Use of a folate-PPE conjugate to image cancer cells in vitro.
We have demonstrated synthesis and application of a water-soluble, folate-substituted poly(p-phenyleneethynylene) (PPE) as a fluorescent contrast agent to image cancer cells. This fluorescent polymer targets and images KB cancer cells in vitro with high selectivity. To deliver PPE to the cells, folate ligands have been attached to an amine-functionalized PPE via an amide coupling agent. The hydrolysis of the ester groups gave a water-soluble PPE, 5. The PPE 5 is minimally cytotoxic at concentrations of 1-10 microg/mL, which is sufficient to stain KB cancer cells efficiently. PPE 6, devoid of folate ligands, did not stain KB cells. As a low folic acid (-) receptor control group, NIH 3T3 fibroblast cells were incubated with 5 and did not show fluorescent labeling. The folate receptor-mediated endocytosis of KB cells was evidenced by laser scanning confocal microscopy and fluorescence microscopy. The photochemical stability and ability to sustain multivalency provide advantages of PPEs over other fluorescent contrast agents. Their minimal cytotoxicity makes the PPE superior to the cytotoxic CdSe quantum dots.
Kim
Ik-Bum
IB
School of Chemistry and Biochemistry, 770 State Street, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Shin
Heungsoo
H
Garcia
Andres J
AJ
Bunz
Uwe H F
UH
D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D004705:Endocytosis; D005456:Fluorescent Dyes / Q000032:analysis / Q000138:chemical synthesis / Q000378:metabolism*; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D041681:NIH 3T3 Cells; D009369:Neoplasms / Q000737:chemistry* / Q000175:diagnosis / Q000378:metabolism; D011108:Polymers / Q000032:analysis / Q000138:chemical synthesis / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism
D002352:Carrier Proteins; D005456:Fluorescent Dyes; D058973:Folate Receptors, GPI-Anchored; D011108:Polymers; D011956:Receptors, Cell Surface; C473966:poly(phenylene ethynylene); D005492:Folic Acid