Biomedical subjects

D R Skuse

Publications and source records attributed to D R Skuse.

3 recordsLinked to original sources

PubMed1992

Hydroxypropyl cellulose/poly(ethylene glycol)-co-poly(propylene glycol) aqueous two-phase systems: system characterization and partition of cells and proteins.

Novel aqueous polymeric two-phase systems are described. These systems are formed by mixing hydroxypropyl cellulose (molecular mass 100,000, trade name Klucel L) with poly(ethylene glycol)-co-poly(propylene glycol) copolymer [molecular mass 6,500, poly(propylene glycol) content 50% w/w, trade name Pluronic P105], in a saline buffer. The phase diagram was measured and the interfacial tensions, phase separation times, and lower phase viscosities of three phase systems having constant Pluronic P105 concentration but varying in Klucel L concentration were determined. The partition behavior of a representative cell, bacterium, and protein and the affinity ligand-mediated alteration in the partition behavior of a protein from a yeast extract protein mixture were also characterized. The results suggest that Klucel L/Pluronic P105 phase systems may be cost-effective substitutes for, or complements to, existing aqueous polymeric phase systems. The physical characterization and representative partition data reported here should facilitate application of these new systems.

Cell Separation↗

PubMed1988

Column-based separation of erythrocytes using aqueous polymeric two-phase systems.

Cell separation using aqueous polymeric two-phase systems is well established. For separations of cells having similar partition coefficients a multi-step counter-current distribution procedure has been used. As an alternative strategy, we have developed a column-based technique in which the dextran-rich phase of a dextran-polyethylene glycol (PEG) phase system is immobilized onto derivatized chromatography beads. The PEG-rich phase is used as the eluent. A separation of erythrocytes from different species utilizing an affinity ligand was performed. The following behaviour was observed: (i) no elution occurs below a critical affinity ligand concentration; (ii) cell recovery is proportional to affinity ligand concentration; (iii) elution volume is independent of affinity ligand concentration. The above suggest that no multi-step partitioning occurs. However, the separation achieved is considerably better than in a corresponding single-tube separation. A 1:1 mixture of dog and human erythrocytes was separated to a purity of greater than 98% using the column-based technique. The corresponding optimized single-tube separation gave a maximum purity of 84%.

Animals↗

PubMed1988

Column chromatographic separation of cells using aqueous polymeric two-phase systems.

Cell separation using aqueous polymeric two-phase systems is well established. For separations of cells having similar partition coefficients a multistep countercurrent distribution procedure has to be used. However, its operation is limited by time and apparatus constraints. As an alternative strategy we have developed a chromatographic technique in which the dextran-rich phase of a dextran/polyethylene glycol (PEG) phase system is immobilized onto derivatized agarose beads. The PEG-rich phase is used as the eluent. Inclusion of PEG-fatty acid affinity ligand gradients into the eluent produces separations of mammalian erythrocytes based on the differential interaction between the fatty acid and the erythrocyte membranes. A model separation of dog and human erythrocytes has been carried out.

Cell Separation↗