Diamond As Life Giver

The origin of life has been a mystery to scientists for a long time. The abundance in water has allowed the life to prosper on Earth, but the sudden appearance of prokaryotes (e.g. bacteria) immediately after the solidification of Earth's crust about 3.8 billion years ago was a surprise. Although no mechanism was given, the hypothesis of panspermia hinted that the precursor of prokaryotes might be formed outside the solar system before the Earth was formed. These building blocks of life might have showered the early sky when the atmosphere contained mostly carbon dioxide methane, and water vapor. Once the primordial broth on the Earth was taking shape with the precursors of life various forms of prokaryotes could be developed in a few hundred million years.

James Ferris of Rensselaer Polytechnic Institute surmised that clay minerals (e.g. montmorillonite) might serve the function of a template for assembling biomaterials. However, clay minerals are not stoichiometric stable so they may not reproduce the results reliably. Recently, German scientists speculated that water wetted diamond could have jump-started the first life on Earth (http: news.yahoo.com/s/ livescience/20080726). Their model was based on electrical conductivity of hydrated diamond surface.

A living organism requires both the blue print and duplicating mechanism for making and maintaining itself. The blue print

Diamond Nanotechnology: Synthesis and Applications by James C Sung & Jianping Lin

Copyright © 2009 by Pan Stanford Publishing Pte Ltd



used most today is based on DNA. The manufacturing house and maintainence facilities are based on protein. These machineries are overly complicated for the first life to acquire naturally by chance. However, according to the hypothesis of RNA world, the primitive RNA could be the precursor of both DNA and protein. Microscopic RNA could duplicate itself although unreliably. A folded RNA molecule might also assemble amino acids for making proteins. In fact, RNA of virus size has been "lubricant" of cells. Without them to run around and to fix things, a cell will die of functional deterioration.

For all complicated structures formed in nature, they have to be assembled from atoms and molecules. However, this bottom up approach works only if certain building blocks are preformed. In the case of RNA or protein, the building blocks themselves are rather complex. For example, all nucleotides contain aromatic carbon rings with conjugated sp2 bonds (e.g. benzene). Moreover, all proteins are polymers with a back bone made of complementary spl, sp2, and sp3 bonds. If carbon derived molecules are formed, further additions or modifications of them can be easier. Thus, the precursor of life is logically made of carbon derived molecules as building blocks.

Many scientists have been baffled with the question that the evolution of living organism have been able to defy the second law of thermodynamics. Lord Kevin once said that the second law was the law of laws so it could not be modified. In fact, the very reason of Big Bang is based on the entropy increase associated with space expansion. Consequently, the second law violating life evolution seems impossible. However, the second law may be overcome if the system is open. For example, a refrigerator is capable to pump heat uphill from a cold place a hotter environment. Living organism are open systems so they can excrete entropy by metabolism.

However, the building blocks of life precursors cannot metabolize, so where its energy may come from? The answer lies in the potential energy of gravity. The flexible carbon bonding acts like a spring the provide the uphill driving force. The carbon spring was made by sintering in a supernova that was compressed by gravity. As discussed in the previous chapter, carbon is the most prevailing solid in the universe. The carbon element was made in a giant star with heat generated by the consolidating of gasses. In essence, diamond was formed at the core of stars.

The diamond core could explode as supernova. The gigantic diamond was shattered as nanodiamonds. As the temperature was still hot during the rapid decompression process, most nan-odiamond transformed into graphite with disintegrated carbon rings. Moreover, many carbon particles are forming onions, bucky balls, carbon nanotubes, carbon blacks, hydrocarbon molecules, CNO compounds, and carbon soots. Such carbon derivatives may be found in interstellar dusts. They may also be incorporated in comets and meteorites.

Based on the above top down model, the potential energy of gravity was stored as chemical energy of carbon. The dexterity of carbon bonding (i.e. sp1, sp2, sp3) allows the release of carbon energy to facility the formation of proto RNA and protein. However, even with the availability of the carbon derived molecules, they are still difficult to be assembled in the form of biomaterials. But this problem is solved once again by the presence of diamond. As the back converted diamond can not only provide the raw materials for organic chemistry, it may also act as versatile mold for assembling biological molecules.

Nanodiamond are clustered carbon atoms with both graphitic (sp2) and diamondoid (sp3) bonds. The two types of bonds can be interchangeable, for example, the stretched (111) face of diamond is a graphene plane. In reverse, the puckered graphene may become a diamond surface. This interchangeability allows nanodi-amond particles to be flexible templates, particularly around the curved surface where electrons are unstable. If diamond played a role in coercing the formation of organic molecules, it could do so everywhere in the universe, even before the solar system began to condense about 5 billion years ago.

Diamond could be the most abundant solid already when the first stars were formed more than ten billion years ago. The density of the universe was much higher then so massive stars were commonplace. These jumbo stars were active nuclear fusion bombs for synthesizing heavier atoms. Some of the big stars exploded as supernovae and they spewed diamond debris to mix with interstellar dusts. Most stars we see today were formed later on in the cinders of early stars.

The new stars were not as massive, but many of them could synthesis carbon at core if the temperature reached 15 million degrees centigrade. After exhausting most lighter elements by nuclear synthesis, a star might collapse and it cooled down. Subsequently, carbon vapors in the interior of the star condensed to form liquid and it eventually solidified to become crystalline diamond. Hence, many dead stars known as white dwarfs may contain a diamond core. The colder dwarf often pulsates with a characteristic frequency that reveals diamond as the major internal constituent. In 2004, astronomers identified BPM37093 as such a diamond star. It is located only 17 light years away in Constellation Centaurs visible from the southern hemisphere of Earth. It was named Lucy after the Beatles' song "Lucy in the Sky with Diamonds". Our Sun may join Lucy as another diamond star when it runs out the fusion fuel about 10 billion years in the future.

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