Date: 27 February 2025 | Category: Headline News, News
We are excited to be able to share the work of Scientists at Novo Nordisk who have applied flow chemistry to enhance the cleavage of oligonucleotides. The improvements reported are:
- Reducing the time for cleavage and complete deprotection to less than 3 minutes.
- Eliminating the risks associated with batch reactors having pressurised headspace.
- Producing repeatable results and crude cleaved oligonucleotides at higher concentrations.
- Improving the safety and simplifying the route to scale-up.
Cleavage of oligonucleotides is the process of removing the oligonucleotide from a solid support. The traditional batch method involves heating an aqueous solution of ammonia or methylamine, or a mixture of both with the oligonucleotide-resin for over 15 hours. The oligonucleotide is both cleaved from the resin and the protecting groups are removed.
Cleavage and deprotection is a critical step in solid-phase oligonucleotide synthesis as impurities can be introduced. Minimising these impurities requires fine control of temperature and reaction time.
This lengthy batch process is necessary to ensure complete cleavage and removal of protective groups but often results in scalability issues and potential safety risks due to the high pressures generated within the headspace of the reactor. The high pressures are generated when the volatile reagents (ammonia or methylamine) are heated, reducing its concentration in the solution phase
Flow chemistry addresses these challenges by pumping the cleavage solution through a heated reactor containing the oligonucleotide-resin. A second heated tubular reactor is connected in series for deprotecting the oligonucleotide before collection. Both reactors are maintained under sufficient pressure to prevent the vaporisation of the volatile reagents. There is no head space, all the reagent remains in the liquid phase. This approach drastically reduces reaction times to less than 3 minutes, regardless of scale. Safety is improved by eliminating the need to handle pressurised batch reactors. Additionally, the flow method yields concentrated crude oligonucleotide solutions, simplifying downstream processing.
The Scientists from Novo Nordisk used a Vapourtec R-Series Flow Chemistry system to undertake this excellent research. We are grateful that the data has been made available to Vapourtec in the form of an application note. This application note is of value to all researchers having an interest in the cleavage of oligonucleotides.
This advancement represents a significant step forward in oligonucleotide synthesis, offering a safer, faster, and more efficient method for cleavage and deprotection of oligonucleotides.
Vapourtec would like to thank Novo Nordisk Copenhagen, DK, and especially Alexander Davies for the ideation, lab-work and analysis presented in this application note.