pH-sensitive Oxygen Release Microspheres to Enhance Cell Survival in Ischemic Condition

Ischemic diseases such as myocardial infarction, stroke and limb ischemia are severe cardiovascular diseases with high rate of death and millions of people suffered from these diseases. Under ischemic environment, cells die due to deficient supply of nutrient and oxygen. To regenerate ischemic tissues, stem cell therapy is a promising approach because stem cells can differentiate into cells necessary for the regeneration. However, stem cell therapy has limitations. For example, few cells can survive under harsh ischemic environment. To enhance stem cells survival, implantation of oxygen release microspheres to sustained supply cells with oxygen represents an effective strategy. Previously, our laboratory has developed a series of oxygen release microspheres. While these microspheres augmented cell survival, their oxygen release kinetics is not yet ideal as the oxygen release is not responsive to local pH in tissues. In this research, we have synthesized pH-sensitive shells for tailoring oxygen release under pH condition of the ischemic tissues. We find the microspheres can release oxygen faster in specific pH condition with pH-sensitive shells. With oxygen release microspheres, cell survival was highly enhanced after incubation under ischemic condition for 14 day