Partition of Linear and Cyclic Oligosaccharides in Aqueous Two-Phase Systems

Abstract

In aqueous two-phase systems, such as PEO/pullulan and PEO/dextran systems, partitioning of linear and cyclic oligosaccharides was investigated. The α 1-4 linked linear oligosaccharides, such as glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were partitioned more to the bottom polysaccharide-rich phase than to the top PEO-rich phase. The partition coefficient, K (the ratio of the concentration of oligosaccharide in the polysaccharide-rich phase to that in the PEO-rich phase), increased with an increase in the glucose units in the oligosaccharide. The extent of the partition of the oligosaccharides was affected by the structure of polysaccharide employed in the two-phase system. Compared with the PEO/pullulan system, the PEO/dextran system showed a higher partition selectivity for the linear oligosaccharides. The structural characteristics of dextran with branched skeleton should be more suitable for multipoint interactions with the linear oligosaccharides, however, more cyclodextrin (CD) was always found in the PEO phase than in the polysaccharide phase. The partition coefficient sequence of the cyclodextrins to the PEO-rich top phase was β-CD > α-CD > γ-CD. The partitioning of more β-CD to the PEO phase may be due to better incorporation of the PEO chain into the β-CD cavity.

A Hybrid Hydrogel Biomaterial by Nanogel Engineering: Bottom‐Up Design with Nanogel and Liposome Building Blocks to Develop a Multidrug Delivery System

“…[ 41 ] Mason proposed that the MSD, [ Δ r 2 ( t )], could be converted into the complex modulus, G * ( ω ), by Fourier transformation (see Supporting Information). G ′ ( ω ) (storage modulus) and G ″ ( ω ) (loss modulus) can be calculated as the real and imaginary parts of G * ( ω ).…”

“…In our previous report, the coat surrounding the outermost surface of a liposomal membrane with nanogels was evaluated using fl uorescence depolarization, gel chromatography, and DLS. [ 41 ] Confocal laser microscopy also revealed that the outermost surface of a giant liposome was fully coated with the nanogels. [ 42 ] The binding constant increased with increases in the substitution degree of the cholesteryl moiety and the molecular weight of the pullulan derivatives used, while the maximum polysaccharide content of the coat was hardly changed.…”

“…[ 41 ] In this study, we determined the extent of the surface coverage of the CHPOA nanogel coat on liposomes by sucrose-gradient fl otation. A rhodamine-labeled CHP nanogel and NBD-labeled DMPC liposomes were used in this experiment.…”

Partitioning of Ganglioside-Reconstituted Liposomes in Aqueous Two-Phase Systems

“…The system containing 150 mM sodium chloride, which is comparable to physiological saline, does not provide any electrostatic potential differences [12][13][14][15][16]26,27]. Reitherman et al [20] and Zaslavsky et al [21] reported that the addition of 150 mM sodium chloride to the PEO/ dextran system in 10 mM sodium phosphate decreased the electrostatic potential difference virtually to zero.…”

“…After the liposomal lipid concentration was adjusted to 3.0 Â 10 À4 M, the suspension was filtered through a Millipore filter (pore size, 0.45 mm) prior to the dynamic light scattering (DLS) determination to remove any dust. Both the diameter and the size distribution of the liposomes were determined by dynamic light-scattering on a DLS-700 instrument (Photal Otsuka Electronics, Hirakata, Japan) [27]. The mean diameter of the ganglioside-reconstituted liposomes so obtained was approximately 125-5 nm, and the size distribution was rather monodisperse.…”