Construction and in vitro performance testing of a multi-modified hemerythrin-based nano-oxygen carrier
BACKGROUND:Molecular stability and biocompatibility of hemerythrin surpass those of human and mammalian hemoglobin,making it a potential candidate for a safer and more effective erythrocyte substitute after modification.OBJECTIVE:To prepare multi-modified hemerythrin nanoparticles,characterize them,and test their performance in vitro.METHODS:The hemerythrin of Sipunculus sphenodontus was separated and purified by tangential flow ultrafiltration.The intramolecular cross-linking was completed by genipin.The nanoparticles were encapsulated by dopamine,and passivated by polyethylene glycol to obtain multi-modified hemerythrin nanoparticles.The physicochemical properties of the nanoparticles were characterized.Hemerythrin nanoparticles,hemerythrin,and hemoglobin oxygen carrier HBOC-201 with different mass concentrations(0,0.25,0.5,1.0,and 2.0 mg/mL)were incubated with macrophages for 6 and 24 hours,and with endothelial cells for 24 hours.The cell survival rate was detected by CCK-8 assay.The levels of nitric oxide and vascular cell adhesion factor 1 in the culture medium of endothelial cells were detected by ELISA.RESULTS AND CONCLUSION:(1)Under electron microscopy,hemerythrin nanoparticles were ellipsoidal,with a dense outer membrane and a relatively uniform internal texture.The particle size was(150.12±1.67)nm;the dispersion index was 0.21±0.03;the Zeta potential was(-24.54±2.61)mV;the half-saturated oxygen partial pressure was(0.97±0.15)kPa,and the Hill coefficient was 1.49±0.16.(2)After incubation for 6 hours,within the mass concentration range of≤1.0 mg/mL,the survival rates of macrophages in the hemerythrin nanoparticle group,the hemerythrin group,and the HBOC-201 group were all above 85%.At a mass concentration of 2.0 mg/mL,only the survival rate of macrophages in the hemerythrin nanoparticle group was above 80%.After incubation for 24 hours,the survival rates of macrophages in the three groups were all lower than 80%,among which the survival rate of macrophages in the hemerythrin nanoparticle group was higher than that in the hemerythrin group and the HBOC-201 group(P<0.05).(3)With the increase of drug concentration,the survival rate of vascular endothelial cells in the three groups decreased.At 1.0 mg/mL or 2.0 mg/mL mass concentration,the survival rate of cells in the hemerythrin nanoparticle group was higher than that in the hemerythrin group and HBOC-201 group(P<0.05).At the same mass concentration,the nitric oxide level in the hemerythrin nanoparticle group was higher than that in the hemerythrin group and HBOC-201 group(P<0.05).In the range of 0.25-2.0 mg/mL mass concentration,the vascular cell adhesion factor 1 level in the hemerythrin nanoparticle group was lower than that in the hemerythrin group and HBOC-201 group(P<0.05).(4)The results showed that the hemerythrin nanoparticles modified with intramolecular cross-linking and polydopamine/polyethylene glycol had good oxygen-carrying activity in vitro,better anti-phagocytic performance,and less cytotoxicity.