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Radionuclide-Antibody Conjugation Service

Antibody-based RDC (Radionuclide Drug Conjugate), also named RAC (Radionuclide Antibody Conjugate), composed of radionuclide, chelator, linker, and the targeting molecule, is the most commonly studied RDC among all three types.

With wealthy experience in conjugation service, Rdcthera is glad to provide professional radionuclide-antibody conjugation service for you.

Overview of Radionuclide-Antibody Conjugation

As one kind of antibody-based radiopharmaceuticals, RDC with accurate bifunctional in cancer diagnostic and treatment represents one of the fastest growing fields in the pharmaceutical industry. Many novel bioconjugation approaches have been generated recently. Among all the bioconjugation methods, there are three most prevalent covalent bonds in radionuclide-antibody conjugation.

  • Amide Bond
    The most prevalent structures found in organic molecules, formed by amino and carboxyl groups of two adjacent amino acids.

Fig.1 Classical amide bond resonance.Fig.1 Classical amide bond resonance. (Mahesh S, et al., Molecules, 2018)

  • Thiourea Bond
    A classic conjugation planar bond with one C=S bond and two C-N bonds.

Fig.2 Diagram of chemical structure of thiourea bonds.Fig.2 Diagram of chemical structure of thiourea bonds.

  • Thioether Structure
    A common chemical structure containing two S-C bonds is widely used in bioconjugation.

Fig.3 Illustration of thioether bridge forming.Fig.3 Illustration of thioether bridge forming. (Balty C, et al., J Biol Chem, 2020)

Our Service

Since the conjugation site plays a significant role in RDC stability and pharmacokinetics-pharmacodynamics profile, the conjugation site should be chosen after careful consideration. As a leading company in radionuclide-antibody conjugation, Rdcthera, concentrating on RDC conjugation for years, can perform advanced conjugation technologies to develop a high-quality radionuclide-antibody conjugation service.

Types of conjugations Description
Lysine Conjugation With about 80 to 90 Lysine within one antibody, partial modification of Lysine shows no effects on the natural disulfide bonds nor the stability, biophysical properties, and affinity of the antibody. Consequently, Lysine is often selected as a well-established binding site in antibody conjugation, in which the nucleophilic NH2 group in Lysine reacts with the electrophilic N-hydroxysuccinimide (NHS) group of the linker.
Cysteine Conjugation Stochastic cysteine conjugation provides a flexible conjugation method that exploits the natural presence of native cysteine residues inside the antibody structure for RDC conjugation binding.
Unnatural Amino Acids Conjugation The unnatural amino acid residues, with unique chemical properties, can be introduced into the antibody, by adding to the culture medium during the fermentation process, to upregulate conjugation specificity and flexibility. As a reason for their immunogenicity, the most widely used unnatural amino acids are analogs of natural amino acids with unique groups.
Enzymatic Conjugation The enzymatically modified antibody, inserted with a specific amino acid sequence and recognized by a specific enzyme, can be used for site-specific antibody conjugation. We have several enzymes for site-specific enzymatic conjugation, including a formylglycine-generating enzyme, microbial transglutaminase, transpeptidase, tyrosinase, and so on.

Project Workflow

Fig.4 Project Workflow.

Why Choose Us

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Focused on RDC research for decades, Rdcthera is capable to provide high-quality and cost-effective RDC conjugation service for your special RDC project with the best scheme design and conjugation service to meet your demand.

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Rdcthera can provide all kinds of services through the whole RDC development process, including custom conjugation services according to your interests and lateral RDC analysis services.

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With an experienced research team and top-notched equipment, Rdcthera enable seamless scaling of RDC products from drug production to preclinical development. Collaborate across functional teams to promote your RDC development.

We are honored to share our wealthy experience and technology with you to support your RDC development project. Please contact us for more information.


  1. Mahesh, S., Tang, K. C., & Raj, M. (2018). Amide bond activation of biological molecules. Molecules, 23(10), 2615.
  2. Balty, C., Guillot, A., Fradale, L., Brewee, C., Lefranc, B., Herrero, C., ... & Benjdia, A. (2020). Biosynthesis of the sactipeptide Ruminococcin C by the human microbiome: mechanistic insights into thioether bond formation by radical SAM enzymes. Journal of Biological Chemistry, 295(49), 16665-16677.
For research use only. Not intended for any clinical use.

Rdcthera RDC

Rdcthera offers efficient, customized, and professional R&D services related to radionuclide drug conjugates.

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