Phosphoramidites (often abbreviated as amidites) are building blocks used in chemical synthesis of oligonucleotides. Automated oligo synthesizers complete sequential chemical reactions using phosphoramidites to produce the nucleotide chains of synthetic oligos. Typically, oligo synthesizers add phosphoramidites from the 3′ to 5′ direction, the opposite of enzymatic synthesis. One advantage of synthesizing oligonucleotides chemically is that modifications or labeling of the building blocks necessary for final oligo function can be introduced easily.
Thermo Fisher Scientific offers a broad range of phosphoramidites, which are supported by:
- Technical expertise—over 40 years of partnership, customization, and scale-up experience
- Secure and consistent supply—5x capacity expansion in 2022 to enable emerging diagnostic assays and oligo therapeutics
- Service excellence—48 hours or less response to orders, >98% delivery to customer at promised date*
- Flexible packaging—custom and bulk packaging available upon request
- Quality manufacturing and documentation—batch-to-batch consistency, minimal level of reactive impurities, and analytical documentation support
- Refined quality—ISO 9001:2015–certified quality management system that has been refined in partnership with our customers since 1995
* May not be available in all regions
Quick tour of our manufacturing facility for phosphoramidites
At the Thermo Fisher facility in Milwaukee (WI, USA), we have been customizing and scaling up high-quality phosphoramidites for oligonucleotide synthesis, for over 40 years.
Purpose-built Thermo Scientific phosphoramidites
Explore the following categories of phosphoramidites to fit your varying needs of oligonucleotide manufacturing for the development of therapeutic, diagnostic, and research applications.
Find phosphoramidites with deoxyribonucleobases for synthesis of DNA oligos for diagnostic assays and therapeutic applications.
Find phosphoramidites with ribonucleobases for synthesis of RNA oligos for diagnostic assays and therapeutic applications.
Find phosphoramidites with common base modifications—such as 2′-MOE, 2′-OMe, and 2′-fluoro—for synthesis of antisense oligos and siRNAs for therapeutic applications.
Find phosphoramidites with fluorescent labels for synthesis of oligos for detection in molecular assays and microarrays.
Find phosphoramidites with modifications (e.g., 5m-dC, N6-Me-dA, N4-Ethyl-dC, 8-oxo-dG) for synthesis of primers, probes, or oligos for structural and mutagenesis studies.
Find phosphoramidites with linkers at 3′, 5′, or internal positions for NHS ester conjugation; and spacers to increase the distance between functional groups as well as to provide conformational support.
Find DNA succinates for the derivatization of controlled pore glass, polystyrene, or other supports used in solid-phase oligo synthesis.
Options for base protection groups and package formats
Depending on your selected phosphoramidites, they may be available in one or more of these options. Please contact us if you do not find one that meets your needs.
Base N-protections to choose depending on your deprotection methods, their sensitivity to base hydrolysis, and their reactivity with tags and labels:
- Benzoyl (Bz)
- Isobutyryl (iBu)
- Isopropyl-phenoxyacetyl (iPrPAC)
- Phenoxyacetyl (PAC)
- Acetyl (Ac)
- Dimethylamino-formamidine (DMF)
- No base protection
Package formats to accommodate your synthesis scales, synthesizers, and solvation methods:
- Applied Biosystems synthesizer, AKTA synthesizer, MerMade synthesizer, Expedite synthesizer, and others
- Screw cap, serum vial, bulk options, among others
- Threading finish and neck size
- GL-45, 38/430, 20 mm, 28/400, and more
- Fill volumes
- Packaging materials
- Borosilicate glass; glass type I, II, and III; HDPE; PETG; and more
Examples of some available packaging options
Custom services for oligonucleotide chemistry
In addition to our Thermo Scientific phosphoramidites, we offer custom services for oligonucleotide chemistry tailored to fit your needs in diagnostic and therapeutic applications. We are fully set up to provide customization of our existing phosphoramidites, synthesis of new compounds, and development of oligonucleotide delivery chemistries. Simply fill out this short form with your interest so that our representative can explore available options with you.
Advanced project management
- Customer involvement
- Dedicated cross-functional project team
- Project planning and execution tailored to each custom request
- Manufactured in an ISO 9001–registered facility
- Thoroughly documented processes provide consistent product quality with batch-to-batch consistency
- Base or base protection modification
- Sugar modifications
- Changes to phosphitylation, or phosphitylation of custom molecules
- 5′ protection modification
Custom chemistries and capabilities
- Chemistries: phosphoramidite and custom organics
- Modifiers and linkers
- R&D to large-scale manufacturing
- Development of customized QC
- Customer-driven specifications
- Custom filling, labeling, and packaging
Phosphoramidite customization options
A. Dimethoxytrityl (DMT) substitution with alternate protecting groups
B. Base = A, C, G, T, or U protection modifications or base modifications
C. Sugar modifications and protection options
Request custom services
TheraPure services—access to customized materials for producing nucleic acid therapeutics
Hear our scientists discuss Thermo Fisher's Milwaukee facility history, customer partnership, manufacturing process, quality improvement, mitigation of supply chain issues, and our recent response to global needs.
For Research Use Only. Not for use in diagnostic procedures.