Selection Of Peptides By Phage Display For Cancer Cell Recognition

Phage display technology is a well-developed biotechnology with powerful capabilities to quickly acquire peptides or proteins for variety of targets.Because of the advantages of peptide molecules,such as small molecular weight,easy to synthesis and modification,low biological immunogenicity,peptide has been widely used in biomedical fields as a biorecognition molecule.Nowadays cancer has caused widespread concern,tumor biomarkers which are closely related to the occurrence of tumors are often used in the diagnosis,monitoring,and prognosis of cancer.Thus it is of great significance to screen small peptide molecules with specific binding ability for biomarkers.Generally,by fixing the target on a solid-phase and after several rounds of panning,the desired phage clone can be obtained by phage display technology.Although it is an effective method for screening out the peptide with specific affinity,there are still some problem unsolved,such as the selection bias,cross-contamination easily and tedious selection procedures,etc.Therefore,developing a fast,efficient and simple screening platform is of great significance.This study aims to establish a new method for peptide screening and put the obtained peptides into application.By combining phage display with microfluidic technology,a rapid,efficient,high-throughput and automated peptide screening technology has been established,and the peptides was successfully applied to the identification of tumor cells.This work mainly contains two parts as following:(1)Using traditional phage display technology to screen tumor marker specific binding peptides.Small peptide molecules with specific binding capacity for the proteins CD71 and c-Met were obtained respectively,then their specificity and ability were verified.(2)Taking advantage of microfluidic chip which with less reagent consumption,high flux,and easy integration,a new screening method based on droplet microfluidic and phage display technology was established.Using the spiral chip for droplet generation,pre-enriched phage library and CD71 coated beads were enveloped in droplets in one-to-one manner,and the monodispersed phage in droplet proliferated by infecting host bacteria to amplify the signal.The phage clone displaying peptide with the CD71 recognizing ability will binding to the beads,after demulsification and phage nucleic staining,the monoclonal can be picked out under the fluorescence microscop without ELISA verification.This novel screening method reduced the risk of contamination,simplified screening procedure and improved the screening efficiency.