Two kinds of anti-ricin antibody and ricin interaction evaluated by biosensor based on imaging ellipsometry

In order to meet the requirements of antibody comparison and evaluation, the optimization for the surface modification, ligand immobilization, unspecific blocking and ligand-receptor interaction condition is introduced to the biosensor based on imaging ellipsometry (BIE), so that it may serve as an antibody screening platform to evaluate antibody-antigen interactions. Two kinds of anti-ricin antibody named pVHHS1 and 5S1R are immobilized in a patterned array format on the silicon surface modified with succinic anhydride, respectively, to form a sensing surface. Ricin and its similar toxin abrin as the reference in solution are delivered, respectively, on the patterned sensing surface for anti-ricin antibody and ricin interaction. The limit of detection value of ricin detected by pVHHS1 and 5S1R is obtained as 1 μg/ml and 5 ng/ml, respectively. Results show that pVHHS1 and 5S1R specifically bind with ricin but not with abrin, which is in accordance with ELISA's result.