The quantity and wealth of information that can be gathered from sequencing data have increased tremendously from Sanger sequencing to next generation sequencing (NGS), while there is a precipitous drop in the cost of sequencing.1 Several new sequencing technologies have been developed in the recent years, with some enabling sequencing of even single DNA molecules. Sequencing using nanopores, tiny apertures on the cell membrane, offer several advantages over existing technologies that use sensitive optics or complex preparation methods to detect DNA sequences.
Nanopore technology offers several benefits, such as:
The technology combines the power of nanopores to distinguish between different biological molecules with a cost-effective semiconductor based electronic system. At the heart of the technology is the biological nanopore, a protein pore embedded in a membrane and the brains of the technology lie in the electronics of a semiconductor integrated circuit and proprietary tag chemistry. Electronic sensor technology embedded in the chip enables automatic membrane assembly and nanopore insertion while allowing for active control of individual sensors on the circuit. Each nanopore has a DNA replication enzyme, or polymerase, tethered to it and positioned near the pore entrance. This positioning is an integral component of the tag chemistry, which consists of modified nucleotides, each carrying tags of a different size specific to each of the four bases that make up the genetic code.
As the polymerase incorporates these modified nucleotides into the growing copy of the DNA template strand, its corresponding base specific tag is captured by the nanopore. When held within the barrel of the nanopore, each of the four distinct tags partially blocks the channel creating a unique signal. The result is a highly accurate tag-specific signature allowing for DNA sequence analysis at a single molecule level with single base resolution.