Covalent binding of poly(ethylene glycol) (PEG) to the surface of red blood cells inhibits aggregation and reduces low shear blood viscosity.

A simple method to coat human red blood cells (RBC) with PEG is described. Using a reactive derivative, monomethoxy-PEG (mPEG) was covalently attached to the surface of RBC in aqueous media under mild conditions. The PEG coating dramatically reduced aggregation and low shear viscosity of RBC resuspended in autologous plasma, and inhibited RBC agglutination by blood group-specific antibodies. Morphology and deformability of the PEG-treated cells were unaltered. The PEG coating of the RBC surface may be of significant benefit in the treatment of a variety of diseases characterized by vasoocclusion or impaired blood flow, e.g., myocardial infarction, sickle cell disease.