PHAGOCYTIC UPTAKE BY MOUSE PERITONEAL-MACROPHAGES OF MICROSPHERES COATED WITH PHOSPHOCHOLINE OR POLYETHYLENE-GLYCOL PHOSPHATE-DERIVED PERFLUOROALKYLATED SURFACTANTS

A series of perfluoroalkylated amphiphiles derived from phosphocholine (PC) and polyethylene glycol (PEG) phosphates has been studied and co mpared to hydrocarbon analogs with respect to their ability to modify the in vitro protein adsorption, and phagocytic uptake by mouse perito neal macrophages of polystyrene microspheres coated with these surfact ants. A significant correlation between protein adsorption and phagocy tosis was seen. Within the PC-derived amphiphiles investigated, those with the shorter C2 and C5 spacers between the fluorinated tail and th e phosphocholine group, F8C2PC and F8C5PC, caused significantly lower protein adsorption and a decrease of phagocytic uptake of the microsph eres in serum vs a buffer. Phagocytic uptake is then comparable to tha t observed when pegylated surfactants are used as the coating material . These effects were no longer seen when the spacer was longer, as in F8C11PC, with the non-fluorinated analogues C10PC and C15PC, or when o ne methyl group was replaced by an ethyl group in the phosphocholine p olar head. The beneficial impact of the fluorinated tail thus appear t o be related to its distance from the surfactant film's external surfa ce and/or to the lipophobic character of the surfactant. Without serum present phagocytic uptake was lower for the fluorinated surfactants w ith hydrophilic PEG phosphate head-groups, F8C5PPEG 2000 and F8C5P[PEG 750]2, than for the PC derivatives, although it was significantly gre ater than with Pluronic F-68 or DSPE-PEG 5000. Phagocytosis was, howev er, not reduced in the presence of serum and the difference between th ese surfactants and the fluorinated PC derivatives was no longer appre ciable.