Hemolysis assay

Rabbit whole blood was harvested in heparinized tubes, followed by centrifugation at 700 × g for 10 min to obtain RBC. The RBC pellet was washed with normal saline and diluted to 5% concentration by volume. The RBC suspension was treated with α-hemolysin (450 ng mL^-1), F-AgÅPs (2.5 ng μL^-1), α-hemolysin + F-AgÅPs, vehicle (normal saline)- or F-AgÅPs-pretreated α-hemolysin (450 ng mL^-1), an equal volume of α-hemolysin-reduced supernatant, or an equal volume of vehicle (normal saline or PBS + normal saline). RBC treated with water served as positive control and the negative control was RBC treated with PBS. After 3 h of incubation at 37 °C with gentle shaking, the suspension was photographed and then centrifuged at 700 × g for 10 min. The absorbance of free hemoglobin in the supernatant was tested by a microplate reader at 541 nm. Hemolytic rate (%) = (absorbance of treated cells - absorbance of negative control cells) / (absorbance of positive control cells - absorbance of negative control cells) × 100.