Fig. 2: DNA random synthesis.
Major procedural steps in synthesizing random DNA strands during solid state DNA synthesis. DNA building blocks are mixed prior to entering the binding substrate, where they start forming a strand of DNA based on their coupling efficiencies. The rate of the individual nucleotides couplings, ri, can be approximated by multiplication of the respective rate constant, ki and the nucleotide concentration, ci. During the process, individual nucleotides are shielded from binding to other nucleotides using protecting groups, ensuring that only one new random nucleotide can bind per DNA strand per iteration. Excess nucleotides that have not found a DNA strand to bind to are then removed from the synthesis chamber, and DNA strands are de-protected. To elongate each DNA strand to the desired length, the process of adding a mix of nucleotides, washing off left-over and subsequently de-protecting is repeated as often as required. Once the desired strand length of DNA has been reached, the DNA is cleaved from the synthesis support.
