Biosensor immunosurface engineering inspired by B-cell membrane-bound antibodies: modeling and analysis of multivalent antigen capture by immobilized antibodies

Immobilized antibodies are used by many biosensors and diagnostic tests as specific receptors for the presence of targeted substances in clinical, biological, or environmental samples. The antibodies used in these devices are the soluble form of the antibodies presented on the B-cell membrane: they have the same specificity, but they may differ from those presented on the B cell in orientation, flexibility, mobility, and support-membrane properties. These properties influence the formation of noncovalent bonds between the pathogen antigenic determinants (epitopes) and the amino acids of the antibodies. This paper extends the theoretical modeling foundation addressing multivalent antigen binding to cell surface receptors to account for local and far-field antibody surface density effects, immobilized antibodies, and the flexibility and range of motion of immobilized antibodies. An analysis of the derived model provides insight into the design of biosensor immunosurfaces to enhance pathogen capture capability.