the food sector. Areas that have gained prominence in this area include food packaging and preservation. Attention to this sector has been contributed by projections of enormous economic gains it offers. Data shows that sales of nanotechnology products to food and beverage packaging sector is expected to surpass US $20.4 billion beyond 2010 (Sozer & Kokini, 2008).
Already, bionanocomposites, which are nanostructures with enhanced mechanical, thermal, and porosity properties, are being used in food packaging. Additional benefits of bionanocomposites include being environmentally friendly as are they are biodegradable as well as increasing the food shelf life (Sozer & Kokini, 2008). Bioactive packaging materials made of nanomaterials have been used in controlling oxidation of foodstuffs and formation of undesirable textures and flavors (Sozer & Kokini, 2008).
One of the nanomaterials with high potential here is carbon nanotube. Apart from offering enhanced mechanical properties to food packaging materials, it has been discovered that the same tube could be possessing effective antimicrobial effects.
This is due to the fact that Escherichia coli bacteria have been found to immediately die upon coming in contact with aggregated nanotubes (Sekhon, 2010). Another area being explored is the fortification of food packaging with nano active additives that would allow controlled release of nutrient into the stored food.
Nanomaterials have also been said to have potential application in food preservation. Nanosensors made to fluoresce in different colors when in contact with food spoilage microorganisms, have been selected as a possible solution. This may reduce the time it takes to detect food spoilage and thus lessen cases of food poisoning.
Examples are nanosilica, already used in food packaging and nanoselenium, which has been added into some beverage and said to enhance uptake of selenium. Nano-iron is also available and is used as a health supplement, although it can also be used in the treatment of contaminated water. Said to be still under development, nanosalt has to be cited as having the benefit of enabling reduction in dietary salt intake.
Another nanoagent, nanoemulsion is already being used to add nanoemulfied bioctives and flavors to beverages (Sekhon, 2010). Nanoemulsions have also proved effective against gram-negative bacteria, a major food pathogen (Sekhon, 2010). Elsewhere scientists have also reported improved bioavailability and color changes brought about by iron/zinc-containing nanostructures.
Other areas being explored include probiotics and edible nanocoatings. Probiotics will entail using nanofabrications to deliver beneficial bacterial cells to the gut system while edible nanocoatings will be in the form of edible coatings to provide barrier to moisture, gas exchange, and deliver food enhancement additives.
It is clear that nanotechnology presents unlimited opportunities to the food industry. However, just like the controversy that followed GMOs food, foodstuffs bearing nano components are surely bound to generate a prolonged public debate. This is because the effects of such miniscule particles in the consumer body remain unclear. Nevertheless, given the nascent nature of nanotechnology, such opposition is expected.
Computer technology
Nanotechnology is expected to revolutionize computer architecture technologies. Current processors have an unofficial limit of 4 GHz. This year a synthetic material capable of replacing silicon, the long-standing semiconductor of choice in the 20th century, and attaining a clock speed of 6 GHz was unveiled (Partyka & Mazur, 2012).
This is because nanotechnology presents the possibility of adding even more transistors per a nanometric length than what is possible through current microprocessor development technologies.
What is even more interesting is that this development could not have come at a more opportune time as silicon processors are expected to have attained their maximum performance by 2020 (Partyka & Mazur, 2012). This year scientists have also announced the successful development of a Nano transistor “based on single molecules of a chemical compound” (Partyka & Mazur, 2012, n.p).
Application of nanotechnology in construction
Nanotechnology portends immense benefits for the future of the construction sector. From the amazing self-cleaning window to the “smog-eating” concrete, this technology has the capability of transforming building materials to new levels in terms of energy, light, strength, security, beauty and intelligence (Halicioglu, 2009).
The development of super-strength plastics has a possible application in diverse areas such as in cars, trucks, and planes where it can serve to replace heavy metals leading to significant energy savings (Zhao, 2009). Nanomaterials such as carbon nanotubes have been found to possess strength and flexibility on a much larger scale compared known strong materials such as steel. Nanocoatings have been suggested as possible solutions to insulation, microbial activity, and mildew growth in buildings (Halicioglu, 2009).
Nanotechnology is expected to produce unique bio-products characterized by hyper-performance and superior serviceability (Halicioglu, 2009).
Notable nanoparticles already in use in construction are titanium dioxide (TiO2) and carbon nanotubes (CNT’s). Titanium dioxide is being used in degrading pollutants in buildings while carbon nanotubes have been applied in strengthening and monitoring concrete (Halicioglu, 2009).
Just like other applications of nanotechnology, nanomaterials are used in construction sector yet their environmental, health effect, and other risks remain unclear. However, despite this drawback, nanotechnology has the potential to revolutionize building design and construction in the near future.
Concerns about nanotechnology
Concerns have been raised about nanotechnology. Nanoparticles have been said to be potentially unsafe for the biological system (Vishwakarma, Samal, & N.Manoharan, 2010). Owing to their small size, these particles can gain entry into the body easily through the skin, mucosal membranes of nose or lungs through inhalation. Their catalytic properties are likely to produce dangerous reactive radicals such as hyper-reactive oxygen with much toxic effects.
These reactive radicals have been linked to chronic diseases such as cancer. Once inside the body, nanoparticles may reach the brain or liver. This is because nanoparticles are able to cross the blood-brain barrier. Their effects on these organs are yet to be established. The nature of their toxicity remains a speculation, but the disruption in the body chemistry cannot be ignored.
The Royal Society of UK’s National Science Academy has reported that nanotube can cause lung fibrosis when inhaled in large amount over long periods (Vishwakarma et al., 2010). Early research has also shown that some types of nanoparticles could cause lung damage in rats (Vishwakarma et al., 2010).
Possible environmental effects of nanoparticles have also been documented. Because they are easily airborne, and adhesive, it is claimed nanoparticles may enter the food chain with profound undesirable changes on the ecosystem.
Currently, there are no standard techniques for assessing nanocompounds hazards. This, together with the unique features of nanomaterials – large surface area, multi forms, makes risk assessment difficult (Williams, Kulinowski, White, & Louis, 2010). Quality control for nanomaterials manufacturing, terminology as well as nomenclature standards are also lacking.
Additionally, it is alarming that currently there is no data on potential hazards, dose-response relationships and exposure levels of nanomaterials used in numerous applications (Musee, Brent, & Asthton, 2010). It is also worth stating that much of current funding on nanotechnology is directed toward potentially viable commercial projects while little is channeled towards risk assessment initiatives (Musee et al., 2010). This needs to be reversed.
Conclusion
Nanotechnology has the potential to revolutionize our lives. This is because it presents almost unlimited potential to make remarkable changes in virtually all fields ranging from medicine, computer technology, construction, environmental remediation, food industry, to new energy sources.
Despite presenting many potential benefits in many areas, nanotechnology of today is still in its infancy as just a few projects have been commercialized. Many are yet to undergo full lifecycle assessment. The number of nanotechnology innovations continues to rise. However, the same cannot be said of research about their potential effects on environment and biological systems.
As the world readily adapts to this new technology wave, concomitant effort should be directed to the understanding of their possible impacts. This is essential to ensure that nanomaterials do not become the new hazard of 21st century. The long-long term sustainability of this new technology may depend on the establishment of its risks.
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