Polyglycidols are flexible hydrophilic polyethers that are potentially biocompatible polymers based on their similarities to the well-studied poly(ethyleneglycol). Polyglycidols can be prepared as branched or linear polymers by suitable synthetic methods. Biocompatibility testing of these polymers conducted in vitro as well as in vivo are reported here. The in vitro studies included hemocompatibility testing for effects on coagulation (PT and APTT), complement activation, red blood cell aggregation, and whole blood viscosity measurements. In vitro cytotoxicity experiments were also conducted. The results were compared with some of the common biocompatible polymers already in human use. Results from these studies show that polyglycidols are highly biocompatible. Hyperbranched polyglycidols were found to be well tolerated by mice even when injected in high doses.

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.

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Three hydrolytically stable polyethyleneglycol (PEG)-based N-substituted acrylamide macromonomers, methoxypolyethyleneglycol (350) acrylamide (MPEG350Am) methoxypolyethyleneglycol (750) acrylamide(MPEG750Am) and methoxypolyethyleneglycol (2000)acrylamide (MPEG2000Am) with increasing PEG chain length were synthesized. Surface-initiated aqueous atom transfer radical polymerization (ATRP) using CuCl/1,1,4,7,10,10-hexamethyl triethylene tetramine (HMTETA) catalyst was utilized to generate dense polymer brushes from these monomers via an ester linker group on the surface of model polystyrene (PS) particles. The molecular weight, hydrodynamic thickness, and graft densities of the grafted polymer layers were controlled by changing the reaction parameters of monomer concentration, addition of Cu(II)Cl2, and sodium chloride. The graft densities of surface-grafted brushes decreased with increasing PEG macromonomer chain length, 350 > 750 >> 2000, under similar experimental conditions. The molecular weight of grafts increased with increase in monomer concentration, and only selected conditions produced narrow distributed polymer chains. The molecular weight of grafted polymer chains differs significantly to those formed in solution. The hydrodynamic thicknesses of the grafted polymer layers were fitted to the Daoud and Cotton model (DCM) for brush height on spherical surfaces. The results show that the size of the pendent groups on the polymer chains has a profound effect on the hydrodynamic thickness of the brush for a given degree of polymerization. The new PEG-based surfaces show good protection against nonspecific protein adsorption from blood plasma compared to the bare surface. Protein adsorption decreased with increasing surface density of grafted polymer chains. Poly(MPEG750Am) brushes were more effective in preventing protein adsorption than poly(MPEG350Am) even at low graft densities, presumably due to the increase in PEG content in the grafted layer.

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