glass beads to dislodge the bacteria serially diluted and viable plate counts performed in addition the films were removed and vortexed in sterile saline to dislodge bacteria adherent to the films and counts were performed on these as well blood was obtained from healthy human donors red cells were isolated from whole heparinized blood by centrifugation and removal of platelet rich plasma the red cells were washed three times with phosphate buffered saline pbs 145 mm nacl 10 mm na 2 po 4 and made up as a 10 v v solution in pbs copolymer samples were placed in 1 5 ml eppendorf centrifuge tubes 50 mg per tube and equilibrated in 400 microlitres pbs at 37 u00b0 c for 1 h then 100 microlitres of the 10 red cell suspension was added to make a final red cell concentration of 2 the copolymer samples were incubated in the red cell suspension for 1 h at 37 u00b0 c after the incubation time was complete the red cells were centrifuged out of solution and 100 microlitres of supernatant from each sample was transferred to a 96 well plate the absorbance of each solution was measured in a plate reader at 540 nm and compared to the positive control 0 1 triton x.