Non-ionic detergents facilitate non-specific binding of M13 bacteriophage to polystyrene surfaces.
Phage-displayed random peptide libraries are widely used for identifying peptide interactions with proteins and other substrates. Selection of peptide ligands involves iterative rounds of affinity enrichment. The binding properties of the selected phage clones are routinely tested using immunoassay after propagation to high titre in a bacterial host and precipitation using polyethylene glycol (PEG) and high salt concentration. These immunoassays can suffer from low sensitivity and high background signals. Polysorbate 20 (Tween(®) 20) is a non-ionic detergent commonly used in immunoassay washing buffers to reduce non-specific binding, and is also used as a blocking reagent. We have observed that Tween 20 enhances non-specific M13 library phage binding in a peptide-independent manner. Other non-ionic detergents were also found to promote significant, dose-dependent non-specific phage binding in ELISA. This effect was not observed for assays using phage concentrated by ultracentrifugation, suggesting that interactions occur between detergents and the PEG-precipitated phage, irrespective of the displayed peptide motif. This artefact may impact on successful affinity selection of peptides from phage-display libraries. We propose alternative methods for screening phage libraries for identifying binding interactions with target ligands.
School of Life Sciences, and Biomedical Research Unit in Gastrointestinal and Liver Diseases, Faculty of Medicine and Health Sciences, University of Nottingham, UK; Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Saudi Arabia.
Abdulrahim R
AR
Hakami
School of Life Sciences, and Biomedical Research Unit in Gastrointestinal and Liver Diseases, Faculty of Medicine and Health Sciences, University of Nottingham, UK.
Jonathan K
JK
Ball
School of Life Sciences, and Biomedical Research Unit in Gastrointestinal and Liver Diseases, Faculty of Medicine and Health Sciences, University of Nottingham, UK. Electronic address: alex.tarr@nottingham.ac.uk.
Alexander W
AW
Tarr
D000327:Adsorption; D017104:Bacteriophage M13 / Q000737:chemistry*; D003902:Detergents / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D053585:Virus Attachment
D003902:Detergents; D011137:Polystyrenes
Bacteriophage; Biopanning; ELISA; Immunoassay; Peptide library; Tween