Fluorescent markers of different colors were used for the four types of nucleobases, and then a laser light source was used to capture the fluorescent signals in order to obtain the gene sequence information of the DNA being tested.
Although this method was reliable, it was also no secret that it was expensive. The price of an instrument ranged from about $500,000 to $750,000, and the cost of a single test could be as much as $5,000 to $10,000.
In the latest gene sequencing instruments, chips have replaced traditional laser lenses, fluorescent dyes, and so on. The chip itself is the sequencer.
Through semiconductor sensors, the instrument directly detects the ionic currents produced during DNA replication.
When reagents enter the chip through the integrated fluidic channels, the densely packed reaction wells on the chip immediately become millions of micro-reaction systems.
