With the development of various next-generation sequencing platforms, there has been a substantial reduction in costs, and increase in throughput of DNA sequencing.  However, the majority of the sequencing technologies rely on PCR-based clonal amplification of the DNA molecule in order to bring the signal to a detectable range. Sequencing of amplified clusters, or bulk sequencing in such a propose a read length-dependent phasing problem.   During each cycle, not all of the molecules within the bulk have successful incorporation of an additional nucleotide.  With increased sequencing cycle, the signal of the lagging molecules will eventually overwhelm the true signal.  The phasing problem is a major limitation for the read lengths of the next-generation sequencing technologies.  Therefore, there is an increased interest in developing single-molecule sequencing technologies, where no amplification is required. This not only shortens the preparation time for the sequencing libraries, it also has the potential to achieve much longer read lengths, as the lagging molecules with failed extensions can be ignored or considered separately.  Previously known single-molecule sequencing technologies include Nanopore sequencing (Oxford Nanopore),
SMRT sequencing (Pacific Biosciences), and Heliscope single molecule sequencing (Helicos Biosciences).