Particle Number particles per mg serum protein equals the ratio in the in vivo experiment (NP/SPiv) Aggregate size (Rh) Number particles per mg serum protein in undiluted human serum (NP/SPconc) Aggregate size (Rh) PS-LUT 8.5·1010 200 nm 8.5·109 200 nm PS-LUT-COOH 2·1012 No aggregates 1.7·1011 250 nm PS-LUT-NH2 8.5·1010 No aggregates 8.5·109 No aggregates PS-SDS 4·1010 2 µm 3.3·108 Macroscopic precipitation

Table 4: Aggregation behavior of all investigated particles in the respective serum concentrations. Except for particle PS-LUT-COOH that shows only aggregation in the undiluted serum solution, the aggregation of the investigated particles does not depend on serum concentration.