3. Digital information storage on non-DNA polymers

The fundamental property that makes DNA suitable for storing digital data on a molecular scale is that this molecule is made up of a linear (unbranched) concatenation of building blocks or monomers of at least two species (four in the case of DNA). In principle, it is possible to represent '0' and '1' with just two monomers.

However, for some chemists, DNA is not the ideal molecular data carrier because :

• chemical reactions can modify its nitrogenous bases and therefore its information content, or modify its sugar ;

• DNA has only four different nucleotides, limiting information density;

• the bond between A and T is based on two hydrogen bonds, weaker than the bond between G and C, which is based on three hydrogen bonds. This can create hybridization...