hundred nanometers. Changing the size of quantum dots changes their optical
properties. Dendrimers are nanosized polymers built from branched units. The
surface of a dendrimer has numerous chain ends, which can be tailored to perform
specific chemical functions. This property could also be useful for catalysis. Also,
because three-dimensional dendrimers contain interior cavities into which other
molecules could be placed, they may be useful for drug delivery. Composites
combine the nanoparticles with other nanoparticles or with larger, bulk-type materials. Nanoparticles, such as nanosized clays, are already being added to products
ranging from auto parts to packaging materials, to enhance mechanical, thermal,
barrier, and flame-retardant properties.
Physicochemical Properties
The physicochemical properties of these nanomaterials are electrical, optical, catalytic, magnetic, mechanical, thermal, or imaging features that are highly desirable for
applications in commercial, medical, food science, food safety, military, and environmental sectors.
The main parameters of interest with respect to nanoparticle safety are:
1. Physical properties
(a) Size, shape, specific surface area, aspect ratio
(b) Agglomeration/aggregation state
(c) Size distribution
(d) Surface morphology/topography
(e) Structure, including crystallinity and defect structure
(f) Solubility
2. Chemical properties
(a) Structural formula/molecular structure
(b) Composition of nanomaterial (including degree of purity, known impurities
or additives)
(c) Phase identity
(d) Surface chemistry (composition, charge, tension, reactive sites, physical
structure, photocatalytic properties, zeta potential)
(e) Hydrophilicity/lipophilicity
The principal parameters of nanoparticles are their shape (including aspect ratios),
size, and the morphological substructure of the substance (Williams 2014).
Nanoparticles are presented as an aerosol (mostly solid or liquid phase in air), a
suspension (mostly solid in liquids) or an emulsion (two liquid phases) (Scientific
Committee on Emerging and Newly-Identified Health Risks (Sutariya and Pathak
2014; SCENIHR 2006). In the presence of chemical agents (surfactants), the surface
and interfacial properties may be modified. Indirectly such agents can stabilize
against coagulation or aggregation by conserving particle charge and by modifying
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H. V. Raghu et al.
properties. Dendrimers are nanosized polymers built from branched units. The
surface of a dendrimer has numerous chain ends, which can be tailored to perform
specific chemical functions. This property could also be useful for catalysis. Also,
because three-dimensional dendrimers contain interior cavities into which other
molecules could be placed, they may be useful for drug delivery. Composites
combine the nanoparticles with other nanoparticles or with larger, bulk-type materials. Nanoparticles, such as nanosized clays, are already being added to products
ranging from auto parts to packaging materials, to enhance mechanical, thermal,
barrier, and flame-retardant properties.
Physicochemical Properties
The physicochemical properties of these nanomaterials are electrical, optical, catalytic, magnetic, mechanical, thermal, or imaging features that are highly desirable for
applications in commercial, medical, food science, food safety, military, and environmental sectors.
The main parameters of interest with respect to nanoparticle safety are:
1. Physical properties
(a) Size, shape, specific surface area, aspect ratio
(b) Agglomeration/aggregation state
(c) Size distribution
(d) Surface morphology/topography
(e) Structure, including crystallinity and defect structure
(f) Solubility
2. Chemical properties
(a) Structural formula/molecular structure
(b) Composition of nanomaterial (including degree of purity, known impurities
or additives)
(c) Phase identity
(d) Surface chemistry (composition, charge, tension, reactive sites, physical
structure, photocatalytic properties, zeta potential)
(e) Hydrophilicity/lipophilicity
The principal parameters of nanoparticles are their shape (including aspect ratios),
size, and the morphological substructure of the substance (Williams 2014).
Nanoparticles are presented as an aerosol (mostly solid or liquid phase in air), a
suspension (mostly solid in liquids) or an emulsion (two liquid phases) (Scientific
Committee on Emerging and Newly-Identified Health Risks (Sutariya and Pathak
2014; SCENIHR 2006). In the presence of chemical agents (surfactants), the surface
and interfacial properties may be modified. Indirectly such agents can stabilize
against coagulation or aggregation by conserving particle charge and by modifying
104
H. V. Raghu et al.