Ion Semiconductor Sequencing is a type of DNA sequencing that detects the presence of hydrogen ions during DNA polymerization.

How It WorksEdit

A microwell contains the template DNA. The template DNA is introduced, where dNTPs are added via polymerase. If the dNTP is complementary and successfully binds to the te
500px-DNTP nucleotide incorporation reaction.svg

The addition of complementary dNTP results in the release of hydrogen ions and pyrophosphate.

mplate leading strand, then hydrogen ions and pyrophosphate are released. Hydrogen ions are dectected using an ISFET (ion-sensitive field-effect transistor) ion sensor, which can detect pH changes.This sensor is located underneath the microwells. The benefit of using this type of DNA sequencing include low costs and DNA can be quickly sequenced, but too many hydrogen ions can be released at the same times if long repeats are present on the DNA template strand. This is because numerous of dNTPs can be added to this long repeat.
800px-DNTP incorporation hydrogen magnitude.svg

The release of hydrogen ions are detected using the ISFET ion sensor. Higher intensity indicates that the same bases are next to each other, resulting in higher Hydrogen ion release.