The last decade has seen dramatic advances in sequencing technology that have relied on highly-parallel optical sensing of polymerisation reactions. These advances have substantially reduced sequencing costs, however further reduction in cost is limited by the dependence of these platforms on photo-receptive sensors and their associated reagents. In 2011, Life technologies began distribution of the Ion Torrent Personal Genome Machine (PGM). The PGM leverages advances in semi-conductor technology and ion-sensitive transistors to sequence DNA using only DNA polymerase and natural nucleotides, with each polymerisation event recognised by pH changes alone [1].
