Biomedical Engineering Reference
In-Depth Information
wastewater. The electricity-producing bacteria are kept separate from the electron acceptor by a
proton exchange membrane, allowing the electrons to pass from the bacteria to the anode. The elec-
trons are then combined with protons from oxygen to yield water.
NMs have been utilized in the improvement of MFCs to enhance surface areas, chemical stabili-
ties, and biocompatibilities. For example, nanowires are thought to have a potential in facilitating
the transfer of electrons from the organism to the electrode (Logan et al. 2006, Reguera et al. 2005).
1.4.4 a pplIcatIoNs IN c oMMoNly u sed p roducts
1.4.4.1 Cosmetics
It is well established that a prolonged exposure to UV light causes damage to the skin in the form
of burns and an increased risk of cancer. Sunscreens and cosmetic preparations aim to decrease the
risk of cancer by offering protection from sun rays. Nanosized titanium dioxide (TiO 2 ) and zinc
oxide (ZnO) are often used in such preparations to block UV exposure without penetrating the skin
and causing dermal discomfort (Nohynek et al. 2007, Nohynek et al. 2008, Schilling et al. 2010).
Sunscreens containing TiO 2 and ZnO NPs have been deemed to be some of the safest sunscreen
products in the market.
1.4.4.2 Coatings
NMs have been used for extremely thin coatings for decades, if not centuries. Today, thin coatings
are used in a wide range of applications, including microelectronics, optoelectronic devices, archi-
tectural glass, anticounterfeit devices, and catalytically active surfaces. Structured coatings with
nanosized-scale characteristics in more than one dimension assure to be a significant foundational
technology for the future.
1.4.4.3 Self-Cleaning Windows
Self-cleaning windows, coated in extremely hydrophobic TiO 2 , have been shown to be rather nor-
mal. The TiO 2 NPs speed up the breakdown of dirt and bacteria in the presence of water and sun-
light, allowing them to be washed off the glass without any difficulty.
1.4.4.4 Scratch-Resistant Materials
Intermediate, nanosized layers, linking the hard outer layer and the substrate material, considerably
improve wear- and scratch-resistant coatings. The intermediate layers are constructed to give a good
bonding and graded matching of mechanical and thermal properties, leading to the improvement
of adhesion properties.
1.4.4.5 Textiles
NPs have well-established applications in coating textiles, such as nylon, to provide antimicrobial
qualities. In addition, adjustments in the porosity at a nanosized scale and surface roughness in dif-
ferent polymers and inorganic materials allow for the production of ultrahydrophobic, waterproof,
and stain-resistant fabrics.
1.4.4.6 Insulation Materials
Nanocrystalline materials produced by the sol-gel method provide a foam-like structure, known as an
“aerogel” (Hrubesh and Poco 1995). Aerogels are made of continuous, three-dimensional networks of
particles and voids. Aerogels are porous, enormously lightweight, and have low thermal conductivity.
1.4.4.7 Nanocomposites
Materials that are made up of a combination of two or more components are known as compos-
ites. They are constructed to demonstrate the overall, best characteristics of each component, such
as mechanical, biological, optical, electric, or magnetic qualities. Nanocomposites, consisting of
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