Effects of Polyols, Saccharides, and Glycoproteins on Thermoprecipitation of Phenylboronate-Containing Copolymers

Abstract

The copolymer of 3-(acrylamido)phenylboronic acid and N-isopropylacrylamide (82:18, Mn = 47000 g/mol) was prepared by free radical polymerization. The copolymer showed typical thermoprecipitation behavior in aqueous solutions; its phase transition temperature (TP) was 26.5 +/- 0.2 degrees C in 0.1 M glycine-NaOH buffer containing 0.1 M NaCl, pH 9.2. Due to specific complex formation of the pendant boronates with sugars, TP was strongly affected by the type of sugar and its concentration at pH 9.2. Fructose, lactulose, and glucose caused the largest increase in TP (up to 4 degrees C) at 0.56 mM concentration, attributed to the high binding affinity of the sugars to borate and phenylboronate. Among the sugars typical of nonreducing ends of oligosaccharides, N-acetylneuraminic acid had the strongest effect on TP (ca. 2 degrees C at 0.56 mM concentration and pH 9.2), while the effects of other sugars are well expressed at the higher concentrations (16 and 80 mM) and decreased in the order xylose approximately galactose >or= N-acetyllactosamine >or= mannose approximately fucose >> N-acetylglucosamine. The effect exerted on the phase transition by glycoproteins was the strongest with mucin from porcine stomach and decreased in the series mucin > horseradish peroxidase > human gamma-globulin at pH 9.2. As a first approximation, the weight percentage and/or the number of oligosaccharides in glycoproteins determined the character of their interaction with the pendant phenylboronates and, therefore, the effect on the copolymer phase transition.

Carbohydrate-actuated nanofluidic diode: switchable current rectification in a nanopipette

“…Presumably, this occurs when a significant portion of the polymer becomes zwitterionic, increasing the hydrophobicity of the molecule. 50,51 This precipitation point was highly reproducible (< 3% RSD for multiple trials), and at pH 7.8 is consistent with the pK a of phenylboronic acid in solution. 52 This precipitation point is modulated in the presence of 20 mM monosaccharides (see Fig.…”

Carbohydrate recognition by boronolectins, small molecules, and lectins

“…There have been many other applications of boronic acid-based sensors for glycoproteins combined with chromatography,283 polymers,284,285 and electrochemistry, which will be discussed in the later sections 279,286,287…”

Responsive Boronic Acid-Decorated (Co)polymers: From Glucose Sensors to Autonomous Drug Delivery

“…A copolymer of NIPAAm/NIPMAAm with DDOPBA was demonstrated to show glucose controlled lower critical solution temperature (LCST) behavior under physiological conditions [23]. A more common combination of NIPAAm with m APBA showed remarkable control over the LCST transition of the formed copolymer using pH and d -Glu but also by variation of the concentration of RNA [24], d -fructose, ascorbic acid, nucleotides and other saccharide containing biomolecules including polyols and glycoproteins [25,26,27]. …”