Microfluidic synthesis of PLGA/carbon quantum dot microspheres for vascular endothelial growth factor delivery

In this study, vascular endothelial growth factor (VEGF) loaded poly(d,l-lactide-co-glycolide) (PLGA) - carbon quantum dot microspheres were produced using microfluidic platforms. The microcapsules were fabricated in flow-focusing geometry with a biphasic flow to generate solid/oil/water (s-o-w) droplets. To avoid any damage to protein functional and structural stability during the encapsulation process, the VEGF was PEGylated. The produced microspheres were intact and highly monodisperse in size (CV < 5%). Furthermore, microspheres in a size range of 16-36 µm were achieved by adjusting the flow ratio parameter. The encapsulation efficiency, release profile, and bioactivity of the produced microparticles were also studied. The loading efficiency of PEGylated VEGF in the microparticles was varied from 51-69% and more than 90% of PEGylated VEGF was released within 28 days. Furthermore, the release of VEGF was indirectly monitored by carbon quantum dots. The present monodisperse and controllable VEGF loaded microspheres with reproducible manner could be widely used in tissue engineering and therapeutic applications.