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Storage lesions in red blood cells (RBCs) hinder efficient circulation and tissue oxygenation. The absence of flow mechanics and gas exchange may contribute to this problem. To test if in vitro compensation of flow mechanics and gas exchange helps RBC recovery, three-dimensional polydimethylsiloxane (PDMS) porous structures were fabricated with a sugar mould, simulating lung alveoli. RBC suspensions were passed through the porous structure cyclically, simulating in vivo blood circulation. Acid-base indices, partial gas pressures, ions, glucose and RBC indices were analyzed. An atomic force microscope was used to investigate local mechanical properties of intact RBCs. RBCs suspensions that passed through the porous structures had a higher pH and oxygen partial pressure, and a lower potassium concentration and carbon dioxide partial pressure. Meantime they had better biochemical properties relative to static samples, namely, they exhibited a more homogenous distribution of Young's Modulus. RBCs that passed through a PDMS porous structure were healthier than static ones, giving hints to prevent RBC storage lesions. [ABSTRACT FROM AUTHOR]

Oxidative toxicity has impeded the development of haemoglobin-based oxygen carriers (HBOCs) by causing methaemoglobin (MetHb) formation and inducing oxidative stress. In our previous work, polydopamine-coated haemoglobin (Hb-PDA) nanoparticles have been designed and synthesized with the capacity to reduce oxidative toxicity. In this investigation, the mass ratio of dopamine (DA) to haemoglobin (Hb) and the pH value are found to be the primary factors that influence preparation of Hb-PDA nanoparticles. X-ray photoelectron spectroscopy showed that the catechol groups of DA play a crucial role in the modification of Hb surface. Hb-PDA nanoparticles were found to exhibit oxidative protection from hydrogen peroxide (H2O2) and the change of mitochondrial membrane potential showed that the Hb-PDA nanoparticles reduced H2O2-induced apoptosis. It is demonstrated that modification of PDA could maintain the oxygen-release capacity of Hb. These findings confirm that Hb-PDA nanoparticles possess restrained oxidative toxicity and preserve oxygen-release capacity. [ABSTRACT FROM AUTHOR]