Compositions For Use In Polynucleotide Sequencing

What is this patent about?

’962 is related to the field of polynucleotide sequencing , specifically addressing challenges in sequencing-by-synthesis (SBS) methods. These methods involve iterative cycles of nucleotide incorporation, detection, and removal of blocking and labeling moieties. Existing protocols often require multiple compositions for different steps, such as incorporation, scanning (detection), deblocking, and washing, which can complicate manufacturing, increase costs, and potentially reduce instrument reliability.

The underlying idea behind ’962 is to simplify the sequencing process by using a single buffer composition for both the detection (scanning) and post-cleavage wash steps . This composition includes both an antioxidant to protect the DNA during the detection step (where light-induced damage can occur) and a scavenger compound to neutralize reactive species generated during the deblocking step. The patent also highlights the use of 3,3′-dithiodipropionic acid (DPPA) as an effective scavenger.

The claims of ’962 focus on a polynucleotide sequencing method that uses a single buffer composition for both identifying the incorporated nucleotide and washing away the removed label and blocking moiety . This buffer contains both an antioxidant and a scavenger. Claim 10 specifically covers a method using 3,3′-dithiodipropionic acid (DPPA) as the scavenger in the wash solution.

In practice, the method involves incorporating a blocked and labeled nucleotide into a growing DNA strand, identifying the nucleotide using fluorescence or another detection method, chemically removing the label and blocking group, and then washing away the byproducts. The key is that the same buffer is used during the detection step to protect the DNA from light damage and during the wash step to neutralize reactive chemicals from the deblocking reaction. This reduces the number of buffers needed, simplifying the process and potentially improving reliability.

The patent differentiates itself from prior approaches by reducing the number of required buffer solutions and by demonstrating the effectiveness of DPPA as a scavenger. Traditional methods often use separate buffers for detection and washing, and may rely on less effective scavengers like lipoic acid. The use of DPPA, particularly in combination with a single buffer for both detection and washing, leads to improved sequencing performance, potentially enabling longer read lengths and faster cycle times by minimizing damage to the DNA and sequencing reagents.