Verification of a specific reaction between an airborne antigen and an immobilized antibody at a gas-solid interface.

With a specific and strong molecular-recognition capability cultivated in humoral acquired immunity, an antibody has been extensively utilized in various applications, such as diagnostics and therapy. However, so far most of its uses have been limited to be in the liquid phase. In view of its potential uses, such as a gas-phase biosensor or a high-performance air filter, we have tried to verify a previously undescribed binding reaction between protein antigens and corresponding antibodies immobilized on a solid surface by using fluorescence resonance energy transfer between the two. Our data showed that the antibody on a solid surface specifically reacted with a protein antigen supplied from the gas phase under the normal ambient condition. Also discovered was that the reaction occurred even faster than that in the liquid phase under several assay conditions.