Ultrasensitive fluorescent responses of water-soluble, zwitterionic, boronic acid-bearing, regioregular head-to-tail polythiophene to biological species.
Water-soluble regioregular head-to-tail zwitterionic fluorescent conjugated boronic acid-bearing polythiophene (polymer 2) was prepared through a postpolymerization quaternization of a pyridine group of 3-pyridineboronic acid with bromide groups of regioregular head-to-tail poly(3-bromohexylthiophene) (polymer 1). Titration of monosaccharides, lactose, ascorbic acid, or dopamine with 0.1 M phosphate buffer (pH 7.4), containing 4.0 microM of polymer 2, results in significant concentration-dependent quenching of the polymer fluorescence. The polymer displays an optimum response to the biological species at pH 7.0. The binding constants of polymer 2 with mannose, fructose, glucose, galactose, vitamin C, dopamine, and lactose are 3.33 x 10(4), 1.13 x 10(5), 1.23 x 10(5), 1.69 x 10(5), 3.17 x 10(5), 3.27 x 10(5), and 4.60 x 10(5), respectively.
Xue
Cuihua
C
Department of Chemistry, Michigan Technological University, Townsend Drive 1400, USA.
Cai
Feifei
F
Liu
Haiying
H
D001205:Ascorbic Acid / Q000737:chemistry; D001665:Binding Sites; D015374:Biosensing Techniques / Q000379:methods*; D001897:Boronic Acids / Q000737:chemistry*; D001965:Bromides / Q000737:chemistry; D002021:Buffers; D004298:Dopamine / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007785:Lactose / Q000737:chemistry; D008956:Models, Chemical; D009005:Monosaccharides / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis*; D011725:Pyridines / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000138:chemical synthesis*; D014867:Water / Q000737:chemistry*
C521705:3-pyridineboronic acid; D001897:Boronic Acids; D001965:Bromides; D002021:Buffers; D005456:Fluorescent Dyes; D009005:Monosaccharides; D011108:Polymers; D011725:Pyridines; D013876:Thiophenes; D014867:Water; C066730:polythiophene; D007785:Lactose; D001205:Ascorbic Acid; D004298:Dopamine