Sequencing technique may revolutionise data storage

Chemists at Reading University have developed a way of ’reading’ the molecular sequences of a synthetic polymer, which could be used to represent digital data.

DNA stores genetic instructions in the form of different sequences of base molecules. In a similar way, the sequences in synthetic polymers made from two types of molecule could be equated with the ones and zeros that make up binary digital code.

The Reading team found specific sequences of monomers in a copolyimide could be recognised by their interactions with additional molecules known as ’tweezers’, which match the shape and electrical charge of sections of the sequence.

‘The polymer sits in solution with the tweezers, which come to rest and bind most strongly when they match,’ Howard Colquhoun, team leader and professor of materials chemistry, told The Engineer.

‘We found in practice that the tweezer molecules sit next to each other in the sequence,’ he added. This meant the team could read much longer sequences than it had expected.

The team also found a different type of tweezer would start reading the sequence at a different point, allowing a new set of data to be read from the same chain and increasing the amount of information it could potentially store.

While the polymers created in the team’s experiments only equalled a few bits of data, Colquhoun said in principle this method could be used to store as much as 100 billion gigabytes in 1g of polymer.

‘We can’t yet write information into the polymers, and actually nature doesn’t write DNA either – changes occur through random errors. But we have started to see how we would chemically write information by working on the density of the polymer.’

The team is now working on a way of reading the sequence at the molecular level using a surface analytical technique, rather than looking at the average behaviour of all the polymer molecules.

The research was funded in part by a £360,000 grant from the EPSRC. A further £400,000 has been promised by the EU to develop the technology further as part of a larger collaboration with Nottingham and Liverpool and five other European universities.