Synthesis of chemical tags

A method of storing binary bits in a biological molecule, the method comprising the steps of:

• providing a substrate having defined therein an array of periodically-spaced regions capable of defining a writable segment in DNA at one or more locations where said periodically spaced regions in contact with said DNA;
• providing at least one double stranded DNA molecule on said substrate thereby defining a plurality of said writable segments in said DNA at one or more locations where said periodically spaced regions in contact with said DNA;
• writing binary bits to said writable segments by denaturing at least one of said writable segments;
• and
• attaching at least one insertion compound to at least one nucleotide in said at least one writable segment;
• wherein the information stored in said binary bits is defined by the presence or absence of said insertion compound.