23
drive of free markets appears to be an equally strong driver. It is
interesting to reflect that more than half of all the materials scientists
and engineers who have ever lived are alive today, and all of them
are pursuing better materials and better ways to use them. Of one
thing we can be certain: There are many more advances to come.
2.2 NANoMAteriAls ANd
NANostruCtures iN NAture
The timing of life arising on Earth was around 3.8 billion years ago
(see Figure 2.3). Since then life has learned to reproduce, live under
extreme toxic conditions, transform sunlight into oxygen, live
underwater, fly, and eventually think, talk, and show emotions. As
humans, we have constantly tried to supersede and control nature.
However, so far we have spent little time trying to do things the
way nature does. In other words, humans have not shown interest
or been too proud to mimic or at least have not been motivated
by nature’s millions of years of evolution. This is somewhat strange,
because nature is undoubtedly the most experienced and tested
laboratory ever available to us and capable of making sophisticated
materials, capturing energy, self-healing, and storing information
with incredible efficiency. Interestingly, most of what nature does
takes place at the nanoscale.
Perhaps the best-known biological example of such molecular
machinery is the ribosome, which is a remarkable nanoscale assembler. The role of the ribosome is to act as a factory of proteins by
combining amino acids together in a very specific order. A typical
ribosome is located in an aqueous solution surrounded by thousands of solutes. The work is difficult. The ribosome must identify
among 60 possible options a specific transfer RNA, a task that
demands precision at the nanoscale (Figure 2.4). In this fashion, the
ribosome machine can assemble proteins at a frequency of 20 Hz
and an error rate of 10
−3
. Thus, ribosomes can manufacture, with an
accuracy greater than 99.9%, linear strings of aminoacids of great
length, which then produce three-dimensional protein structures.
Another beautiful example of the role of nanostructures in the
world’s daily routine is photosynthesis. Every green plant and photosynthetic bacteria can take carbon dioxide, water, and sunlight
(the fuel) and transform them into oxygen and sugar, a process that
is accomplished with an amazing efficiency of around 95%. In the
case of green plants, everything happens inside the so-called chloroplasts. These units, which are responsible for the green color of
Figure 2.3
Earth’s clock of life. (Adapted from Peter D. Ward
and Donald Brownlee, The Life and Death of
Planet Earth: How the New Science of Astrobiology
Charts the Ultimate Fate of Our World, Times Book
Publisher, 2003.)
First life
12
1
2
3
4
5
6
7
8
9
10
11
(Billions of years)
Oxygen rises in
atmosphere
Now
Ocean
lost to space?
Age of plants and
animals
4
5
Figure 2.4
The ribosome assembler first selects from among
60 possible transfer RNAs (tRNA) one that allows
a particular amino acid to bind into the key
(Condon) of the messenger RNA (mRNA). The
ribosome continues to assemble in this fashion
until a particular protein is produced. (Adapted
from P. Ball, Designing the Molecular World:
Chemistry the Frontier, Princeton University Press,
1994.)
Amino
acid
tRNA
mRNA
Peptide
bond
Peptide
chain
Growing protein nanoproduct
Ribosome
assembler
strand
Nanomaterials and Nanostructures in Nature
drive of free markets appears to be an equally strong driver. It is
interesting to reflect that more than half of all the materials scientists
and engineers who have ever lived are alive today, and all of them
are pursuing better materials and better ways to use them. Of one
thing we can be certain: There are many more advances to come.
2.2 NANoMAteriAls ANd
NANostruCtures iN NAture
The timing of life arising on Earth was around 3.8 billion years ago
(see Figure 2.3). Since then life has learned to reproduce, live under
extreme toxic conditions, transform sunlight into oxygen, live
underwater, fly, and eventually think, talk, and show emotions. As
humans, we have constantly tried to supersede and control nature.
However, so far we have spent little time trying to do things the
way nature does. In other words, humans have not shown interest
or been too proud to mimic or at least have not been motivated
by nature’s millions of years of evolution. This is somewhat strange,
because nature is undoubtedly the most experienced and tested
laboratory ever available to us and capable of making sophisticated
materials, capturing energy, self-healing, and storing information
with incredible efficiency. Interestingly, most of what nature does
takes place at the nanoscale.
Perhaps the best-known biological example of such molecular
machinery is the ribosome, which is a remarkable nanoscale assembler. The role of the ribosome is to act as a factory of proteins by
combining amino acids together in a very specific order. A typical
ribosome is located in an aqueous solution surrounded by thousands of solutes. The work is difficult. The ribosome must identify
among 60 possible options a specific transfer RNA, a task that
demands precision at the nanoscale (Figure 2.4). In this fashion, the
ribosome machine can assemble proteins at a frequency of 20 Hz
and an error rate of 10
−3
. Thus, ribosomes can manufacture, with an
accuracy greater than 99.9%, linear strings of aminoacids of great
length, which then produce three-dimensional protein structures.
Another beautiful example of the role of nanostructures in the
world’s daily routine is photosynthesis. Every green plant and photosynthetic bacteria can take carbon dioxide, water, and sunlight
(the fuel) and transform them into oxygen and sugar, a process that
is accomplished with an amazing efficiency of around 95%. In the
case of green plants, everything happens inside the so-called chloroplasts. These units, which are responsible for the green color of
Figure 2.3
Earth’s clock of life. (Adapted from Peter D. Ward
and Donald Brownlee, The Life and Death of
Planet Earth: How the New Science of Astrobiology
Charts the Ultimate Fate of Our World, Times Book
Publisher, 2003.)
First life
12
1
2
3
4
5
6
7
8
9
10
11
(Billions of years)
Oxygen rises in
atmosphere
Now
Ocean
lost to space?
Age of plants and
animals
4
5
Figure 2.4
The ribosome assembler first selects from among
60 possible transfer RNAs (tRNA) one that allows
a particular amino acid to bind into the key
(Condon) of the messenger RNA (mRNA). The
ribosome continues to assemble in this fashion
until a particular protein is produced. (Adapted
from P. Ball, Designing the Molecular World:
Chemistry the Frontier, Princeton University Press,
1994.)
Amino
acid
tRNA
mRNA
Peptide
bond
Peptide
chain
Growing protein nanoproduct
Ribosome
assembler
strand
Nanomaterials and Nanostructures in Nature