An Efficient Strategy for Fabricating and Controlling the Morphology of Hollow Poly(p-dioxanone) Microspheres Using an O/W Emulsions Solvent Evaporation Method

Hollow microspheres of biodegradable polyester polylactic-glycolic acid copolymer (PLGA) and polycaprolactone (PCL) materials have broad application prospects in the field of biomedicine and have attracted wide attention in the material industry. However, the production of poly(p-dioxanone) (PPDO) hollow microspheres with simple and low cost has not been confirmed. Here, we propose a modified emulsion solvent evaporation method to prepare PPDO hollow microspheres. Specifically, PPDO is dissolved in dichloromethane (DCM) under heating conditions, in which DCM acts as a solvent and porogen during the process. The effects of PPDO molecular weight and concentration, temperature, and oil phase composition on the morphology of microspheres were systematically investigated by scanning electron microscope (SEM). The results show that 3 w/v% PPDO at 28 °C can develop the hollow morphology of PPDO. After the introduction of ethanol (EtOH) or ethyl acetate (EA) into the oil phase, the solubility of PPDO decreased, the degree of wrinkles of the microspheres containing EtOH increased, and the internal structure was sponge loose, while EA promoted the precipitation of PPDO to a greater extent, resulting in a decrease in the balling rate of the prepared microspheres. This simple strategy considers the solubility and precipitation process of PPDO and provides an efficient way to prepare PPDO hollow microspheres from a single O/W emulsion solvent evaporation method.