Phylogenic tree of peptide targeting candidates using acid elution of partially solubilized matrix sonicated samples. Peptide sequences were obtained after the third round of screening using (A) the IT6 protocol, which biopanned using the PHD-C7C library or (B) the IT7 protocol, which used the PHD12 library as starting material. In both instances, the phage were recovered from the acid eluates of washed sonicated samples. Sequences were analyzed for structural relatedness using MacVector sequence analysis software. Library collapse was reflected by an increased recovery of 300-fold in IT7 over the three rounds of biopanning.