In vitro blood compatibility assay

First, red blood cells were extracted from 6-week-old rats and centrifuged at 3,500 rpm for 10 min to remove supernatant. Then, PBS was added for washing and the concentration of red blood cells was adjusted to 16%. The m-CuS-PEG was diluted with PBS for 5, 10, 50, 100, 200, 400, 800 μg/ml solution. 100 μl red blood cell solution was added with 1 ml m-CuS-PEG solution of different concentrations, and pure water was added as positive control and PBS as negative control. After incubation for 8 h, absorbance was measured at 540 nm. The hemolysis rate was calculated by the following:

Note that Asamples was the absorbance of samples incubated with nanoparticles measured at different time intervals. Apostive was the absorbance of samples incubated with pure water and Anegative was the absorbance of samples incubated with PBS.