Oxygen‐releasing polycaprolactone/calcium peroxide composite microspheres

Oxygen‐releasing polycaprolactone/calcium peroxide (PCL/CaO2) composite microspheres were fabricated via homogenization, electrospray with a single nozzle, and electrospray with a co‐axial nozzle, resulting in homogenized, single‐walled, and double‐walled microspheres, respectively. Scanning electron microscopy revealed that homogenized microspheres had pores, while electrosprayed microspheres did not. Alizarin Red S staining showed a core‐shell structure for double‐walled microspheres. In a hypoxia incubator, single‐walled, double‐walled, and homogenized microspheres could maintain oxygen tension in PBS at or above 10% for approximately 5, 4, and 3 days, respectively. All the PCL/CaO2 microspheres could support viability of pancreatic β‐cell line MIN6 cells in 2D cultures in a hypoxia incubator for 1 week, with the cells supported by double‐walled and homogenized microspheres exhibiting the highest and the lowest metabolic activity, respectively. For 3D MIN6 cell cultures in a hypoxia incubator, single‐walled and homogenized PCL/CaO2 microspheres led to the highest and the lowest live cell densities, respectively. Double‐walled and single‐walled microspheres provided the best support for 2D and 3D cultures, respectively, suggesting that they are suitable for different applications.