One-Step Identification of Antibody Degradation Pathways Using Fluorescence Signatures Generated by Cross-Reactive DNA-Based Arrays

Therapeutic antibodies are prone to degradation via a variety of pathways during each stage of the manufacturing process. Hence, a low-cost, rapid, and broadly applicable tool that is able to identify when and how antibodies degrade would be highly desirable to control the quality of therapeutic antibody products. With this goal in mind, we have developed signature-based sensing system to discriminate differently degraded therapeutic antibodies. The use of arrays consisting of conjugates between nanographene oxide and fluorophore-modified single-stranded DNAs under acidic pH conditions generated unique fluorescence signatures for each state of the antibodies. Multivariate analyses of the thus obtained signatures allowed identifying (i) common features of native, denatured, and visibly aggregated antibodies, (ii) complicated degradation pathways of therapeutic omalizumab upon time-course heat-treatment, and (iii) the individual compositions of differently degraded omalizumab mixtures. As the signature-based sensing has the potential to identify a broad range of degraded antibodies formed by different kinds of realistic stress types, this system may serve as the basis for high-throughput assays for the screening of antibody manufacturing processes.