Environmental Engineering Reference
In-Depth Information
31.2.2
nanoparticles as antimicrobials
Some nanoparticles such as silver, titanium dioxide, and zinc oxide are finding numerous applications as antimicrobials and
additives in consumer, health-related, and industrial products. Silver nanoparticles have a broad-spectrum antimicrobial activity
against several pathogens and are used as additives in health-related products such as bandages, catheters, and other materials
to prevent infection, especially in healing of wounds and burns. Nanoparticles of titanium dioxide are used in cosmetics, filters
that exhibit strong germicidal properties, and in conjunction with silver as an antimicrobial agent. moreover, due to its photo-
catalytic activity, it has been used in wastewater treatment. Zinc oxide (Zno) and copper oxide (cuo) nanomaterials are being
incorporated into a variety of medical and skin coatings due to their antimicrobial property. Zno nanoparticles are used in wall-
papers in hospitals as antimicrobials. Zno powder is an active ingredient for dermatological applications in creams, lotions, and
ointments on account of its antibacterial properties [5].
31.2.3
nanoparticles in textiles and coatings
Engineered nanoparticles can find good application in textile designing. They can be used to improve the quality of textiles used
by health and defence personnel as they have diverse properties such as self-cleaning; water- and dirt-repellent; antimicrobial, con-
ductive, and antistatic; solvent, uV, and abrasion resistance; and decreased gas permeability and flammability. For example,
carbon nanotubes have been used to improve electrical, antistatic, thermal-conductive, and flame-retardant properties of textile
composite fibers. metal and carbonaceous nanoparticles are usually used in the synthesis of nanotextiles. Nanoparticles of layered
silicate such as montmorillonite will find applications as carriers of agents and to improve the dyeing properties of fibers [6].
31.2.4
nanotechnologies in the food industry
in the food industry, nanoparticles such as micelles, liposomes, nanoemulsions, biopolymeric nanoparticles and cubosomes,
and nanosensors are finding increased application as they ensure long shelf life and safety of food. They are also known to
enhance the nutritive value and quality of food. For example, nanocapsules containing nutraceuticals are incorporated in
cooking oil, flavor enhancers are nanoencapsulated, and nanoparticles having the ability to selectively bind and remove chemi-
cals are used in foods. Nanoparticles have also been used for food packaging. Bionanocomposites are hybrid nanostructured
materials with improved mechanical, thermal, and gas barrier properties that are used in food packaging. Apart from protecting
food and increasing shelf life, these bionanocomposites are considered to be environmental-friendly as they minimize the use
of plastics as packaging materials [7].
31.3
toxicity of inorganic nanoparticlEs
metal oxide nanoparticles are often used as industrial catalysts and in therapeutics, and elevated levels of these particles have
been clearly demonstrated in the ecosystem. in recent years, there has been an increase in studies focusing on the toxicity of
nanoparticles (Table 31.1).
31.3.1
silver nanoparticles
Silver nanoparticles (Ag Nps) have been the most commercialized nanomaterial used in diverse applications. The antimicrobial
property of Ag Nps has led to their use in surgical and wound dressings and coatings in medical devices, but potential adverse
effects have also been reported in the literature. Although they are one of the most commercially viable nanotechnological prod-
ucts, safety issues have been raised regarding the use of such nanoparticles due to unintentional health and environmental
impacts. There are many studies focusing on the mechanisms by which Ag Np are toxic as their increasing application could lead
to their release into the environment and eventually result in environmental toxicity or ecotoxicity. To understand the effect of
exposure to Ag Np in human cells, a study was conducted to evaluate Ag Np-induced DNA damage, cell death, and functional
impairment in human mesenchymal stem cells (hmScs). cytotoxic effects were seen at a concentration of 10 μg/ml on exposing
Ag-Nps to hmScs for 1, 3 and 24 h. Transmission electron microscopy (TEm) studies revealed that AgNps were distributed to
the cytoplasm and nucleus. comet assay and chromosomal aberration test revealed that DNA damage occurred at a concentration
of 0.1 µg/ml. Therefore, AgNps could cause potential cyto- and genotoxic effects in hmScs [8]. in another study, the contribution
of silver ion to the toxicity of Ag Nps in A549 lung cells was investigated. cell viability measured by the for 3-(4,5-dimethythi-
azol-2-yl)-2,5-diphenyl tetrazolium bromide (mTT) assay revealed that Ag Np suspensions were more toxic when the initial
