Custom Circular Oligonucleotide Synthesis

Circular oligonucleotides are essentially covalently closed strands of DNA or RNA which are being heavily investigated as a new class of potential therapeutic agents. As a professional oligonucleotide synthesis company, BOC RNA provides circular oligonucleotide synthesis services to meet the diverse needs of our customers.

Overview of Circular oligos

  • What is CON

Circular oligonucleotides (CON) are covalently closed strands of DNA or RNA in essence. They usually have nucleotide loops at both ends with high melting transition temperature values. This strong secondary structure makes such circles easier to construct than those lacking a strong internal structure, since linear circular precursors fold themselves into a dumbbell shape with a cut in solution. Compared with the linear structures, these circular oligonucleotides have higher affinity, sequence selectivity, and are more resistant to nucleases, endowing them resistant to degradation by many cellular DNA and RNA decay mechanisms.

Circular oligonucleotides (trimer through hexamer).Fig. 1 Circular oligonucleotides (trimer through hexamer). (Smietana M, 2002)

  • How to Synthesize CON

Circular DNA or RNA oligonucleotides can be chemically synthesized from partially protected linear precursors using solution and solid-phase synthesis methods. After removal of linear DNA, circular oligonucleotides were purified by denaturing polyacrylamide gel electrophoresis (PAGE). Circularity was determined by exonuclease cleavage. Finally, an independent QA procedure was used to ensure the highest quality of each cyclic oligonucleotide.

Synthesis of circular oligodinucleotides.Fig. 2 Synthesis of circular oligodinucleotides. (Smietana M, 2002)

  • Applications of CON
  • Molecular cloning
  • Phage therapy
  • Nanotechnology
  • Delivery vectors for miRNAs
  • Diagnostics
  • DNA polymerase inhibition
  • Rolling circle amplification (RCA)

Content of Custom CON Synthesis

For additional information regarding custom circular oligonucleotides synthesis, please feel free to contact us.

  • Custom circular DNA oligonucleotides synthesis
  • Custom circular RNA oligonucleotides synthesis
Length35 to 200 mers
  • 100 pmole
  • 200 pmole
  • 500 pmole
PurificationHPLC or PAGE
ValidationMS and PAGE analysis plus additional QA procedures

Services Process of Custom CON Synthesis

  1. Requirement Confirmation - Communicate with customers to confirm their needs and technical requirements, including nucleotide sequence, loop size, pairing method, etc.
  2. Synthesis Design - Design the synthesis protocol and evaluate it according to the customer's needs and claims, including nucleotide synthesis, cyclization reaction, purification and other steps.
  3. Nucleotide Synthesis - Synthesizing the desired nucleotide monomers using chemical or enzymatic catalytic methods, and obtaining high purity nucleotides after several rounds of reactions and purification.
  4. Cyclization Reaction - The nucleotides are linked into rings to form cyclic oligonucleotides using chemical or enzymatic catalysis according to the design scheme.
  5. Purification and Analysis - The synthesized cyclic oligonucleotides are purified and analyzed to ensure their quality and purity.
  6. Delivery and Service - The custom synthesized cyclic oligonucleotides are delivered to the customer by courier or other means, and good after-sales service is provided.

Custom Circular Oligonucleotide Synthesis


  1. LI J; et al. Circular Nucleic Acids: Discovery, Functions and Applications. Chembiochem. 2020, 21(11): 1547-66.
  2. Smietana M; et al. Efficient and simple solid-phase synthesis of short cyclic oligodeoxynucleotides bearing a phosphorothioate linkage. Angew Chem Int Ed Engl. 2002 Oct 4; 41(19): 3704-7; 3523.
* Only for research. Not suitable for any diagnostic or therapeutic use.
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