Nucleotide adsorption–desorption behaviour of boronic acid functionalized uniform-porous particles

In this study, nucleotide adsorption–desorption behaviour of boronic acid-carrying uniform, porous particles was investigated. The particles were produced by a “multi-step microsuspension polymerization” in the form of poly(styrene–vinylphenyl boronic acid–divinylbenzene) terpolymer. In the first step of the production method, uniform polystyrene latex particles (6.2 μm in size) were obtained by dispersion polymerization. These particles were first swollen by a low molecular mass organic agent (i.e. dibutylphthalate, DBP) and then by a monomer mixture including styrene (S), 4-vinylphenyl boronic acid (VPBA) and divinylbenzene (DVB). The particle uniformity was protected in both swelling stages by adjusting DBP/polystyrene latex and monomer mixture/polystyrene latex ratios. Polymerization of the monomer mixture in the swollen seed particles provided boronic acid-carrying uniform, porous particles 11–12 μm in size. To have uniform particles with different porosities and boronic acid contents, the feed concentration of boronic acid-carrying monomer and the monomer/seed latex ratio were changed. The particles were tried as sorbent for the adsorption of a model nucleotide (i.e., β-nicotinamide adenine dinucleotide, β-NAD). In the β-NAD adsorption experiments, the maximum equilibrium adsorption was obtained at pH 8.5 which was very close to pKa of boronic acid. The incorporation of boronic acid functionality provided a significant increase in the β-NAD adsorption. In contrast to plain poly(styrene-co-divinylbenzene) particles, four-fold higher β-NAD adsorption was obtained with the boronic acid functionalized particles. β-NAD was desorbed from the particles with the yields higher than 90% by weight.