Quantification of Therapeutic Antibodies Conjugated to Gold Nanoparticles

Gold nanoparticles (GNPs) are emerging as an excellent modular platform for the delivery of various antibody-based immunotherapies to solid tumors. GNPs enable the conjugation of different antibodies at high quantities on the same single particle in a defined manner, which can expand the therapeutic window and enhance the therapeutic effect. However, to promote the clinical application of such antibody-based nanomedicines and enable exact dosing, it is crucial to precisely determine the number of antibodies bound to each particle, and whether they remain active following conjugation. Here, we designed GNPs conjugated to the anti-epidermal growth factor receptor, cetuximab, and compared several prominent analysis approaches in order to determine the most precise for quantifying the bound antibodies. Moreover, we evaluated the effect of increasing the number of antibodies conjugated to a single GNP on the efficacy and toxicity of this immunotherapy.