Applications of Nanotechnology
With nanotechnology, a large set of materials with distinct properties (optical, electrical, or magnetic) can be fabricated.
Nanotechnologically improved products rely on a change in the physical properties when the feature sizes are shrunk. Nanoparticles
for example take advantage of their dramatically increased surface area to volume ratio. Their optical properties, e.g. fluorescence, become a function of the particle diameter. When brought into a bulk material, nanoparticles can strongly influence the
mechanical properties, such as the stiffness or elasticity. Example, traditional polymers can be reinforced by nanoparticles resulting in novel materials e.g. as lightweight replacements for metals. Therefore, an
increasing societal benefit of such nanoparticles can be expected.
Such nanotechnologically enhanced materials will enable a weight reduction accompanied by an increase in stability and
an improved functionality.
Medicine
The biological and medical research communities have exploited the unique properties of nanomaterials for various applications
(e.g., contrast agents for cell imaging and therapeutics for treating cancer). Terms such as biomedical nanotechnology, bionanotechnology,
and nanomedicine are used to describe this hybrid field.
Functionalities can be added to nanomaterials by interfacing them with biological molecules or structures. The size of
nanomaterials is similar to that of most biological molecules and structures; therefore, nanomaterials can be useful for both
in vivo and in vitro biomedical research and applications.
Thus far, the integration of nanomaterials with biology has led to the development of diagnostic devices, contrast agents,
analytical tools, physical therapy applications, and drug-delivery vehicles.
Diagnostics
Nanotechnology-on-a-chip is one more dimension of lab-on-a-chip technology. Biological tests measuring the presence or activity of selected substances become quicker, more sensitive and
more flexible when certain nanoscale particles are put to work as tags or labels. Magnetic nanoparticles, bound to a suitable
antibody, are used to label specific molecules, structures or microorganisms. Gold nanoparticles tagged with short segments
of DNA can be used for detection of genetic sequence in a sample. Multicolor optical coding for biological assays has been achieved
by embedding different-sized quantum dots into polymeric microbeads. Nanopore technology for analysis of nucleic acids converts strings of nucleotides directly into
electronic signatures.
Drug delivery
The overall drug consumption and side-effects can be lowered significantly by depositing the active agent in the morbid
region only and in no higher dose than needed. This highly selective approach reduces costs and human suffering. An example
can be found in dendrimers and nanoporous materials. They could hold small drug molecules transporting them to the desired location. Another vision
is based on small electromechanical systems: NEMS are being investigated for the active release of drugs. Some potentially important applications include cancer treatment
with iron nanoparticles or gold shells.
A targeted or personalized medicine reduces the drug consumption and treatment expenses resulting in an overall societal
benefit by reducing the costs to the public health system.
Tissue engineering
Nanotechnology can help to reproduce or to repair damaged tissue. This so called “tissue engineering” makes
use of artificially stimulated cell proliferation by using suitable nanomaterial-based scaffolds and growth factors. Tissue
engineering might replace today’s conventional treatments, e.g. transplantation of organs or artificial implants. On
the other hand, tissue engineering is closely related to the ethical debate on human stem cells and its ethical implications.
Chemistry and environment
Chemical catalysis and filtration techniques are two prominent examples where nanotechnology already plays a role. The
synthesis provides novel materials with tailored features and chemical properties e.g. nanoparticles with a distinct chemical
surrounding (ligands) or specific optical properties. In this sense, chemistry is indeed a basic nanoscience. In a short-term
perspective, chemistry will provide novel “nanomaterials” and in the long run, superior processes such as “self-assembly”
will enable energy and time preserving strategies.
In a sense, all chemical synthesis can be understood in terms of nanotechnology, because of its ability to manufacture
certain molecules. Thus, chemistry forms a base for nanotechnology providing tailor-made molecules, polymers etc. and furthermore
clusters and nanoparticles.
Catalysis
Chemical catalysis benefits especially from nanoparticles, due to the extremely large surface to volume ratio. The application potential of
nanoparticles in catalysis ranges from fuel cell to catalytic converters and photocatalytic devices. Catalysis is also important
for the production of chemicals.
Filtration
A strong influence of nanochemistry on waste-water treatment, air purification and energy storage devices is to be expected.
Mechanical or chemical methods can be used for effective filtration techniques. One class of filtration techniques is based
on the use of membranes with suitable hole sizes, whereby the liquid is pressed through the membrane. Nanoporous membranes
are suitable for a mechanical filtration with extremely small pores smaller than 10 nm (“nanofiltration”). Nanofiltration
is mainly used for the removal of ions or the separation of different fluids. On a larger scale, the membrane filtration technique
is named ultrafiltration, which works down to between 10 and 100 nm. One important field of application for ultrafiltration is medical purposes as can be found in renal dialysis.
Magnetic nanoparticles offer an effective and reliable method to remove heavy metal contaminants from waste water by making
use of magnetic separation techniques. Using nanoscale particles increases the efficiency to absorb the contaminants and is
comparatively inexpensive compared to traditional precipitation and filtration methods.
Energy
The most advanced nanotechnology projects related to energy are: storage, conversion, manufacturing improvements by reducing
materials and process rates, energy saving e.g. by better thermal insulation, and enhanced renewable energy sources.
Reduction of energy consumption
A reduction of energy consumption can be reached by better insulation systems, by the use of more efficient lighting or
combustion systems, and by use of lighter and stronger materials in the transportation sector. Currently used light bulbs
only convert approximately 5% of the electrical energy into light. Nanotechnological approaches like light-emitting diodes (LEDs) or quantum caged atoms (QCAs) could lead to a strong reduction of energy consumption for illumination.
Increasing the efficiency of energy production
Today's best solar cells have layers of two different semiconductors stacked together to absorb light at different energies but they still only manage to use 30 percent of the Sun's energy.
Commercially available solar cells have much lower efficiencies (less than 20%). Nanotechnology could help increase the efficiency
of light conversion by specifically designed nanostructures. The degree of efficiency of combustion engines is not higher
than 15-20% at the moment. Nanotechnology could improve combustion by designing specific catalysts with maximized surface
area. Scientists have recently developed tetrad-shaped nanoparticles that, when applied to a surface, instantly transform
it into a solar collector.[citation needed]
The use of more environmentally friendly energy systems
An example for an environmentally friendly form of energy is the use of fuel cells powered by hydrogen, which is ideally produced by renewable energies. Probably the most prominent nanostructured material
in fuel cells is the catalyst consisting of carbon supported noble metal particles with diameters of 1- 5 nm. Suitable materials
for hydrogen storage contain a large number of small nanosized pores. Therefore many nanostructured materials like nanotubes,
zeolites or alanates are under investigation.
Nanotechnology can contribute to the further reduction of combustion engine pollutants by nanoporous filters, which can
clean the exhaust mechanically, by catalytic converters based on nanoscale noble metal particles or by catalytic coatings
on cylinder walls and catalytic nanoparticles as additive for fuels.
Recycling of batteries
Because of the relatively low energy density of batteries the operating time is limited and a replacement or recharging
is needed. The huge number of spent batteries and accumulators represent a disposal problem. The use of batteries with higher
energy content or the use of rechargeable batteries or supercapacitors with higher rate of recharging using nanomaterials could be helpful for the battery disposal problem.
Information and communication
Current high-technology production processes are based on traditional top down strategies, where nanotechnology has already
been introduced silently. The critical length scale of integrated circuits is already at the nanoscale (50 nm and below) regarding the gate length of transistors in CPUs or DRAM devices.
