6533b86dfe1ef96bd12ca809

RESEARCH PRODUCT

false

John B. LloydGerhard HörpelMargaret K. PrattenHelmut Ringsdorf

subject

chemistry.chemical_classificationLiposomechemistry.chemical_compoundMembraneEthylene oxidechemistryPinocytosisPolymer chemistryCopolymerChemical modificationPolymerMicelle

description

A block copolymer (6) with both hydrophilic and hydrophobic regions was synthesized, in order to examine its interaction with model membranes and its uptake by living cells. The copolymer comprised poly(ethylene oxide) and poly(L-lysine) with 50 mol-% substitution of the e-amino groups with palmitoyl groups. To permit 125I-labelling, p-methoxyphenyl residues (1–4 mol-%) were incorporated into the block copolymer and into a poly(ethylene oxide) used for comparison. Sudan Red 7 B solubilization studies indicated that the block copolymer, but not the homopolymer, forms micelles. Differential scanning calorimetry of dipalmitoyl-phosphatidylcholine liposomes indicated that the block copolymer interacts with and probably penetrates lipid membranes. Both poly(ethylene oxide) and the block copolymer were captured by rat peritoneal macrophages in vitro, and inhibitor studies indicated that uptake of both polymers was by pinocytosis. Rates of uptake were indicative of adsorptive pinocytosis, and it is concluded that both poly(ethylene oxide) and the block copolymer present a largely hydrophilic aspect which interacts positively with the cell surface.

https://doi.org/10.1002/macp.1985.021860406