Development of competitive ELISA for the detection of bovine serum albumin using single-chain variable fragments.

Soluble anti-bovine serum albumin (BSA) single-chain variable fragments (scFvs) were expressed in E. Coli. HB2151. The antigen-binding equilibrium dissociation constant of the scFvs was determined to be 2.9 × 10-8  M by surface plasmon resonance analysis. A competitive ELISA for the detection of BSA was developed using the antibody fragment above. The limits of detection (I10 ) and I50 were 0.002 and 0.74 μg/ml respectively, with a recovery between 87.8 and 119.2% in spiked milk samples. The assay has the potential to be used to detect concentration of BSA in milk or other matrix instead of the ELISA based on traditional antibodies.