Electrosprayed low toxicity polycaprolactone microspheres from low concentration solutions

Abstract This work describes the successful tunable production of polycaprolactone (PCL) microspheres using very low-concentration solutions. The PCL solutions (1, 3, and 5 w/v%) were prepared with different solvents (dichloromethane (DCM) and chloroform (CHL)) and electrosprayed at different distances (5, 10, and 15 cm). The solubility and viscosity of PCL solutions were in accordance with the polymer concentrations, demonstrating PCL-DCM gave a higher solubility of PCL, but PCL-CHL solutions had a higher viscosity. Optical microscopy (OM) and field emission-scanning electron microscopy (FE-SEM) revealed that the PCL-DCM preparations produced a smaller and more uniform microsphere size and pore size compared to PCL-CHL microspheres. The linear regression analysis showed that the solubility and viscosity of PCL concentration influence the size of microspheres more greatly than the pore size. The toxicity results indicated that PCL-CHL and PCL-DCM are well-tolerated by zebrafish embryos that were able to follow a normal growth pathway and can thus be deemed safe.