The application of k-ELISA for measuring phage concentration was performed by precoating wells using 0.25 μg/ml of TnT (or BSA in negative control). The next steps regarding washing were performed in the same way as described above, despite that for blocking 0.01% myoglobin was applied and phages (concentrations range: 0, 2x10 9 , 4x10 9 , 6x10 9 , 8x10 9 pfu/ml) and HRPconj. Antibody solutions were added in amounts of 50 μl. Myoglobin was chosen as a blocking agent due to its small size (approximately 17 kDa), globular shape and low price. BSA as a widely used blocking agent was avoided because it was present in all panning rounds, and peptides were suspected of exhibiting affinity to BSA. The signal was recorded by reading absorbance at 370 nm in a kinetic experiment every 70 s for 10 minutes.