CHAPTER 2: Nanoscience and Nanotechnologies
Background
2.1. Nanoscience is the science of the very small.
A nanometre (nm) is one thousand millionth of a metre. A sheet
of paper is about 100,000 nm thick, a red blood cell is about
7,000 nm in diameter and an atom of gold is about 1/3 nm
wide. Three hundred million nanoparticles, each 100 nm wide,
could be fitted on to the head of a single pin.
2.2. The concept of nanotechnology was first
envisaged by Professor Richard P Feynman, winner of the Nobel
Prize in Physics 1965, in his 1959 lecture There's Plenty of
Room at the Bottom in which he explored the possibility of
arranging matter at the atomic level. The term 'nanotechnology'
was not coined however until 1974, when Professor Norio Taniguchi
of Tokyo Science University used it to refer to the ability to
engineer materials precisely at the nanoscale.
2.3. The advance of nanoscience picked up pace
in the 1980s and 1990s, with the development of tools that allowed
the observation and manipulation of matter at the nanoscale (such
as the scanning tunnelling microscope in 1982 and the atomic force
microscope in 1986). Nanotechnologies are now applied in a variety
of sectors such as the pharmaceutical and healthcare, automotive
and electronic industries. In 2000, the United States National
Science Foundation estimated that the market for nanotechnology
products as a whole would be worth over one trillion dollars by
2015. A report by the consultancy firm Cientifica in 2007, Half
Way to the Trillion Dollar Market?, concluded that the nanotechnology
market was on track to be worth one and a half trillion dollars
by 2015 (see Chapter 3).
Nanoscience and nanotechnologies
2.4. The properties of nanomaterials can differ
significantly from the properties they exhibit in their larger
form. For this reason, scientists across a range of disciplines
have sought to understand nanomaterials and to apply them in novel
ways. In 2004, the Royal Society and Royal Academy of Engineering
published a report entitled Nanoscience and nanotechnologies:
opportunities and uncertainties ("the RS/RAEng 2004 report")
in which 'nanoscience' is defined as:
"the study of phenomena and manipulation of
materials at atomic, molecular and macromolecular scales, where
properties differ significantly from those at a larger scale";
and 'nanotechnologies' as:
"the design, characterisation, production and
application of structures, devices and systems by controlling
shape and size at the nanometre scale".[1]
2.5. In the context of the food sector, nanoscience
is the passive observation of food to understand better how it
is structured and behaves at the nanoscale, while nanotechnologies
are the more active manipulation of food to produce a desired
effect.
2.6. The diversity of nanomaterials makes their
general regulation and risk assessment particularly challenging.
There is no universally accepted regulatory definition of nanomaterials
or nanotechnologies, and the difficulties caused by this were
drawn to our attention by a number of witnesses.
Nanomaterials and nanoscale properties
2.7. The RS/RAEng 2004 report suggests that there
are two main reasons why materials at the nanoscale exhibit different
properties from their larger form. First, nanomaterials have a
relatively bigger surface area (see Table1), and as a result they
may be more chemically reactive. Secondly, nanoscale materials
can begin to display quantum effects in which the electronic,
magnetic and optical behaviour of the material may alter. For
example, the melting point of silver is approximately 960oC,
yet nanosized silver can be melted with a hairdryer (Q 89),
while titanium dioxide, used in its bulk form as a whitening agent,
becomes transparent at the nanoscale (pp 100-103).
2.8. Whilst the quantitative meaning of 'nano'
is clear—namely, a thousand millionth—the defining
feature of the point at which a particular material can be said
to be a nanomaterial is not strictly quantitative: it is the point
at which a material demonstrates a novel functionality as a result
of its small size. Since this point varies between different types
of materials, there can be no single size limit beneath which
materials are automatically classified as 'nano'. Typically, novel
properties begin to appear as a material's dimensions drop below
100nm but this is not invariable—one material may exhibit
changed properties at 200nm while another may remain unchanged
at 90nm.
TABLE 1
Nanomaterials: Particle number and surface
area over mass and volume
| Particle diameter (nm)
| Number of particles per gram
| Total surface area cm2 per gram
|
| 1000 | 1.9 x 1012
| 60,000 |
| 100 | 1.9 x 1015
| 600,000 |
| 10 | 1.9 x 1018
| 6,000,000 |
Source: Food Safety Authority of Ireland, The
relevance of Food Safety of Applications of Nanotechnology in
the Food and Feed Industries, 2008, p.41
2.9. The term nanomaterial is a complex one.
A nanomaterial may be produced that is nanoscale in one dimension
(for example, a very thin film), two dimensions (for example,
a carbon nanotube) or three dimensions (for example, a nanoparticle).
It should be noted that although witnesses often simply referred
to 'nanoparticles', in many cases their comments applied to the
whole range of nanomaterials. And, although we refer generically
to nanomaterials, in reality they cannot easily be grouped into
a single class because they offer a vast range of different properties
depending on their chemical and physical composition, and other
than their size may not have any common features.
Scope
2.10. Throughout this report we refer collectively
to nano-sized structures as nanomaterials. Unless stated otherwise,
our comments about applications of nanomaterials refer to the
use of nanoscale substances that do not naturally occur in food
products, or natural food materials that have been deliberately
engineered at the nanoscale. We do not include in this category
nanoscale substances naturally present in food, or those created
through traditional manufacturing processes (see paragraph 1.4
for examples). We discuss these issues further in Chapter 5.
1 Royal Society and Royal Academy of Engineering (RS/RAEng),
Nanoscience and nanotechnologies: opportunities and uncertainties,
2004, p 5. Back
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