Application of Antibody-Oligonucleotide Conjugates (AOC)

Antibody-oligonucleotide conjugates (AOCs) are a novel class of bioconjugates that have obtained continual attention in different fields of modern biotechnology. This approach combines the properties of two modules, exceptional targeting abilities, and antibody biodistribution profiles, in addition to an extensive scope of oligonucleotide (ON) functional and structural roles. AOCs now represent an important milestone in the development of biotechnological applications, including imaging, detection, and therapeutics.

Creative Biolabs is a biotechnology company focusing on discovering and developing novel and targeted drug products such as AOCs and antibody-drug conjugates (ADCs). We provide the complete set of AOCs development services targeting various targets from design to characterization to meet your specific requirements.

Applications of AOCs

So far, AOCs have been widely used in numerous fields such as detection or therapeutic applications. Generally, the detection methods include immuno-PCR (iPCR), proximity extension assay (PEA), electrochemical proximity assay (ECPA), DNA-PAINT imaging, and protein arrays. As for therapeutic applications, AOCs have been used as therapeutic agents containing payload and as a pretargeting module for radionuclide therapy and imaging. In these cases, the antibody specifically targets the site of interest, and the linked oligonucleotide exerts its functionality either as a gene-silencing or a pretargeted therapeutic agent.

Fig.1 Antibody-oligonucleotide conjugates (AOCs) are used in imaging, detection, and therapeutics. (Dovgan, 2019)

• AOC for Immuno-PCR (iPCR)

In this technique, the DNA primer is covalently conjugated to the antibody immunoassay probe and amplification is performed using circular DNA. The result of amplification is an AOC containing a long DNA molecule, in which hundreds of circular DNA sequences can be easily visualized by fluorescence after hybridization with oligonucleotides labeled by complementary fluorescent groups.

• AOC for Proximity Extension Assay (PEA)

The approach is based on the use of two AOC probes, one of which possesses 3′-linked double-stranded DNA, containing a short overhang at its 5′-end. This overhang is used to be complementary to the 5′-linked single-stranded DNA bound to the partner probe. During incubation with mutually recognized samples, hybridization of the overhanging fragments becomes advantageous and the resulting hybridization of double-stranded DNA can be extended by DNA polymerase. This results in a full-length amplicon that can be detected and quantified by qPCR.

• AOC for Electrochemical Proximity Assay (ECPA)

The method consists of binding molecules (initially aptamers) and ON-tags. Upon the formation of a cooperative complex with a protein target causing a redox-active moiety such as methylene blue closer to a gold electrode, it can produce a redox current. The current can be quantified with high precision and directly depends on the concentration of the target.

• AOC for Super-Resolution Microscopy

In this application, the labeling strands are specifically designed to form stable binding during image acquisition, thus allowing the sequential imaging of different antibody targets. Significant in situ signal amplification can be achieved by a more elaborated ON design, which is used as a docking site for multiple fluorophore-bearing DNA imager strands, to realize controllable multiplexed signal amplification.

• AOC for DNA-PAINT Imaging

This method is developed to overcome the resolution limit of conventional light microscopy. The technique is often based on the blinking of fluorophores (sequential activation), which can be observed one at a time. This process of sparse activation is repeated until a sufficient number of position measurements is accumulated to allow the localization of the spatial coordinates of fluorophores with subdiffraction precision.

• AOC for Protein Arrays

This approach is to generate antibody arrays for the diagnostics of antigens and whole cells on chips. The indirect immobilization of proteins and antibodies has been proven to work under mild conditions, ensuring protein integrity.

• AOC for Therapeutics

Based on the important role of ONs in gene regulation, gene silencing, protein synthesis, and enzyme inhibition, a variety of therapeutic applications have been proposed. The bioactive ONs have been combined with mAbs to achieve better targeting into desired tissues or cells. AOCs are showing promise used as gene-silencing anticancer and antiviral agents, enhancing agents for radiotherapy, or tools for studying antibody internalization and metabolism mechanisms.

Fig.2 Schematic representation of AOC use in (a) antibody arrays; (b) therapeutic; and (c) pretargeting applications. (Dovgan, 2019)

Comprehensive AOC Development Services at Creative Biolabs

Based on years of experience in antibody-related products development and services such as antibody production and bioconjugation, Creative Biolabs offers a full range of AOCs development services for various applications based on previous mature technology and platforms. We believe our established platform will deliver high-quality services and products to suit your research objectives, budget, and timeline requirement. To further discuss your unique AOCs development demands or to request a proposal, please contact us.

Reference

1. Dovgan, I.; et al. Antibody-oligonucleotide conjugates as therapeutic, imaging, and detection agents. Bioconjugate chemistry. 2019, 30(10): 2483-2501.

For Research Use Only. NOT FOR CLINICAL USE.