title: Targeting of embryonic stem cells by peptide-conjugated quantum dots.
abstract: BACKGROUND
  Targeting stem cells holds great potential for studying the embryonic stem cell and development of stem cell-based regenerative medicine. Previous studies demonstrated that nanoparticles can serve as a robust platform for gene delivery, non-invasive cell imaging, and manipulation of stem cell differentiation. However specific targeting of embryonic stem cells by peptide-linked nanoparticles has not been reported.
  
  
  RESULTS
  Here, we developed a method for screening peptides that specifically recognize rhesus macaque embryonic stem cells by phage display and used the peptides to facilitate quantum dot targeting of embryonic stem cells. Through a phage display screen, we found phages that displayed an APWHLSSQYSRT peptide showed high affinity and specificity to undifferentiated primate embryonic stem cells in an enzyme-linked immunoabsorbent assay. These results were subsequently confirmed by immunofluorescence microscopy. Additionally, this binding could be completed by the chemically synthesized APWHLSSQYSRT peptide, indicating that the binding capability was specific and conferred by the peptide sequence. Through the ligation of the peptide to CdSe-ZnS core-shell nanocrystals, we were able to, for the first time, target embryonic stem cells through peptide-conjugated quantum dots.
  
  
  CONCLUSIONS
  These data demonstrate that our established method of screening for embryonic stem cell specific binding peptides by phage display is feasible. Moreover, the peptide-conjugated quantum dots may be applicable for embryonic stem cell study and utilization.
authors: Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China.
authors: Shuai
authors: S
authors: Lu
authors: Xing
authors: X
authors: Xu
authors: Wenxiu
authors: W
authors: Zhao
authors: Weiwei
authors: W
authors: Wu
authors: Hang
authors: H
authors: Yuan
authors: Huaibin
authors: H
authors: Shen
authors: Changhua
authors: C
authors: Zhou
authors: Lin Song
authors: LS
authors: Li
authors: Lan
authors: L
authors: Ma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D002454:Cell Differentiation; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D008856:Microscopy, Fluorescence; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism*; D019151:Peptide Library; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D013379:Substrate Specificity; D013440:Sulfides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D009842:Oligopeptides; D019151:Peptide Library; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide