Just as a book's information is made up of a linear sequence of letters, so the information needed for living things to function and reproduce is embodied in a linear sequence of chemical units that make up chains of DNA and RNA, where enormous amounts of information (the 'genome') is stored in a very small space to direct the molecular processes of life.

The Reading team, led by Howard Colquhoun (right) Professor of Materials Chemistry, has designed and synthesised short sequences of a synthetic, information-bearing, polymer chains, showing for the first time that many of the features of biological information processing can be reproduced in such chains. The paper is published in Nature Chemistry.

Long term, researchers believe this could revolutionise future of digital information, with synthetic polymer systems allowing information densities several million times higher than current systems.

Crucial to the work is creation of the tweezer-shaped molecules that pick out sequence-information along a polymer chain. The two arms of the tweezer ‘feel’ the different sequences available and clamp on to the chain at the precise sequence where the chain structure and tweezer structure are most complementary.

Several tweezer molecules can bind next to one another on the polymer chain, allowing them to ‘read’ and translate extended, long-range polymer-sequence information. Most notable is that different types of tweezer molecules start reading at different positions on the chain.

This selectivity means different types of information can be read from the same sequence increasing the amount of information available.
 “This type of process is paralleled in the processing of genetic information," says Professor Colquhoun. "In the future, we plan to develop methods for writing new information into the polymer chains with the long-term aim of developing wholly synthetic information technology, working at the molecular level.

Quantum entanglement 'glue'
At the National University of Singapore a group of physicists led by Elisabeth Rieper claim that DNA may be held together by quantum entanglement, the process in which a single wavefunction describes two separate objects. When this happens, these objects effectively share the same existence, no matter how far apart they might be.

The researchers have constructed a simplified theoretical model of DNA in which each nucleotide consists of a cloud of electrons around a central positive nucleus. This negative cloud can move relative to the nucleus, creating a dipole. And the movement of the cloud back and forth is a harmonic oscillator.

When the nucleotides bond to form a base, the clouds must oscillate in opposite directions to ensure the stability of the structure. The researchers query what happens to oscillations, or phonons, when the base pairs are stacked in a double helix.

Without any effect from outside heat, they posit "The chain of coupled harmonic oscillators is entangled at zero temperature," and go on to show that the entanglement can also exist at room temperature. This is possible because phonons have a wavelength similar in size to a DNA helix, this allows standing waves to form, known as phonon trapping. A similar kind of phonon trapping causes problems in same size silicon structures.

Each nucleotide in a base pair is oscillating in opposite directions, this occurs as a superposition of states, so that the overall movement of the helix is zero. In a purely classical model, however, this cannot happen, as the helix would vibrate and shake itself apart. So in this sense, these quantum effects are responsible for holding DNA together.

The question is how to prove this?

Researchers admit that one line of evidence is that a purely classical analysis of the energy required to hold DNA together does not add up. Their quantum model provides the answer, but will need to produce successful experimentation to convince the biologists.

The paper also suggest that the entanglement may have an influence on the way that information is read off a strand of DNA and that it may be possible to exploit this.