Fluorescent conjugated polyfluorene with pendant lactopyranosyl ligands for studies of Ca(2+)-mediated carbohydrate-carbohydrate interaction.
A well-defined fluorescent conjugated polyfluorene with pendant lactopyranosyl ligands was easily prepared through Cu(I)-catalyzed azide/alkyne "click" ligation and Suzuki coupling polymerization. As a fluorescent multivalent model system of glycoconjugates, the polymer was first used for studies of metal ion-mediated carbohydrate-carbohydrate interaction based on fluorescence spectroscopy. A significant fluorescence quenching of the lactosyl-bearing polyfluorene was observed upon addition of calcium ion, which is attributed to the polymer aggregation derived from Ca(2+)-mediated complex formation. Dynamic light scattering can also prove Ca(2+)-induced aggregation of the polymer based on determination of the corresponding hydrodynamic diameters. The calcium-mediated lactose-lactose interaction was reversible when treated with EDTA. In control studies, Ca(2+)-induced fluorescence quenching can not be observed for cellobiosyl- or galactosyl-functionalized polymer analogues, which show that specific sugar structures are critical for carbohydrate-metal complex formation.
Chen
Qi
Q
National Center for Nanoscience and Technology, Beijing 100190, China.
Cui
Yi
Y
Zhang
Tian-Long
TL
Cao
Jie
J
Han
Bao-Hang
BH
D002118:Calcium / Q000494:pharmacology*; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D005449:Fluorenes / Q000737:chemistry*; D005453:Fluorescence; D007785:Lactose / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*
D002241:Carbohydrates; D005449:Fluorenes; D011108:Polymers; C542782:poly(9,9-di-n-octyl-2,7-fluorene); D007785:Lactose; D002118:Calcium