Method Better Pins Down Antibodies

A new immobilization strategy attaches antibodies to surfaces in an oriented fashion without blocking or altering antigen binding sites, according to scientists at the University of Notre Dame (Langmuir, DOI: 10.1021/la301887s). Standard methods for immobilizing antibodies can result in randomly oriented antibodies, many of which are in inactive forms. In the new method, antibodies are uniformly oriented on the surface and their antigen binding site remains unaltered. Başar Bilgiçer and coworkers immobilized antibodies on detector surfaces using a photochemical method in which indole-3-butyric acid conjugated to the detector surface serves as a cross-link to the antibody’s nucleotide binding site, a conserved region found in the variable domain of all antibody classes. Upon exposure to UV light, aromatic side chains in the binding site form radicals that covalently bond with indole-3-butyric acid. Immunoassays performed with antibodies immobilized in this way were more efficient and more sensitive than assays with antibodies immobilized by physical adsorption or lysine conjugation. The immobilization strategy did not, however, decrease the limit of detection, the researchers note.