Custom Oligonucleotide Synthesis

Custom Oligonucleotides

Fimers are primers with proprietary chemical modifications that inhibit unwanted reactions during cycle sequencing (e.g., primer-dimer artifacts and non-specific PCR).

Pteridines are naturally occurring, highly fluorescent compounds that are structurally similar to purines and that were first isolated from butterfly wings in 1889. The pteridines developed by Hawkins and co-workers are incorporated into DNA through a deoxyribose moiety identical to that of native DNA with no “linker-arm” attachment involved.

Amino-modified oligonucleotides have been routinely employed in solid support and label (or functionality) attachment chemistries. The 5′-terminus of the oligonucleotide is normally the target end for modification because of the ease of incorporation as the last step in automated synthesis.

A disulfide thiol modifier is available for 5′-end modification. A variety of tether lengths holding the thiol moiety can be varied to space the oligonucleotide away at a defined distance.
    We also offer 2′- thiol modified oligonucleotides. A reporter molecule or reactive group can be spaced from a probe oligonucleotide through tethers of varying lengths to determine all feasible possibilities for the docking of two or more domains.

We also offer 2′-amino modified oligonucleotides through the use of our SUC/MOX precursor strategy. By using this methodology we can incorporate amino-modifiers internally (currently at pyrimidine nucleosides – C and U analogs) within the oligonucleotide.

Complex probes can be made to suit your assay design. A combination of two or more different fluorescent dyes and other reporter groups can be incorporated on the oligonucleotide. Please contact us for more details, or to request a quote.

Biotin is widely used for DNA/RNA detection/isolation due to the extremely high affinity of the biotin-streptavidin interaction (association constant 1015/M). Biotin moieties can be incorporated within the oligo at any position and multiple times if desired. We have long and super-long tethering arms for improved binding kinetics, increased binding capacity of large DNA fragments, and for accessibility to enzymatic events occurring at the solid-phase surface.

High purity RNA can be synthesized using standard monomers with established 2′-O-TOM protecting groups. Custom RNA has successfully been used in antisense and RNA interference technologies. Furthermore, we can modify the RNA at the 5′- or 3′-ends and within the oligo at the 2′-position of C and U if desired. Please contact us for more details or to request a quote.

Oligonucleotides having a high number of covalently attached functional groups can easily be synthesized using our MOX/SUC precursor chemistries.

We can synthesize oligonucleotides used for antisense and antigene applications. Please contact us for more details or to request a quote.


Fidelity Oligos LLC
7965 Cessna Ave
Gaithersburg, MD 20879



Phone: 301-527-0804
Fax: 301-527-8250