Biopanning

Biopanning is an affinity selection technique which selects for peptides that bind to a given target.Ehrlich GK, Berthold W, and Bailon P. Phage display technology. Affinity selection by biopanning. Methods in molecular biology. 2000. 147:195-208 All peptide sequences obtained from biopanning using combinatorial peptide libraries have been stored in a special freely available database named [http://i.uestc.edu.cn/bdb BDB].{{Cite journal|last=He|first=Bifang|last2=Chai|first2=Guoshi|last3=Duan|first3=Yaocong|last4=Yan|first4=Zhiqiang|last5=Qiu|first5=Liuyang|last6=Zhang|first6=Huixiong|last7=Liu|first7=Zechun|last8=He|first8=Qiang|last9=Han|first9=Ke|date=2016-01-04|title=BDB: biopanning data bank|journal=Nucleic Acids Research|volume=44|issue=D1|pages=D1127–1132|doi=10.1093/nar/gkv1100|issn=1362-4962|pmc=4702802|pmid=26503249}}{{cite journal|last=Huang|first=J|author2=Ru, B|author3=Zhu, P|author4=Nie, F|author5=Yang, J|author6=Wang, X|author7=Dai, P|author8=Lin, H|author9=Guo, FB|author10=Rao, N|title=MimoDB 2.0: a mimotope database and beyond.|journal=Nucleic Acids Research|date=Nov 3, 2011|pmid=22053087|doi=10.1093/nar/gkr922|volume=40|issue=1|pages=D271–7|pmc=3245166}} This technique is often used for the selection of antibodies too.

Biopanning involves 4 major steps for peptide selection.Mandecki W, Chen YC, and Grihalde N. A Mathematical Model for Biopanning (Affinity Selection) Using Peptide Libraries on Filamentous Phage. Journal of theoretical biology. 1995. 176:523-530 The first step is to have phage display libraries prepared. This involves inserting foreign desired gene segments into a region of the bacteriophage genome, so that the peptide product will be displayed on the surface of the bacteriophage virion. The most often used are genes pIII or pVIII of bacteriophage M13.Smith GP, and Scott JK. Libraries of peptides and proteins displayed on filamentous phage. Methods in Enzymology. 1993. 217:228-257

The next step is the capturing step. It involves conjugating the phage library to the desired target. This procedure is termed panning. It utilizes the binding interactions so that only specific peptides presented by bacteriophage are bound to the target. For example, selecting antibody presented by bacteriophage with coated antigen in microtiter plates.

The washing step comes after the capturing step to wash away the unbound phages from solid surface. Only the bound phages with strong affinity are kept. The final step involves the elution step where the bound phages are eluted through changing of pH or other environment conditions.

The end result is the peptides produced by bacteriophage are specific. The resulting filamentous phages can infect gram-negative bacteria once again to produce phage libraries. The cycle can occur many times resulting with strong affinity binding peptides to the target.