Polyvalent choline phosphate as a universal biomembrane adhesive

Phospholipids in the cell membranes of all eukaryotic cells contain phosphatidyl choline (PC) as the headgroup. Here we show that hyperbranched polyglycerols (HPGs) decorated with the ’PC-inverse’ choline phosphate (CP) in a polyvalent fashion can electrostatically bind to a variety of cell membranes and to PC-containing liposomes, the binding strength depending on the number density of CP groups per macromolecule. We also show that HPG–CPs can cause cells to adhere with varying affinity to other cells, and that binding can be reversed by subsequent exposure to low molecular weight HPGs carrying small numbers of PCs. Moreover, PC-rich membranes adsorb and rapidly internalize fluorescent HPG–CP but not HPG–PC molecules, which suggests that HPG–CPs could be used as drug-delivery agents. CP-decorated polymers should find broad use, for instance as tissue sealants and in the self-assembly of lipid nanostructures. The headgroup of phospholipids in eukaryotic cell membranes contains phosphatidyl choline (PC). Now, branched polyglycerols decorated with the 'PC-inverse' choline phosphate (CP) are shown to behave as 'universal' biomembrane adhesives, binding electrostatically to cell membranes and to PC-containing liposomes. Binding can be reversed by exposure to PC-containing polymers. These adhesives may find use as tissue sealants and as drug-delivery vehicles.