AOC for Protein Arrays

Protein arrays are traditionally made by random absorption of proteins to the array surface, potentially limiting the amount of properly oriented and functional molecules. Creative Biolabs has developed DNA-encoded antibody microarray utilizing site-specific antibody-oligonucleotide (ON) conjugates (AOCs) that can be used for cell immobilization as well as the detection of genes and proteins. This technology allows the facile generation of antibody microarrays while circumventing many of the drawbacks of conventionally produced antibody arrays. Equipped with skilled scientists, extensive experience in developing unique bioconjugation strategies for antibodies and ONs, Creative Biolabs provides high-quality AOCs using the most advanced bioconjugation chemistry for global clients.

Protein Arrays

Protein microarrays have been used in many biomedical applications including the analysis of protein-protein interactions, the detection of proteins in serum, and the study of posttranslational modifications. Specifically, antibody-based proteomics can identify and validate cancer biomarkers as well as provide a diagnostic approach for the identification of different tumor types. Moreover, antibody microarrays have been used to identify specific cancer as well as distinguish patients with cancer from healthy controls. Because antibody microarrays also can capture cells, they allow the possibility of detecting rare cells such as circulating tumor cells (CTCs).

Current Limitation and Solutions of Protein Arrays

Though there are numerous applications for antibody arrays, the construction of these protein arrays is a significantly greater challenge. The generation of antibody microarrays requires immobilization of the antibody on either hydrophobic or chemically reactive surfaces but this approach can cause denaturation and loss of activity due to immobilization of the protein in a nonproductive orientation or nonspecific binding of the protein to the surface. One approach to preserving the protein conformation is DNA directed antibody immobilization. Briefly, one can immobilize antibodies on a DNA array by first modifying the protein of interest with a single-stranded ON. This approach prevents protein denaturation and loss of binding activity associated with printing antibodies on a solid support and potentially allows for greater control of the orientation of the surface-bound antibodies.

Fig.1 Synthesis of protein array using an anti-Her2 Fab with site-specific incorporation of pAcF. (Wold, 2015)

Multiplex Assay Development

Several methods are typically used for multiplex immunoassays, which loosely fit into two categories: immobilization on a solid surface, in which the assays for each analyte are spatially separated, or immobilization on beads or particles, in which the assays for each analyte are on a different bead/particle.

Multiplex protein detection technology now takes advantage of the specific binding between two complementary strands of DNA, with one strand (analyte) for each cognate immobilized onto a solid support such as a microtiter plate. The AOCs are pooled and hybridized to their specific immobilized capture oligos in the well to create a mAb array. This approach was later expanded to generate antibody arrays for the diagnostics of antigens and whole cells on chips. This indirect immobilization of proteins and antibodies (generation of DNA arrays and their following transformation into protein arrays) has been proven to work under mild conditions, ensuring protein integrity.

What Can We Do for You?

By utilizing the site-specific conjugation between ON and antibody, Creative Biolabs has developed a DNA directed antibody microarray system that allows for the facile generation of antibody microarrays while circumventing many of the drawbacks of conventionally produced antibody arrays such as denaturation of the antibody during production, and poor shelf life. This system takes advantage of the specific binding between two complementary strands of DNA, with one strand placed at a specific location on the microtiter plate. Complementary oligos are conjugated to the user-selected antibody. The AOCs are pooled and hybridized to capture oligos in the well to create an antibody array.

The preparation of mAb arrays remained an active field of research due mainly to the virtually unlimited scope of targeted antigens and the exceptional affinities of antibodies. If you need to develop any drug bioconjugates, diagnostic bioconjugates, or research bioconjugates, Creative Biolabs is here to help you. Contact us for more information.

Reference

1. Wold, E. D.; et al. Antibody microarrays utilizing site-specific antibody-oligonucleotide conjugates. Bioconjugate chemistry. 2015, 26(5): 807-811.

For Research Use Only. NOT FOR CLINICAL USE.