Aspects of “antigen–antibody” interaction of chicken infectious bronchitis virus determined by surface plasmon resonance

[Display omitted] •Space-size effect on IBV antigen–antibody interaction was first time demonstrated.•Surface functional coating enable reduces non-specific interaction in 2 times.•Buffer acidity change from pH7.3 to pH6.8 reduces non-specific interaction in 6 times. Authors performed investigation on “antigen–antibody” interaction of chicken infectious bronchitis coronavirus (IBV) by a method based on the surface plasmon resonance (SPR). Presence of space-size effect related to a difference between antigen and antibody particle sizes has been theoretically grounded and experimentally proven. Herewith, the difference between responses of the SPR-sensor to specific and non-specific interactions is considerably less (up to 6.3 times) than the expected one (8 – 11 times). An impact of functionalization of sensor’s sensitive element surface, as well as acidity of buffer solution on the activity of antigen–antibody interaction was studied here. The difference between sensor’s responses to specific and non-specific interactions increased two-fold from 200 to 432ang sec due to this treatment. When changing the acidity of analyzed solution from pH7.3 to pH6.8, the corresponding difference between sensor’s responses increased by 6.3 times from 194 up to 1235ang.sec. Thus, an impact of space-size effect on interaction between IBV antigen and specific antibody can be considerably (almost in 3 times) decreased by reducing the acidity of used buffer solution. The results of our investigation can be successfully applied to develop new methods for detection of pathogens and specific antibodies using SPR.