Biomedical Engineering Reference
In-Depth Information
The definition of “nanoscale” encompasses the size ranging from approximately 1 nm to
100 nm. The “approximately” is assumed to be applicable for both the lower and upper
limits of the definition, and size can refer to all three dimensions [19]. The “nano-object”
is defined as a material with one, two, or three external dimensions in the nanoscale. The
term “nanostructure” refers to a composition of interrelated constituent parts, in which
one or more of those parts is/are a nanoscale region. The “nanostructured material” is
defined as a material having an internal or surface nanostructure. This definition sug-
gests that the dimensions of a nanostructured material can be larger than 100 nm; there
exists overlapping between nano-objects and nanostructured materials: nano-objects can
be nanostructured. The “nanoscale property” refers to a characteristic of a nano-object or
nanoscale region. The “nanoscale phenomenon” refers to an effect attributable to nano-
objects or nanoscale regions. The “nanomaterial” refers to a material with any external
dimensions in the nanoscale or having an internal structure or surface structure in the
nanoscale. Thus, the nanomaterial is defined as the sum of nano-objects and nanostruc-
tured materials. The “manufactured nanomaterial” refers to a NM intentionally produced
for commercial purposes to have specific properties or a specific composition. And lastly,
the “engineered nanomaterial” refers to a NM designed for a specific purpose or function.
Lovestam et al. [19] have a suggestion on the definition of “nanomaterials.” However, we
believe that it is more important to clearly define the term “nanoscale,” because all other
definitions related to NMs are based upon this. The current definition of “nanoscale” in
the ISO/TS 80004-1:2010 document does not make the term “size” clear. As associated
to a material, we suggest that the “size” is the size of an original, individual material, or a
named “primary” material, for example, a particle, wire, or tube, rather than an agglomer-
ate and aggregate.
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ISO/TS 27687:2008 Nanotechnologies—Terminology and definitions for some types of
nano-objects, i.e. nanoparticle, nanoplate, nanofiber, nanotube, nanorod, nanowire, and
quantum dot. This document is revised as ISO/TS 80004-2. “Nanoparticle” is defined
as a nano-object with all three external dimensions in the nanoscale. The “nanoplate”
is defined as a nano-object with one external dimension in the nanoscale and the two
other, significantly larger, external dimensions. There is no definition of “nanosheet” in
the ISO-related document at this time. The size range of the “nanosheet” may be differ-
ent from that of the “nanoplate.” With regard to the thickness of graphene (0.334 nm), we
propose the definition of “nanosheet” to be a nano-object with one external dimension in
the range from 0.3 to 30 nm and the two other, significantly larger, external dimensions.
Accordingly, to avoid conflictions with “nanosheet,” we suggest a change of the lower size
limit of “nanoplate” (approximately 1 nm) to 30 nm. Hence, the proposed definition of
“nanoplate” is a nano-object with one external dimension in the range from 30 to 100 nm
and the two other, significantly larger, external dimensions. Thus, nanosheets and nano-
plates are two-dimensional NMs. The “nanofiber” is defined as a nano-object with two
similar external dimensions in the nanoscale and a third, significantly larger dimension.
“Nanotube” refers to a hollow nanofiber, “nanorod” refers to a solid nanofiber, “nanowire”
refers to an electrically conducting or semiconducting nanofiber, and “quantum dot” refers
to a crystalline NP that exhibits size-dependent properties due to quantum confinement
effects on the electronic states.
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ISO/TS 80004-3:2010 Nanotechnologies—Vocabulary—Part 3: Carbon nano-objects. This
document defines terms such as graphene, fullerene, and carbon nanotubes. “Graphene”
is defined as a single layer of carbon atoms with each atom bound to three neighbors in
a honeycomb structure. This differs from bilayer, trilayer, and few-layer graphene sheets.
The chemical community often regards graphene oxide (GO) and reduced graphene oxide
(rGO) as graphene, which causes confusions and is actually incorrect. More important is
that these graphene-based materials have distinguishing properties.
