@article {3838, title = {Poly(ethylene glycol) amphiphile adsorption and liposome partition}, journal = {Journal of Chromatography B-Biomedical Applications}, volume = {680}, number = {1-2}, year = {1996}, note = {ISI Document Delivery No.: UQ821Times Cited: 4Cited Reference Count: 649th International Conference on Partitioning in Aqueous 2-Phase Systems - Advances in the Use of Polymers in Cell Biology, Biotechnology and Environmental SciencesJUN 04-09, 1995ZARAGOZA, SPAIN}, month = {May}, pages = {145-155}, type = {Proceedings Paper}, abstract = {Surface localized poly(ethylene glycol) (PEG) amphiphiles of type C-16:0-EO(151) and C-18:2-EO(1.51) were studied via ellipsometry at macroscopic, hat methylated silica (MeSi), phosphatidic acid (PA), and phosphatidylcholine (PC) surfaces. At these surfaces the amphiphiles adsorb similarly, in a non-cooperative manner, achieving a plateau (approximate to 0.1 PEG chains/nm(2)) well below amphiphile critical micelle concentration (CMC). The resultant PEG-enriched layers were 10-15 nm thick, with a polymer concentration (approximate to 0.07 g/cm(3)) greater than the PEG-enriched phase of many dextran, PEG aqueous two-phase systems. PEG-amphiphile adsorption (mg/m(2)) at hydrophobic and phospholipid flat surfaces correlated with changes in the partition (log K) of PC liposomes in such two-phase systems. PEG-amphiphile adsorption at macroscopic surfaces appears to represent a balance between hydrophobic attraction and repulsive intra-chain interactions which promote chain elongation normal to the surface.}, keywords = {ADSORPTION, AQUEOUS 2-PHASE SYSTEMS, BEHAVIOR, CELL-SEPARATION, critical micelle concentration, ellipsometry, HYDROPHOBIC AFFINITY PARTITION, LIPOSOMES, partitioning, PHASE SYSTEMS, poly(ethylene glycol) (PEG), polymer, PROTEINS, SURFACE-PROPERTIES, WATER-INTERFACE}, isbn = {0378-4347}, url = {://A1996UQ82100016}, author = {VanAlstine, J. M. and Malmsten, M. and Brooks, D. E.} }